ChunkWriter.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "ChunkWriter.h"
#include "Exceptions.h"
#include "Frame.h"
 
using namespace openshot;
 
ChunkWriter::ChunkWriter(std::string path, ReaderBase *reader) :
        local_reader(reader), path(path), chunk_size(24*3), chunk_count(1), frame_count(1), is_writing(false),
        default_extension(".webm"), default_vcodec("libvpx"), default_acodec("libvorbis"), last_frame_needed(false), is_open(false)
{
    // Change codecs to default
    info.vcodec = default_vcodec;
    info.acodec = default_acodec;
 
    // Copy info struct from the source reader
    CopyReaderInfo(local_reader);
 
    // Create folder (if it does not exist)
    create_folder(path);
 
    // Write JSON meta data file
    write_json_meta_data();
 
    // Open reader
    local_reader->Open();
}
 
// get a formatted path of a specific chunk
std::string ChunkWriter::get_chunk_path(int64_t chunk_number, std::string folder, std::string extension)
{
    // Create path of new chunk video
    std::stringstream chunk_count_string;
    chunk_count_string << chunk_number;
    QString padded_count = "%1"; //chunk_count_string.str().c_str();
    padded_count = padded_count.arg(chunk_count_string.str().c_str(), 6, '0');
    if (folder.length() != 0 && extension.length() != 0)
        // Return path with FOLDER and EXTENSION name
        return QDir::cleanPath(QString(path.c_str()) + QDir::separator() + folder.c_str() + QDir::separator() + padded_count + extension.c_str()).toStdString();
 
    else if (folder.length() == 0 && extension.length() != 0)
        // Return path with NO FOLDER and EXTENSION name
        return QDir::cleanPath(QString(path.c_str()) + QDir::separator() + padded_count + extension.c_str()).toStdString();
 
    else if (folder.length() != 0 && extension.length() == 0)
        // Return path with FOLDER and NO EXTENSION
        return QDir::cleanPath(QString(path.c_str()) + QDir::separator() + folder.c_str()).toStdString();
    else
        return "";
}
 
// Add a frame to the queue waiting to be encoded.
void ChunkWriter::WriteFrame(std::shared_ptr<openshot::Frame> frame)
{
    // Check for open reader (or throw exception)
    if (!is_open)
        throw WriterClosed("The ChunkWriter is closed.  Call Open() before calling this method.", path);
 
    // Check if currently writing chunks?
    if (!is_writing)
    {
        // Save thumbnail of chunk start frame
        frame->Save(get_chunk_path(chunk_count, "", ".jpeg"), 1.0);
 
        // Create FFmpegWriter (FINAL quality)
        create_folder(get_chunk_path(chunk_count, "final", ""));
        writer_final = new FFmpegWriter(get_chunk_path(chunk_count, "final", default_extension));
        writer_final->SetAudioOptions(true, default_acodec, info.sample_rate, info.channels, info.channel_layout, 128000);
        writer_final->SetVideoOptions(true, default_vcodec, info.fps, info.width, info.height, info.pixel_ratio, false, false, info.video_bit_rate);
 
        // Create FFmpegWriter (PREVIEW quality)
        create_folder(get_chunk_path(chunk_count, "preview", ""));
        writer_preview = new FFmpegWriter(get_chunk_path(chunk_count, "preview", default_extension));
        writer_preview->SetAudioOptions(true, default_acodec, info.sample_rate, info.channels, info.channel_layout, 128000);
        writer_preview->SetVideoOptions(true, default_vcodec, info.fps, info.width * 0.5, info.height * 0.5, info.pixel_ratio, false, false, info.video_bit_rate * 0.5);
 
        // Create FFmpegWriter (LOW quality)
        create_folder(get_chunk_path(chunk_count, "thumb", ""));
        writer_thumb = new FFmpegWriter(get_chunk_path(chunk_count, "thumb", default_extension));
        writer_thumb->SetAudioOptions(true, default_acodec, info.sample_rate, info.channels, info.channel_layout, 128000);
        writer_thumb->SetVideoOptions(true, default_vcodec, info.fps, info.width * 0.25, info.height * 0.25, info.pixel_ratio, false, false, info.video_bit_rate * 0.25);
 
        // Prepare Streams
        writer_final->PrepareStreams();
        writer_preview->PrepareStreams();
        writer_thumb->PrepareStreams();
 
        // Write header
        writer_final->WriteHeader();
        writer_preview->WriteHeader();
        writer_thumb->WriteHeader();
 
        // Keep track that a chunk is being written
        is_writing = true;
        last_frame_needed = true;
    }
 
    // If this is not the 1st chunk, always start frame 1 with the last frame from the previous
    // chunk. This helps to prevent audio resampling issues (because it "stokes" the sample array)
    if (last_frame_needed)
    {
        if (last_frame)
        {
            // Write the previous chunks LAST FRAME to the current chunk
            writer_final->WriteFrame(last_frame);
            writer_preview->WriteFrame(last_frame);
            writer_thumb->WriteFrame(last_frame);
        } else {
            // Write the 1st frame (of the 1st chunk)... since no previous chunk is available
            auto blank_frame = std::make_shared<Frame>(
                1, info.width, info.height, "#000000",
                info.sample_rate, info.channels);
            blank_frame->AddColor(info.width, info.height, "#000000");
            writer_final->WriteFrame(blank_frