Clip.cpp

Go to the documentation of this file.

 
// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Clip.h"
 
#include "AudioResampler.h"
#include "Exceptions.h"
#include "FFmpegReader.h"
#include "FrameMapper.h"
#include "QtImageReader.h"
#include "ChunkReader.h"
#include "DummyReader.h"
#include "Timeline.h"
#include "ZmqLogger.h"
 
#include <algorithm>
#include <cmath>
 
#ifdef USE_IMAGEMAGICK
    #include "MagickUtilities.h"
    #include "ImageReader.h"
    #include "TextReader.h"
#endif
 
#include <Qt>
 
using namespace openshot;
 
namespace {
    struct CompositeChoice { const char* name; CompositeType value; };
    const CompositeChoice composite_choices[] = {
        {"Normal",      COMPOSITE_SOURCE_OVER},
 
        // Darken group
        {"Darken",      COMPOSITE_DARKEN},
        {"Multiply",    COMPOSITE_MULTIPLY},
        {"Color Burn",  COMPOSITE_COLOR_BURN},
 
        // Lighten group
        {"Lighten",     COMPOSITE_LIGHTEN},
        {"Screen",      COMPOSITE_SCREEN},
        {"Color Dodge", COMPOSITE_COLOR_DODGE},
        {"Add",         COMPOSITE_PLUS},
 
        // Contrast group
        {"Overlay",     COMPOSITE_OVERLAY},
        {"Soft Light",  COMPOSITE_SOFT_LIGHT},
        {"Hard Light",  COMPOSITE_HARD_LIGHT},
 
        // Compare
        {"Difference",  COMPOSITE_DIFFERENCE},
        {"Exclusion",   COMPOSITE_EXCLUSION},
    };
    const int composite_choices_count = sizeof(composite_choices)/sizeof(CompositeChoice);
}
 
// Init default settings for a clip
void Clip::init_settings()
{
    // Init clip settings
    Position(0.0);
    Layer(0);
    Start(0.0);
    ClipBase::End(0.0);
    gravity = GRAVITY_CENTER;
    scale = SCALE_FIT;
    anchor = ANCHOR_CANVAS;
    display = FRAME_DISPLAY_NONE;
    mixing = VOLUME_MIX_NONE;
    composite = COMPOSITE_SOURCE_OVER;
    waveform = false;
    previous_properties = "";
    parentObjectId = "";
 
    // Init scale curves
    scale_x = Keyframe(1.0);
    scale_y = Keyframe(1.0);
 
    // Init location curves
    location_x = Keyframe(0.0);
    location_y = Keyframe(0.0);
 
    // Init alpha
    alpha = Keyframe(1.0);
 
    // Init time & volume
    time = Keyframe(1.0);
    volume = Keyframe(1.0);
 
    // Init audio waveform color
    wave_color = Color((unsigned char)0, (unsigned char)123, (unsigned char)255, (unsigned char)255);
 
    // Init shear and perspective curves
    shear_x = Keyframe(0.0);
    shear_y = Keyframe(0.0);
    origin_x = Keyframe(0.5);
    origin_y = Keyframe(0.5);
    perspective_c1_x = Keyframe(-1.0);
    perspective_c1_y = Keyframe(-1.0);
    perspective_c2_x = Keyframe(-1.0);
    perspective_c2_y = Keyframe(-1.0);
    perspective_c3_x = Keyframe(-1.0);
    perspective_c3_y = Keyframe(-1.0);
    perspective_c4_x = Keyframe(-1.0);
    perspective_c4_y = Keyframe(-1.0);
 
    // Init audio channel filter and mappings
    channel_filter = Keyframe(-1.0);
    channel_mapping = Keyframe(-1.0);
 
    // Init audio and video overrides
    has_audio = Keyframe(-1.0);
    has_video = Keyframe(-1.0);
 
    // Initialize the attached object and attached clip as null pointers
    parentTrackedObject = nullptr;
    parentClipObject = NULL;
 
    // Init reader info struct
    init_reader_settings();
}
 
// Init reader info details
void Clip::init_reader_settings() {
    if (reader) {
        // Init rotation (if any)
        init_reader_rotation();
 
        // Initialize info struct
        info = reader->info;
 
        // Init cache
        final_cache.SetMaxBytesFromInfo(8, info.width, info.height, info.sample_rate, info.channels);
    }
}
 
void Clip::init_reader_rotation() {
    // Only apply metadata rotation if clip rotation has not been explicitly set.
    if (rotation.GetCount() > 0 || !reader)
        return;
 
    const auto rotate_meta = reader->info.metadata.find("rotate");
    if (rotate_meta == reader->info.metadata.end()) {
        // Ensure rotation keyframes always start with a default 0° point.
        rotation = Keyframe(0.0f);
        return;
    }
 
    float rotate_angle = 0.0f;
    try {
        rotate_angle = strtof(rotate_meta->second.c_str(), nullptr);
    } catch (const std::exception& e) {
        return; // ignore invalid metadata
    }
 
    rotation = Keyframe(rotate_angle);
 
    // Do not overwrite user-authored scale curves.
    auto has_default_scale = [](const Keyframe& kf) {
        return kf.GetCount() == 1 && fabs(kf.GetPoint(0).co.Y - 1.0) < 0.00001;
    };
    if (!has_default_scale(scale_x) || !has_default_scale(scale_y))
        return;
 
    // No need to adjust scaling when the metadata rotation is effectively zero.
    if (fabs(rotate_angle) < 0.0001f)
        return;
 
    float w = static_cast<float>(reader->info.width);
    float h = static_cast<float>(reader->info.height);
    if (w <= 0.0f || h <= 0.0f)
        return;
 
    float rad = rotate_angle * static_cast<float>(M_PI) / 180.0f;
 
    float new_width  = fabs(w * cos(rad)) + fabs(h * sin(rad));
    float new_height = fabs(w * sin(rad)) + fabs(h * cos(rad));
    if (new_width <= 0.0f || new_height <= 0.0f)
        return;
 
    float uniform_scale = std::min(w / new_width, h / new_height);
 
    scale_x = Keyframe(uniform_scale);
    scale_y = Keyframe(uniform_scale);
}
 
// Default Constructor for a clip
Clip::Clip() : resampler(NULL), reader(NULL), allocated_reader(NULL), is_open(false)
{
    // Init all default settings
    init_settings();
}
 
// Constructor with reader
Clip::Clip(ReaderBase* new_reader) : resampler(NULL), reader(new_reader), allocated_reader(NULL), is_open(false)
{
    // Init all default settings
    init_settings();
 
    // Open and Close the reader (to set the duration of the clip)
    Open();
    Close();
 
    // Update duration and set parent
    if (reader) {
        ClipBase::End(reader->info.duration);
        reader->ParentClip(this);
        // Init reader info struct
        init_reader_settings();
    }
}
 
// Constructor with filepath
Clip::Clip(std::string path) : resampler(NULL), reader(NULL), allocated_reader(NULL), is_open(false)
{
    // Init all default settings
    init_settings();
 
    // Get file extension (and convert to lower case)
    std::string ext = get_file_extension(path);
    std::transform(ext.begin(), ext.end(), ext.begin(), ::tolower);
 
    // Determine if common video formats (or image sequences)
    if (ext=="avi" || ext=="mov" || ext=="mkv" ||  ext=="mpg" || ext=="mpeg" || ext=="mp3" || ext=="mp4" || ext=="mts" ||
        ext=="ogg" || ext=="wav" || ext=="wmv" || ext=="webm" || ext=="vob" || ext=="gif" || path.find("%") != std::string::npos)
    {
        try
        {
            // Open common video format
            reader = new openshot::FFmpegReader(path);
 
        } catch(...) { }
    }
    if (ext=="osp")
    {
        try
        {
            // Open common video format
            reader = new openshot::Timeline(path, true);
 
        } catch(...) { }
    }
 
 
    // If no video found, try each reader
    if (!reader)
    {
        try
        {
            // Try an image reader
            reader = new openshot::QtImageReader(path);
 
        } catch(...) {
            try
            {
                // Try a video reader
                reader = new openshot::FFmpegReader(path);
 
            } catch(...) { }
        }
    }
 
    // Update duration and set parent
    if (reader) {
        ClipBase::End(reader->info.duration);
        reader->ParentClip(this);
        allocated_reader = reader;
        // Init reader info struct
        init_reader_settings();
    }
}
 
// Destructor
Clip::~Clip()
{
    // Delete the reader if clip created it
    if (allocated_reader) {
        delete allocated_reader;
        allocated_reader = NULL;
        reader = NULL;
    }
 
    // Close the resampler
    if (resampler) {
        delete resampler;
        resampler = NULL;
    }
 
    // Close clip
    Close();
}
 
// Attach clip to bounding box
void Clip::AttachToObject(std::string object_id)
{
    // Search for the tracked object on the timeline
    Timeline* parentTimeline = static_cast<Timeline *>(ParentTimeline());
 
    if (parentTimeline) {
        // Create a smart pointer to the tracked object from the timeline
        std::shared_ptr<openshot::TrackedObjectBase> trackedObject = parentTimeline->GetTrackedObject(object_id);
        Clip* clipObject = parentTimeline->GetClip(object_id);
 
        // Check for valid tracked object
        if (trackedObject){
            SetAttachedObject(trackedObject);
            parentClipObject = NULL;
        }
        else if (clipObject) {
            SetAttachedClip(clipObject);
            parentTrackedObject = nullptr;
        }
    }
}
 
// Set the pointer to the trackedObject this clip is attached to
void Clip::SetAttachedObject(std::shared_ptr<openshot::TrackedObjectBase> trackedObject){
    parentTrackedObject = trackedObject;
}
 
// Set the pointer to the clip this clip is attached to
void Clip::SetAttachedClip(Clip* clipObject){
    parentClipObject = clipObject;
}

void Clip::Reader(ReaderBase* new_reader)
{
    // Delete previously allocated reader (if not related to new reader)
    // FrameMappers that point to the same allocated reader are ignored
    bool is_same_reader = false;
    if (new_reader && allocated_reader) {
        if (new_reader->Name() == "FrameMapper") {
            // Determine if FrameMapper is pointing at the same allocated ready
            FrameMapper* clip_mapped_reader = static_cast<FrameMapper*>(new_reader);
            if (allocated_reader == clip_mapped_reader->Reader()) {
                is_same_reader = true;
            }
        }
    }
    // Clear existing allocated reader (if different)
    if (allocated_reader && !is_same_reader) {
        reader->Close();
        allocated_reader->Close();
        delete allocated_reader;
        reader = NULL;
        allocated_reader = NULL;
    }
 
    // set reader pointer
    reader = new_reader;
 
    // set parent
    if (reader) {
        reader->ParentClip(this);
 
        // Init reader info struct
        init_reader_settings();
    }
}

ReaderBase* Clip::Reader()
{
    if (reader)
        return reader;
    else
        // Throw error if reader not initialized
        throw ReaderClosed("No Reader has been initialized for this Clip.  Call Reader(*reader) before calling this method.");
}
 
// Open the internal reader
void Clip::Open()
{
    if (reader)
    {
        // Open the reader
        reader->Open();
        is_open = true;
 
        // Copy Reader info to Clip
        info = reader->info;
 
        // Set some clip properties from the file reader
        if (end == 0.0)
            ClipBase::End(reader->info.duration);
    }
    else
        // Throw error if reader not initialized
        throw ReaderClosed("No Reader has been initialized for this Clip.  Call Reader(*reader) before calling this method.");
}
 
// Close the internal reader
void Clip::Close()
{
    if (is_open && reader) {
        ZmqLogger::Instance()->AppendDebugMethod("Clip::Close");
 
        // Close the reader
        reader->Close();
    }
 
    // Clear cache
    final_cache.Clear();
    is_open = false;
}
 
// Get end position of clip (trim end of video), which can be affected by the time curve.
float Clip::End() const
{
    // if a time curve is present, use its length
    if (time.GetCount() > 1)
    {
        // Determine the FPS fo this clip
        float fps = 24.0;
        if (reader)
            // file reader
            fps = reader->info.fps.ToFloat();
        else
            // Throw error if reader not initialized
            throw ReaderClosed("No Reader has been initialized for this Clip.  Call Reader(*reader) before calling this method.");
 
        return float(time.GetLength()) / fps;
    }
    else
        // just use the duration (as detected by the reader)
        return end;
}
 
// Override End() position
void Clip::End(float value) {
    ClipBase::End(value);
}
 
// Set associated Timeline pointer
void Clip::ParentTimeline(openshot::TimelineBase* new_timeline) {
    timeline = new_timeline;
 
    // Clear cache (it might have changed)
    final_cache.Clear();
}
 
// Create an openshot::Frame object for a specific frame number of this reader.
std::shared_ptr<Frame> Clip::GetFrame(int64_t clip_frame_number)
{
    // Call override of GetFrame
    return GetFrame(NULL, clip_frame_number, NULL);
}
 
// Create an openshot::Frame object for a specific frame number of this reader.
// NOTE: background_frame is ignored in this method (this method is only used by Effect classes)
std::shared_ptr<Frame> Clip::GetFrame(std::shared_ptr<openshot::Frame> background_frame, int64_t clip_frame_number)
{
    // Call override of GetFrame
    return GetFrame(background_frame, clip_frame_number, NULL);
}
 
// Use an existing openshot::Frame object and draw this Clip's frame onto it
std::shared_ptr<Frame> Clip::GetFrame(std::shared_ptr<openshot::Frame> background_frame, int64_t clip_frame_number, openshot::TimelineInfoStruct* options)
{
    // Check for open reader (or throw exception)
    if (!is_open)
        throw ReaderClosed("The Clip is closed.  Call Open() before calling this method.");
 
    if (reader)
    {
        // Get frame object
        std::shared_ptr<Frame> frame = NULL;
 
        // Check cache
        frame = final_cache.GetFrame(clip_frame_number);
        if (!frame) {
            // Generate clip frame
            frame = GetOrCreateFrame(clip_frame_number);
 
            // Get frame size and frame #
            int64_t timeline_frame_number = clip_frame_number;
            QSize timeline_size(frame->GetWidth(), frame->GetHeight());
            if (background_frame) {
                // If a background frame is provided, use it instead
                timeline_frame_number = background_frame->number;
                timeline_size.setWidth(background_frame->GetWidth());
                timeline_size.setHeight(background_frame->GetHeight());
            }
 
            // Get time mapped frame object (used to increase speed, change direction, etc...)
            apply_timemapping(frame);
 
            // Apply waveform image (if any)
            apply_waveform(frame, timeline_size);
 
            // Apply effects BEFORE applying keyframes (if any local or global effects are used)
            apply_effects(frame, timeline_frame_number, options, true);
 
            // Apply keyframe / transforms to current clip image
            apply_keyframes(frame, timeline_size);
 
            // Apply effects AFTER applying keyframes (if any local or global effects are used)
            apply_effects(frame, timeline_frame_number, options, false);
 
            // Add final frame to cache (before flattening into background_frame)
            final_cache.Add(frame);
        }
 
        if (!background_frame) {
            // Create missing background_frame w/ transparent color (if needed)
            background_frame = std::make_shared<Frame>(frame->number, frame->GetWidth(), frame->GetHeight(),
                                                       "#00000000",  frame->GetAudioSamplesCount(),
                                                       frame->GetAudioChannelsCount());
        }
 
        // Apply background canvas (i.e. flatten this image onto previous layer image)
        apply_background(frame, background_frame);
 
        // Return processed 'frame'
        return frame;
    }
    else
        // Throw error if reader not initialized
        throw ReaderClosed("No Reader has been initialized for this Clip.  Call Reader(*reader) before calling this method.");
}
 
// Look up an effect by ID
openshot::EffectBase* Clip::GetEffect(const std::string& id)
{
    // Find the matching effect (if any)
    for (const auto& effect : effects) {
        if (effect->Id() == id) {
            return effect;
        }
    }
    return nullptr;
}
 
// Return the associated ParentClip (if any)
openshot::Clip* Clip::GetParentClip() {
    if (!parentObjectId.empty() && (!parentClipObject && !parentTrackedObject)) {
        // Attach parent clip OR object to this clip
        AttachToObject(parentObjectId);
    }
    return parentClipObject;
}
 
// Return the associated Parent Tracked Object (if any)
std::shared_ptr<openshot::TrackedObjectBase> Clip::GetParentTrackedObject() {
    if (!parentObjectId.empty() && (!parentClipObject && !parentTrackedObject)) {
        // Attach parent clip OR object to this clip
        AttachToObject(parentObjectId);
    }
    return parentTrackedObject;
}
 
// Get file extension
std::string Clip::get_file_extension(std::string path)
{
    // Return last part of path safely (handle filenames without a dot)
    const auto dot_pos = path.find_last_of('.');
    if (dot_pos == std::string::npos || dot_pos + 1 >= path.size()) {
        return std::string();
    }
 
    return path.substr(dot_pos + 1);
}
 
// Adjust the audio and image of a time mapped frame
void Clip::apply_timemapping(std::shared_ptr<Frame> frame)
{
    // Check for valid reader
    if (!reader)
        // Throw error if reader not initialized
        throw ReaderClosed("No Reader has been initialized for this Clip.  Call Reader(*reader) before calling this method.");
 
    // Check for a valid time map curve
    if (time.GetLength() > 1)
    {
        const std::lock_guard<std::recursive_mutex> lock(getFrameMutex);
 
        int64_t clip_frame_number = frame->number;
        int64_t new_frame_number = adjust_frame_number_minimum(time.GetLong(clip_frame_number));
 
        // create buffer
        juce::AudioBuffer<float> *source_samples = nullptr;
 
        // Get delta (difference from this frame to the next time mapped frame: Y value)
        double delta = time.GetDelta(clip_frame_number + 1);
        const bool prev_is_increasing = time.IsIncreasing(clip_frame_number);
        const bool is_increasing = time.IsIncreasing(clip_frame_number + 1);
 
        // Determine length of source audio (in samples)
        // A delta of 1.0 == normal expected samples
        // A delta of 0.5 == 50% of normal expected samples
        // A delta of 2.0 == 200% of normal expected samples
        int target_sample_count = Frame::GetSamplesPerFrame(adjust_timeline_framenumber(clip_frame_number), Reader()->info.fps,
                                                              Reader()->info.sample_rate,
                                                              Reader()->info.channels);
        int source_sample_count = round(target_sample_count * fabs(delta));
 
        // Determine starting audio location
        AudioLocation location;
        if (previous_location.frame == 0 || abs(new_frame_number - previous_location.frame) > 2 || prev_is_increasing != is_increasing) {
            // No previous location OR gap detected
            location.frame = new_frame_number;
            location.sample_start = 0;
 
            // Create / Reset resampler
            // We don't want to interpolate between unrelated audio data
            if (resampler) {
                delete resampler;
                resampler = nullptr;
            }
            // Init resampler with # channels from Reader (should match the timeline)
            resampler = new AudioResampler(Reader()->info.channels);
 
            // Allocate buffer of silence to initialize some data inside the resampler
            // To prevent it from becoming input limited
            juce::AudioBuffer<float> init_samples(Reader()->info.channels, 64);
            init_samples.clear();
            resampler->SetBuffer(&init_samples, 1.0);
            resampler->GetResampledBuffer();
 
        } else {
            // Use previous location
            location = previous_location;
        }
 
        if (source_sample_count <= 0) {
            // Add silence and bail (we don't need any samples)
            frame->AddAudioSilence(target_sample_count);
            return;
        }
 
        // Allocate a new sample buffer for these delta frames
        source_samples = new juce::AudioBuffer<float>(Reader()->info.channels, source_sample_count);
        source_samples->clear();
 
        // Determine ending audio location
        int remaining_samples = source_sample_count;
        int source_pos = 0;
        while (remaining_samples > 0) {
            std::shared_ptr<Frame> source_frame = GetOrCreateFrame(location.frame, false);
            int frame_sample_count = source_frame->GetAudioSamplesCount() - location.sample_start;
 
            // Inform FrameMapper of the direction for THIS mapper frame
            if (auto *fm = dynamic_cast<FrameMapper*>(reader)) {
                fm->SetDirectionHint(is_increasing);
            }
            source_frame->SetAudioDirection(is_increasing);
 
            if (frame_sample_count == 0) {
                // No samples found in source frame (fill with silence)
                if (is_increasing) {
                    location.frame++;
                } else {
                    location.frame--;
                }
                location.sample_start = 0;
                break;
            }
            if (remaining_samples - frame_sample_count >= 0) {
                // Use all frame samples & increment location
                for (int channel = 0; channel < source_frame->GetAudioChannelsCount(); channel++) {
                    source_samples->addFrom(channel, source_pos, source_frame->GetAudioSamples(channel) + location.sample_start, frame_sample_count, 1.0f);
                }
                if (is_increasing) {
                    location.frame++;
                } else {
                    location.frame--;   
                }
                location.sample_start = 0;
                remaining_samples -= frame_sample_count;
                source_pos += frame_sample_count;
 
            } else {
                // Use just what is needed (and reverse samples)
                for (int channel = 0; channel < source_frame->GetAudioChannelsCount(); channel++) {
                    source_samples->addFrom(channel, source_pos, source_frame->GetAudioSamples(channel) + location.sample_start, remaining_samples, 1.0f);
                }
                location.sample_start += remaining_samples;
                remaining_samples = 0;
                source_pos += remaining_samples;
            }
 
        }
 
        // Resize audio for current frame object + fill with silence
        // We are fixing to clobber this with actual audio data (possibly resampled)
        frame->AddAudioSilence(target_sample_count);
 
        if (source_sample_count != target_sample_count) {
            // Resample audio (if needed)
            double resample_ratio = double(source_sample_count) / double(target_sample_count);
            resampler->SetBuffer(source_samples, resample_ratio);
 
            // Resample the data
            juce::AudioBuffer<float> *resampled_buffer = resampler->GetResampledBuffer();
 
            // Fill the frame with resampled data
            for (int channel = 0; channel < Reader()->info.channels; channel++) {
                // Add new (slower) samples, to the frame object
                frame->AddAudio(true, channel, 0, resampled_buffer->getReadPointer(channel, 0), std::min(resampled_buffer->getNumSamples(), target_sample_count), 1.0f);
            }
        } else {
            // Fill the frame
            for (int channel = 0; channel < Reader()->info.channels; channel++) {
                // Add new (slower) samples, to the frame object
                frame->AddAudio(true, channel, 0, source_samples->getReadPointer(channel, 0), target_sample_count, 1.0f);
            }
        }
 
        // Clean up
        delete source_samples;
 
        // Set previous location
        previous_location = location;
    }
}
 
// Adjust frame number minimum value
int64_t Clip::adjust_frame_number_minimum(int64_t frame_number)
{
    // Never return a frame number 0 or below
    if (frame_number < 1)
        return 1;
    else
        return frame_number;
 
}
 
// Get or generate a blank frame
std::shared_ptr<Frame> Clip::GetOrCreateFrame(int64_t number, bool enable_time)
{
    try {
        // Init to requested frame
        int64_t clip_frame_number = adjust_frame_number_minimum(number);
        bool is_increasing = true;
 
        // Adjust for time-mapping (if any)
        if (enable_time && time.GetLength() > 1) {
            is_increasing = time.IsIncreasing(clip_frame_number + 1);
            const int64_t time_frame_number = adjust_frame_number_minimum(time.GetLong(clip_frame_number));
            if (auto *fm = dynamic_cast<FrameMapper*>(reader)) {
                // Inform FrameMapper which direction this mapper frame is being requested
                fm->SetDirectionHint(is_increasing);
            }
            clip_frame_number = time_frame_number;
        }
 
        // Debug output
        ZmqLogger::Instance()->AppendDebugMethod(
                "Clip::GetOrCreateFrame (from reader)",
                "number", number, "clip_frame_number", clip_frame_number);
 
        // Attempt to get a frame (but this could fail if a reader has just been closed)
        auto reader_frame = reader->GetFrame(clip_frame_number);
        if (reader_frame) {
            // Override frame # (due to time-mapping might change it)
            reader_frame->number = number;
            reader_frame->SetAudioDirection(is_increasing);
 
            // Return real frame
            // Create a new copy of reader frame
            // This allows a clip to modify the pixels and audio of this frame without
            // changing the underlying reader's frame data
            auto reader_copy = std::make_shared<Frame>(*reader_frame.get());
            if (has_video.GetInt(number) == 0) {
                // No video, so add transparent pixels
                reader_copy->AddColor(QColor(Qt::transparent));
            }
            if (has_audio.GetInt(number) == 0 || number > reader->info.video_length) {
                // No audio, so include silence (also, mute audio if past end of reader)
                reader_copy->AddAudioSilence(reader_copy->GetAudioSamplesCount());
            }
            return reader_copy;
        }
 
    } catch (const ReaderClosed & e) {
        // ...
    } catch (const OutOfBoundsFrame & e) {
        // ...
    }
 
    // Estimate # of samples needed for this frame
    int estimated_samples_in_frame = Frame::GetSamplesPerFrame(number, reader->info.fps, reader->info.sample_rate, reader->info.channels);
 
    // Debug output
    ZmqLogger::Instance()->AppendDebugMethod(
        "Clip::GetOrCreateFrame (create blank)",
        "number", number,
        "estimated_samples_in_frame", estimated_samples_in_frame);
 
    // Create blank frame
    auto new_frame = std::make_shared<Frame>(
        number, reader->info.width, reader->info.height,
        "#000000", estimated_samples_in_frame, reader->info.channels);
    new_frame->SampleRate(reader->info.sample_rate);
    new_frame->ChannelsLayout(reader->info.channel_layout);
    new_frame->AddAudioSilence(estimated_samples_in_frame);
    return new_frame;
}
 
// Generate JSON string of this object
std::string Clip::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Get all properties for a specific frame
std::string Clip::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root;
    root["id"] = add_property_json("ID", 0.0, "string", Id(), NULL, -1, -1, true, requested_frame);
    root["position"] = add_property_json("Position", Position(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
    root["layer"] = add_property_json("Track", Layer(), "int", "", NULL, 0, 20, false, requested_frame);
    root["start"] = add_property_json("Start", Start(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
    root["end"] = add_property_json("End", End(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
    root["duration"] = add_property_json("Duration", Duration(), "float", "", NULL, 0, 30 * 60 * 60 * 48, true, requested_frame);
    root["gravity"] = add_property_json("Gravity", gravity, "int", "", NULL, 0, 8, false, requested_frame);
    root["scale"] = add_property_json("Scale", scale, "int", "", NULL, 0, 3, false, requested_frame);
    root["display"] = add_property_json("Frame Number", display, "int", "", NULL, 0, 3, false, requested_frame);
    root["mixing"] = add_property_json("Volume Mixing", mixing, "int", "", NULL, 0, 2, false, requested_frame);
    root["composite"] = add_property_json("Composite", composite, "int", "", NULL, 0, composite_choices_count - 1, false, requested_frame);
    root["waveform"] = add_property_json("Waveform", waveform, "int", "", NULL, 0, 1, false, requested_frame);
    root["parentObjectId"] = add_property_json("Parent", 0.0, "string", parentObjectId, NULL, -1, -1, false, requested_frame);
 
    // Add gravity choices (dropdown style)
    root["gravity"]["choices"].append(add_property_choice_json("Top Left", GRAVITY_TOP_LEFT, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Top Center", GRAVITY_TOP, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Top Right", GRAVITY_TOP_RIGHT, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Left", GRAVITY_LEFT, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Center", GRAVITY_CENTER, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Right", GRAVITY_RIGHT, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Bottom Left", GRAVITY_BOTTOM_LEFT, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Bottom Center", GRAVITY_BOTTOM, gravity));
    root["gravity"]["choices"].append(add_property_choice_json("Bottom Right", GRAVITY_BOTTOM_RIGHT, gravity));
 
    // Add scale choices (dropdown style)
    root["scale"]["choices"].append(add_property_choice_json("Crop", SCALE_CROP, scale));
    root["scale"]["choices"].append(add_property_choice_json("Best Fit", SCALE_FIT, scale));
    root["scale"]["choices"].append(add_property_choice_json("Stretch", SCALE_STRETCH, scale));
    root["scale"]["choices"].append(add_property_choice_json("None", SCALE_NONE, scale));
 
    // Add frame number display choices (dropdown style)
    root["display"]["choices"].append(add_property_choice_json("None", FRAME_DISPLAY_NONE, display));
    root["display"]["choices"].append(add_property_choice_json("Clip", FRAME_DISPLAY_CLIP, display));
    root["display"]["choices"].append(add_property_choice_json("Timeline", FRAME_DISPLAY_TIMELINE, display));
    root["display"]["choices"].append(add_property_choice_json("Both", FRAME_DISPLAY_BOTH, display));
 
    // Add volume mixing choices (dropdown style)
    root["mixing"]["choices"].append(add_property_choice_json("None", VOLUME_MIX_NONE, mixing));
    root["mixing"]["choices"].append(add_property_choice_json("Average", VOLUME_MIX_AVERAGE, mixing));
    root["mixing"]["choices"].append(add_property_choice_json("Reduce", VOLUME_MIX_REDUCE, mixing));
 
    // Add composite choices (dropdown style)
    for (int i = 0; i < composite_choices_count; ++i)
        root["composite"]["choices"].append(add_property_choice_json(composite_choices[i].name, composite_choices[i].value, composite));
 
    // Add waveform choices (dropdown style)
    root["waveform"]["choices"].append(add_property_choice_json("Yes", true, waveform));
    root["waveform"]["choices"].append(add_property_choice_json("No", false, waveform));
 
    // Add the parentClipObject's properties
    if (parentClipObject)
    {
        // Convert Clip's frame position to Timeline's frame position
        long clip_start_position = round(Position() * info.fps.ToDouble()) + 1;
        long clip_start_frame = (Start() * info.fps.ToDouble()) + 1;
        double timeline_frame_number = requested_frame + clip_start_position - clip_start_frame;
 
        // Correct the parent Clip Object properties by the clip's reference system
        float parentObject_location_x = parentClipObject->location_x.GetValue(timeline_frame_number);
        float parentObject_location_y = parentClipObject->location_y.GetValue(timeline_frame_number);
        float parentObject_scale_x = parentClipObject->scale_x.GetValue(timeline_frame_number);
        float parentObject_scale_y = parentClipObject->scale_y.GetValue(timeline_frame_number);
        float parentObject_shear_x = parentClipObject->shear_x.GetValue(timeline_frame_number);
        float parentObject_shear_y = parentClipObject->shear_y.GetValue(timeline_frame_number);
        float parentObject_rotation = parentClipObject->rotation.GetValue(timeline_frame_number);
 
        // Add the parent Clip Object properties to JSON
        root["location_x"] = add_property_json("Location X", parentObject_location_x, "float", "", &location_x, -1.0, 1.0, false, requested_frame);
        root["location_y"] = add_property_json("Location Y", parentObject_location_y, "float", "", &location_y, -1.0, 1.0, false, requested_frame);
        root["scale_x"] = add_property_json("Scale X", parentObject_scale_x, "float", "", &scale_x, 0.0, 1.0, false, requested_frame);
        root["scale_y"] = add_property_json("Scale Y", parentObject_scale_y, "float", "", &scale_y, 0.0, 1.0, false, requested_frame);
        root["rotation"] = add_property_json("Rotation", parentObject_rotation, "float", "", &rotation, -360, 360, false, requested_frame);
        root["shear_x"] = add_property_json("Shear X", parentObject_shear_x, "float", "", &shear_x, -1.0, 1.0, false, requested_frame);
        root["shear_y"] = add_property_json("Shear Y", parentObject_shear_y, "float", "", &shear_y, -1.0, 1.0, false, requested_frame);
    }
    else
    {
        // Add this own clip's properties to JSON
        root["location_x"] = add_property_json("Location X", location_x.GetValue(requested_frame), "float", "", &location_x, -1.0, 1.0, false, requested_frame);
        root["location_y"] = add_property_json("Location Y", location_y.GetValue(requested_frame), "float", "", &location_y, -1.0, 1.0, false, requested_frame);
        root["scale_x"] = add_property_json("Scale X", scale_x.GetValue(requested_frame), "float", "", &scale_x, 0.0, 1.0, false, requested_frame);
        root["scale_y"] = add_property_json("Scale Y", scale_y.GetValue(requested_frame), "float", "", &scale_y, 0.0, 1.0, false, requested_frame);
        root["rotation"] = add_property_json("Rotation", rotation.GetValue(requested_frame), "float", "", &rotation, -360, 360, false, requested_frame);
        root["shear_x"] = add_property_json("Shear X", shear_x.GetValue(requested_frame), "float", "", &shear_x, -1.0, 1.0, false, requested_frame);
        root["shear_y"] = add_property_json("Shear Y", shear_y.GetValue(requested_frame), "float", "", &shear_y, -1.0, 1.0, false, requested_frame);
    }
 
    // Keyframes
    root["alpha"] = add_property_json("Alpha", alpha.GetValue(requested_frame), "float", "", &alpha, 0.0, 1.0, false, requested_frame);
    root["origin_x"] = add_property_json("Origin X", origin_x.GetValue(requested_frame), "float", "", &origin_x, 0.0, 1.0, false, requested_frame);
    root["origin_y"] = add_property_json("Origin Y", origin_y.GetValue(requested_frame), "float", "", &origin_y, 0.0, 1.0, false, requested_frame);
    root["volume"] = add_property_json("Volume", volume.GetValue(requested_frame), "float", "", &volume, 0.0, 1.0, false, requested_frame);
    root["time"] = add_property_json("Time", time.GetValue(requested_frame), "float", "", &time, 0.0, 30 * 60 * 60 * 48, false, requested_frame);
    root["channel_filter"] = add_property_json("Channel Filter", channel_filter.GetValue(requested_frame), "int", "", &channel_filter, -1, 10, false, requested_frame);
    root["channel_mapping"] = add_property_json("Channel Mapping", channel_mapping.GetValue(requested_frame), "int", "", &channel_mapping, -1, 10, false, requested_frame);
    root["has_audio"] = add_property_json("Enable Audio", has_audio.GetValue(requested_frame), "int", "", &has_audio, -1, 1.0, false, requested_frame);
    root["has_video"] = add_property_json("Enable Video", has_video.GetValue(requested_frame), "int", "", &has_video, -1, 1.0, false, requested_frame);
 
    // Add enable audio/video choices (dropdown style)
    root["has_audio"]["choices"].append(add_property_choice_json("Auto", -1, has_audio.GetValue(requested_frame)));
    root["has_audio"]["choices"].append(add_property_choice_json("Off", 0, has_audio.GetValue(requested_frame)));
    root["has_audio"]["choices"].append(add_property_choice_json("On", 1, has_audio.GetValue(requested_frame)));
    root["has_video"]["choices"].append(add_property_choice_json("Auto", -1, has_video.GetValue(requested_frame)));
    root["has_video"]["choices"].append(add_property_choice_json("Off", 0, has_video.GetValue(requested_frame)));
    root["has_video"]["choices"].append(add_property_choice_json("On", 1, has_video.GetValue(requested_frame)));
 
    root["wave_color"] = add_property_json("Wave Color", 0.0, "color", "", &wave_color.red, 0, 255, false, requested_frame);
    root["wave_color"]["red"] = add_property_json("Red", wave_color.red.GetValue(requested_frame), "float", "", &wave_color.red, 0, 255, false, requested_frame);
    root["wave_color"]["blue"] = add_property_json("Blue", wave_color.blue.GetValue(requested_frame), "float", "", &wave_color.blue, 0, 255, false, requested_frame);
    root["wave_color"]["green"] = add_property_json("Green", wave_color.green.GetValue(requested_frame), "float", "", &wave_color.green, 0, 255, false, requested_frame);
    root["wave_color"]["alpha"] = add_property_json("Alpha", wave_color.alpha.GetValue(requested_frame), "float", "", &wave_color.alpha, 0, 255, false, requested_frame);
 
    // Return formatted string
    return root.toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Clip::JsonValue() const {
 
    // Create root json object
    Json::Value root = ClipBase::JsonValue(); // get parent properties
    root["parentObjectId"] = parentObjectId;
    root["gravity"] = gravity;
    root["scale"] = scale;
    root["anchor"] = anchor;
    root["display"] = display;
    root["mixing"] = mixing;
    root["composite"] = composite;
    root["waveform"] = waveform;
    root["scale_x"] = scale_x.JsonValue();
    root["scale_y"] = scale_y.JsonValue();
    root["location_x"] = location_x.JsonValue();
    root["location_y"] = location_y.JsonValue();
    root["alpha"] = alpha.JsonValue();
    root["rotation"] = rotation.JsonValue();
    root["time"] = time.JsonValue();
    root["volume"] = volume.JsonValue();
    root["wave_color"] = wave_color.JsonValue();
    root["shear_x"] = shear_x.JsonValue();
    root["shear_y"] = shear_y.JsonValue();
    root["origin_x"] = origin_x.JsonValue();
    root["origin_y"] = origin_y.JsonValue();
    root["channel_filter"] = channel_filter.JsonValue();
    root["channel_mapping"] = channel_mapping.JsonValue();
    root["has_audio"] = has_audio.JsonValue();
    root["has_video"] = has_video.JsonValue();
    root["perspective_c1_x"] = perspective_c1_x.JsonValue();
    root["perspective_c1_y"] = perspective_c1_y.JsonValue();
    root["perspective_c2_x"] = perspective_c2_x.JsonValue();
    root["perspective_c2_y"] = perspective_c2_y.JsonValue();
    root["perspective_c3_x"] = perspective_c3_x.JsonValue();
    root["perspective_c3_y"] = perspective_c3_y.JsonValue();
    root["perspective_c4_x"] = perspective_c4_x.JsonValue();
    root["perspective_c4_y"] = perspective_c4_y.JsonValue();
 
    // Add array of effects
    root["effects"] = Json::Value(Json::arrayValue);
 
    // loop through effects
    for (auto existing_effect : effects)
    {
        root["effects"].append(existing_effect->JsonValue());
    }
 
    if (reader)
        root["reader"] = reader->JsonValue();
    else
        root["reader"] = Json::Value(Json::objectValue);
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Clip::SetJson(const std::string value) {
 
    // Parse JSON string into JSON objects
    try
    {
        const Json::Value root = openshot::stringToJson(value);
        // Set all values that match
        SetJsonValue(root);
    }
    catch (const std::exception& e)
    {
        // Error parsing JSON (or missing keys)
        throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
    }
}
 
// Load Json::Value into this object
void Clip::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    ClipBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["parentObjectId"].isNull()){
        parentObjectId = root["parentObjectId"].asString();
        if (parentObjectId.size() > 0 && parentObjectId != ""){
            AttachToObject(parentObjectId);
        } else{
            parentTrackedObject = nullptr;
            parentClipObject = NULL;
        }
    }
    if (!root["gravity"].isNull())
        gravity = (GravityType) root["gravity"].asInt();
    if (!root["scale"].isNull())
        scale = (ScaleType) root["scale"].asInt();
    if (!root["anchor"].isNull())
        anchor = (AnchorType) root["anchor"].asInt();
    if (!root["display"].isNull())
        display = (FrameDisplayType) root["display"].asInt();
    if (!root["mixing"].isNull())
        mixing = (VolumeMixType) root["mixing"].asInt();
    if (!root["composite"].isNull())
        composite = (CompositeType) root["composite"].asInt();
    if (!root["waveform"].isNull())
        waveform = root["waveform"].asBool();
    if (!root["scale_x"].isNull())
        scale_x.SetJsonValue(root["scale_x"]);
    if (!root["scale_y"].isNull())
        scale_y.SetJsonValue(root["scale_y"]);
    if (!root["location_x"].isNull())
        location_x.SetJsonValue(root["location_x"]);
    if (!root["location_y"].isNull())
        location_y.SetJsonValue(root["location_y"]);
    if (!root["alpha"].isNull())
        alpha.SetJsonValue(root["alpha"]);
    if (!root["rotation"].isNull())
        rotation.SetJsonValue(root["rotation"]);
    if (!root["time"].isNull())
        time.SetJsonValue(root["time"]);
    if (!root["volume"].isNull())
        volume.SetJsonValue(root["volume"]);
    if (!root["wave_color"].isNull())
        wave_color.SetJsonValue(root["wave_color"]);
    if (!root["shear_x"].isNull())
        shear_x.SetJsonValue(root["shear_x"]);
    if (!root["shear_y"].isNull())
        shear_y.SetJsonValue(root["shear_y"]);
    if (!root["origin_x"].isNull())
        origin_x.SetJsonValue(root["origin_x"]);
    if (!root["origin_y"].isNull())
        origin_y.SetJsonValue(root["origin_y"]);
    if (!root["channel_filter"].isNull())
        channel_filter.SetJsonValue(root["channel_filter"]);
    if (!root["channel_mapping"].isNull())
        channel_mapping.SetJsonValue(root["channel_mapping"]);
    if (!root["has_audio"].isNull())
        has_audio.SetJsonValue(root["has_audio"]);
    if (!root["has_video"].isNull())
        has_video.SetJsonValue(root["has_video"]);
    if (!root["perspective_c1_x"].isNull())
        perspective_c1_x.SetJsonValue(root["perspective_c1_x"]);
    if (!root["perspective_c1_y"].isNull())
        perspective_c1_y.SetJsonValue(root["perspective_c1_y"]);
    if (!root["perspective_c2_x"].isNull())
        perspective_c2_x.SetJsonValue(root["perspective_c2_x"]);
    if (!root["perspective_c2_y"].isNull())
        perspective_c2_y.SetJsonValue(root["perspective_c2_y"]);
    if (!root["perspective_c3_x"].isNull())
        perspective_c3_x.SetJsonValue(root["perspective_c3_x"]);
    if (!root["perspective_c3_y"].isNull())
        perspective_c3_y.SetJsonValue(root["perspective_c3_y"]);
    if (!root["perspective_c4_x"].isNull())
        perspective_c4_x.SetJsonValue(root["perspective_c4_x"]);
    if (!root["perspective_c4_y"].isNull())
        perspective_c4_y.SetJsonValue(root["perspective_c4_y"]);
    if (!root["effects"].isNull()) {
 
        // Clear existing effects
        effects.clear();
 
        // loop through effects
        for (const auto existing_effect : root["effects"]) {
            // Skip NULL nodes
            if (existing_effect.isNull()) {
                continue;
            }
 
            // Create Effect
            EffectBase *e = NULL;
            if (!existing_effect["type"].isNull()) {
 
                // Create instance of effect
                if ( (e = EffectInfo().CreateEffect(existing_effect["type"].asString()))) {
 
                    // Load Json into Effect
                    e->SetJsonValue(existing_effect);
 
                    // Add Effect to Timeline
                    AddEffect(e);
                }
            }
        }
    }
    if (!root["reader"].isNull()) // does Json contain a reader?
    {
        if (!root["reader"]["type"].isNull()) // does the reader Json contain a 'type'?
        {
            // Close previous reader (if any)
            bool already_open = false;
            if (reader)
            {
                // Track if reader was open
                already_open = reader->IsOpen();
 
                // Close and delete existing allocated reader (if any)
                Reader(NULL);
            }
 
            // Create new reader (and load properties)
            std::string type = root["reader"]["type"].asString();
 
            if (type == "FFmpegReader") {
 
                // Create new reader
                reader = new openshot::FFmpegReader(root["reader"]["path"].asString(), false);
                reader->SetJsonValue(root["reader"]);
 
            } else if (type == "QtImageReader") {
 
                // Create new reader
                reader = new openshot::QtImageReader(root["reader"]["path"].asString(), false);
                reader->SetJsonValue(root["reader"]);
 
#ifdef USE_IMAGEMAGICK
            } else if (type == "ImageReader") {
 
                // Create new reader
                reader = new ImageReader(root["reader"]["path"].asString(), false);
                reader->SetJsonValue(root["reader"]);
 
            } else if (type == "TextReader") {
 
                // Create new reader
                reader = new TextReader();
                reader->SetJsonValue(root["reader"]);
#endif
 
            } else if (type == "ChunkReader") {
 
                // Create new reader
                reader = new openshot::ChunkReader(root["reader"]["path"].asString(), (ChunkVersion) root["reader"]["chunk_version"].asInt());
                reader->SetJsonValue(root["reader"]);
 
            } else if (type == "DummyReader") {
 
                // Create new reader
                reader = new openshot::DummyReader();
                reader->SetJsonValue(root["reader"]);
 
            } else if (type == "Timeline") {
 
                // Create new reader (always load from file again)
                // This prevents FrameMappers from being loaded on accident
                reader = new openshot::Timeline(root["reader"]["path"].asString(), true);
            }
 
            // mark as managed reader and set parent
            if (reader) {
                reader->ParentClip(this);
                allocated_reader = reader;
            }
 
            // Re-Open reader (if needed)
            if (already_open) {
                reader->Open();
            }
        }
    }
 
    // Clear cache (it might have changed)
    final_cache.Clear();
}
 
// Sort effects by order
void Clip::sort_effects()
{
    // sort clips
    effects.sort(CompareClipEffects());
}
 
// Add an effect to the clip
void Clip::AddEffect(EffectBase* effect)
{
    // Set parent clip pointer
    effect->ParentClip(this);
 
    // Add effect to list
    effects.push_back(effect);
 
    // Sort effects
    sort_effects();
 
    // Get the parent timeline of this clip
    Timeline* parentTimeline = static_cast<Timeline *>(ParentTimeline());
 
    if (parentTimeline)
        effect->ParentTimeline(parentTimeline);
 
    #ifdef USE_OPENCV
    // Add Tracked Object to Timeline
    if (effect->info.has_tracked_object){
 
        // Check if this clip has a parent timeline
        if (parentTimeline){
 
            effect->ParentTimeline(parentTimeline);
 
            // Iterate through effect's vector of Tracked Objects
            for (auto const& trackedObject : effect->trackedObjects){
 
                // Cast the Tracked Object as TrackedObjectBBox
                std::shared_ptr<TrackedObjectBBox> trackedObjectBBox = std::static_pointer_cast<TrackedObjectBBox>(trackedObject.second);
 
                // Set the Tracked Object's parent clip to this
                trackedObjectBBox->ParentClip(this);
 
                // Add the Tracked Object to the timeline
                parentTimeline->AddTrackedObject(trackedObjectBBox);
            }
        }
    }
    #endif
 
    // Clear cache (it might have changed)
    final_cache.Clear();
}
 
// Remove an effect from the clip
void Clip::RemoveEffect(EffectBase* effect)
{
    effects.remove(effect);
 
    // Clear cache (it might have changed)
    final_cache.Clear();
}
 
// Apply background image to the current clip image (i.e. flatten this image onto previous layer)
void Clip::apply_background(std::shared_ptr<openshot::Frame> frame, std::shared_ptr<openshot::Frame> background_frame) {
    // Add background canvas
    std::shared_ptr<QImage> background_canvas = background_frame->GetImage();
    QPainter painter(background_canvas.get());
 
    // Composite a new layer onto the image
    painter.setCompositionMode(static_cast<QPainter::CompositionMode>(composite));
    painter.drawImage(0, 0, *frame->GetImage());
    painter.end();
 
    // Add new QImage to frame
    frame->AddImage(background_canvas);
}
 
// Apply effects to the source frame (if any)
void Clip::apply_effects(std::shared_ptr<Frame> frame, int64_t timeline_frame_number, TimelineInfoStruct* options, bool before_keyframes)
{
    for (auto effect : effects)
    {
        // Apply the effect to this frame
        if (effect->info.apply_before_clip && before_keyframes) {
            effect->GetFrame(frame, frame->number);
        } else if (!effect->info.apply_before_clip && !before_keyframes) {
            effect->GetFrame(frame, frame->number);
        }
    }
 
    if (timeline != NULL && options != NULL) {
        // Apply global timeline effects (i.e. transitions & masks... if any)
        Timeline* timeline_instance = static_cast<Timeline*>(timeline);
        options->is_before_clip_keyframes = before_keyframes;
        timeline_instance->apply_effects(frame, timeline_frame_number, Layer(), options);
    }
}
 
// Compare 2 floating point numbers for equality
bool Clip::isNear(double a, double b)
{
    return fabs(a - b) < 0.000001;
}
 
// Apply keyframes to the source frame (if any)
void Clip::apply_keyframes(std::shared_ptr<Frame> frame, QSize timeline_size) {
    // Skip out if video was disabled or only an audio frame (no visualisation in use)
    if (!frame->has_image_data) {
        // Skip the rest of the image processing for performance reasons
        return;
    }
 
    // Get image from clip, and create transparent background image
    std::shared_ptr<QImage> source_image = frame->GetImage();
    std::shared_ptr<QImage> background_canvas = std::make_shared<QImage>(timeline_size.width(),
                                                                         timeline_size.height(),
                                                                         QImage::Format_RGBA8888_Premultiplied);
    background_canvas->fill(QColor(Qt::transparent));
 
    // Get transform from clip's keyframes
    QTransform transform = get_transform(frame, background_canvas->width(), background_canvas->height());
 
    // Load timeline's new frame image into a QPainter
    QPainter painter(background_canvas.get());
    painter.setRenderHint(QPainter::TextAntialiasing, true);
    if (!transform.isIdentity()) {
        painter.setRenderHint(QPainter::SmoothPixmapTransform, true);
    }
    // Apply transform (translate, rotate, scale)
    painter.setTransform(transform);
 
    // Composite a new layer onto the image
    painter.setCompositionMode(static_cast<QPainter::CompositionMode>(composite));
 
    // Apply opacity via painter instead of per-pixel alpha manipulation
    const float alpha_value = alpha.GetValue(frame->number);
    if (alpha_value != 1.0f) {
        painter.setOpacity(alpha_value);
        painter.drawImage(0, 0, *source_image);
        // Reset so any subsequent drawing (e.g., overlays) isn’t faded
        painter.setOpacity(1.0);
    } else {
        painter.drawImage(0, 0, *source_image);
    }
 
    if (timeline) {
        Timeline *t = static_cast<Timeline *>(timeline);
 
        // Draw frame #'s on top of image (if needed)
        if (display != FRAME_DISPLAY_NONE) {
            std::stringstream frame_number_str;
            switch (display) {
                case (FRAME_DISPLAY_NONE):
                    // This is only here to prevent unused-enum warnings
                    break;
 
                case (FRAME_DISPLAY_CLIP):
                    frame_number_str << frame->number;
                    break;
 
                case (FRAME_DISPLAY_TIMELINE):
                    frame_number_str << round((Position() - Start()) * t->info.fps.ToFloat()) + frame->number;
                    break;
 
                case (FRAME_DISPLAY_BOTH):
                    frame_number_str << round((Position() - Start()) * t->info.fps.ToFloat()) + frame->number << " (" << frame->number << ")";
                    break;
            }
 
            // Draw frame number on top of image
            painter.setPen(QColor("#ffffff"));
            painter.drawText(20, 20, QString(frame_number_str.str().c_str()));
        }
    }
    painter.end();
 
    // Add new QImage to frame
    frame->AddImage(background_canvas);
}
 
// Apply apply_waveform image to the source frame (if any)
void Clip::apply_waveform(std::shared_ptr<Frame> frame, QSize timeline_size) {
 
    if (!Waveform()) {
        // Exit if no waveform is needed
        return;
    }
 
    // Get image from clip
    std::shared_ptr<QImage> source_image = frame->GetImage();
 
    // Debug output
    ZmqLogger::Instance()->AppendDebugMethod("Clip::apply_waveform (Generate Waveform Image)",
            "frame->number", frame->number,
            "Waveform()", Waveform(),
            "width", timeline_size.width(),
            "height", timeline_size.height());
 
    // Get the color of the waveform
    int red = wave_color.red.GetInt(frame->number);
    int green = wave_color.green.GetInt(frame->number);
    int blue = wave_color.blue.GetInt(frame->number);
    int alpha = wave_color.alpha.GetInt(frame->number);
 
    // Generate Waveform Dynamically (the size of the timeline)
    source_image = frame->GetWaveform(timeline_size.width(), timeline_size.height(), red, green, blue, alpha);
    frame->AddImage(source_image);
}
 
// Scale a source size to a target size (given a specific scale-type)
QSize Clip::scale_size(QSize source_size, ScaleType source_scale, int target_width, int target_height) {
    switch (source_scale)
    {
        case (SCALE_FIT): {
            source_size.scale(target_width, target_height, Qt::KeepAspectRatio);
            break;
        }
        case (SCALE_STRETCH): {
            source_size.scale(target_width, target_height, Qt::IgnoreAspectRatio);
            break;
        }
        case (SCALE_CROP): {
            source_size.scale(target_width, target_height, Qt::KeepAspectRatioByExpanding);;
            break;
        }
    }
 
    return source_size;
}
 
// Get QTransform from keyframes
QTransform Clip::get_transform(std::shared_ptr<Frame> frame, int width, int height)
{
    // Get image from clip
    std::shared_ptr<QImage> source_image = frame->GetImage();
 
    /* RESIZE SOURCE IMAGE - based on scale type */
    QSize source_size = scale_size(source_image->size(), scale, width, height);
 
    // Initialize parent object's properties (Clip or Tracked Object)
    float parentObject_location_x = 0.0;
    float parentObject_location_y = 0.0;
    float parentObject_scale_x = 1.0;
    float parentObject_scale_y = 1.0;
    float parentObject_shear_x = 0.0;
    float parentObject_shear_y = 0.0;
    float parentObject_rotation = 0.0;
 
    // Get the parentClipObject properties
    if (GetParentClip()){
        // Get the start trim position of the parent clip
        long parent_start_offset = parentClipObject->Start() * info.fps.ToDouble();
        long parent_frame_number = frame->number + parent_start_offset;
 
        // Get parent object's properties (Clip)
        parentObject_location_x = parentClipObject->location_x.GetValue(parent_frame_number);
        parentObject_location_y = parentClipObject->location_y.GetValue(parent_frame_number);
        parentObject_scale_x = parentClipObject->scale_x.GetValue(parent_frame_number);
        parentObject_scale_y = parentClipObject->scale_y.GetValue(parent_frame_number);
        parentObject_shear_x = parentClipObject->shear_x.GetValue(parent_frame_number);
        parentObject_shear_y = parentClipObject->shear_y.GetValue(parent_frame_number);
        parentObject_rotation = parentClipObject->rotation.GetValue(parent_frame_number);
    }
 
    // Get the parentTrackedObject properties
    if (GetParentTrackedObject()){
        // Get the attached object's parent clip's properties
        Clip* parentClip = (Clip*) parentTrackedObject->ParentClip();
        if (parentClip)
        {
            // Get the start trim position of the parent clip
            long parent_start_offset = parentClip->Start() * info.fps.ToDouble();
            long parent_frame_number = frame->number + parent_start_offset;
 
            // Access the parentTrackedObject's properties
            std::map<std::string, float> trackedObjectProperties = parentTrackedObject->GetBoxValues(parent_frame_number);
 
            // Get actual scaled parent size
            QSize parent_size = scale_size(QSize(parentClip->info.width, parentClip->info.height),
                                           parentClip->scale, width, height);
 
            // Get actual scaled tracked object size
            int trackedWidth = trackedObjectProperties["w"] * trackedObjectProperties["sx"] * parent_size.width() *
                    parentClip->scale_x.GetValue(parent_frame_number);
            int trackedHeight = trackedObjectProperties["h"] * trackedObjectProperties["sy"] * parent_size.height() *
                    parentClip->scale_y.GetValue(parent_frame_number);
 
            // Scale the clip source_size based on the actual tracked object size
            source_size = scale_size(source_size, scale, trackedWidth, trackedHeight);
 
            // Update parentObject's properties based on the tracked object's properties and parent clip's scale
            parentObject_location_x = parentClip->location_x.GetValue(parent_frame_number) + ((trackedObjectProperties["cx"] - 0.5) * parentClip->scale_x.GetValue(parent_frame_number));
            parentObject_location_y = parentClip->location_y.GetValue(parent_frame_number) + ((trackedObjectProperties["cy"] - 0.5) * parentClip->scale_y.GetValue(parent_frame_number));
            parentObject_rotation = trackedObjectProperties["r"] + parentClip->rotation.GetValue(parent_frame_number);
        }
    }
 
    /* GRAVITY LOCATION - Initialize X & Y to the correct values (before applying location curves) */
    float x = 0.0; // left
    float y = 0.0; // top
 
    // Adjust size for scale x and scale y
    float sx = scale_x.GetValue(frame->number); // percentage X scale
    float sy = scale_y.GetValue(frame->number); // percentage Y scale
 
    // Change clip's scale to parentObject's scale
    if(parentObject_scale_x != 0.0 && parentObject_scale_y != 0.0){
        sx*= parentObject_scale_x;
        sy*= parentObject_scale_y;
    }
 
    float scaled_source_width = source_size.width() * sx;
    float scaled_source_height = source_size.height() * sy;
 
    switch (gravity)
    {
        case (GRAVITY_TOP_LEFT):
            // This is only here to prevent unused-enum warnings
            break;
        case (GRAVITY_TOP):
            x = (width - scaled_source_width) / 2.0; // center
            break;
        case (GRAVITY_TOP_RIGHT):
            x = width - scaled_source_width; // right
            break;
        case (GRAVITY_LEFT):
            y = (height - scaled_source_height) / 2.0; // center
            break;
        case (GRAVITY_CENTER):
            x = (width - scaled_source_width) / 2.0; // center
            y = (height - scaled_source_height) / 2.0; // center
            break;
        case (GRAVITY_RIGHT):
            x = width - scaled_source_width; // right
            y = (height - scaled_source_height) / 2.0; // center
            break;
        case (GRAVITY_BOTTOM_LEFT):
            y = (height - scaled_source_height); // bottom
            break;
        case (GRAVITY_BOTTOM):
            x = (width - scaled_source_width) / 2.0; // center
            y = (height - scaled_source_height); // bottom
            break;
        case (GRAVITY_BOTTOM_RIGHT):
            x = width - scaled_source_width; // right
            y = (height - scaled_source_height); // bottom
            break;
    }
 
    // Debug output
    ZmqLogger::Instance()->AppendDebugMethod(
        "Clip::get_transform (Gravity)",
        "frame->number", frame->number,
        "source_clip->gravity", gravity,
        "scaled_source_width", scaled_source_width,
        "scaled_source_height", scaled_source_height);
 
    QTransform transform;
 
    /* LOCATION, ROTATION, AND SCALE */
    float r = rotation.GetValue(frame->number) + parentObject_rotation; // rotate in degrees
    x += width * (location_x.GetValue(frame->number) + parentObject_location_x); // move in percentage of final width
    y += height * (location_y.GetValue(frame->number) + parentObject_location_y); // move in percentage of final height
    float shear_x_value = shear_x.GetValue(frame->number) + parentObject_shear_x;
    float shear_y_value = shear_y.GetValue(frame->number) + parentObject_shear_y;
    float origin_x_value = origin_x.GetValue(frame->number);
    float origin_y_value = origin_y.GetValue(frame->number);
 
    // Transform source image (if needed)
    ZmqLogger::Instance()->AppendDebugMethod(
        "Clip::get_transform (Build QTransform - if needed)",
        "frame->number", frame->number,
        "x", x, "y", y,
        "r", r,
        "sx", sx, "sy", sy);
 
    if (!isNear(x, 0) || !isNear(y, 0)) {
        // TRANSLATE/MOVE CLIP
        transform.translate(x, y);
    }
    if (!isNear(r, 0) || !isNear(shear_x_value, 0) || !isNear(shear_y_value, 0)) {
        // ROTATE CLIP (around origin_x, origin_y)
        float origin_x_offset = (scaled_source_width * origin_x_value);
        float origin_y_offset = (scaled_source_height * origin_y_value);
        transform.translate(origin_x_offset, origin_y_offset);
        transform.rotate(r);
        transform.shear(shear_x_value, shear_y_value);
        transform.translate(-origin_x_offset,-origin_y_offset);
    }
    // SCALE CLIP (if needed)
    float source_width_scale = (float(source_size.width()) / float(source_image->width())) * sx;
    float source_height_scale = (float(source_size.height()) / float(source_image->height())) * sy;
    if (!isNear(source_width_scale, 1.0) || !isNear(source_height_scale, 1.0)) {
        transform.scale(source_width_scale, source_height_scale);
    }
 
    return transform;
}
 
// Adjust frame number for Clip position and start (which can result in a different number)
int64_t Clip::adjust_timeline_framenumber(int64_t clip_frame_number) {
 
    // Get clip position from parent clip (if any)
    float position = 0.0;
    float start = 0.0;
    Clip *parent = static_cast<Clip *>(ParentClip());
    if (parent) {
        position = parent->Position();
        start = parent->Start();
    }
 
    // Adjust start frame and position based on parent clip.
    // This ensures the same frame # is used by mapped readers and clips,
    // when calculating samples per frame.
    // Thus, this prevents gaps and mismatches in # of samples.
    int64_t clip_start_frame = (start * info.fps.ToDouble()) + 1;
    int64_t clip_start_position = round(position * info.fps.ToDouble()) + 1;
    int64_t frame_number = clip_frame_number + clip_start_position - clip_start_frame;
 
    return frame_number;
}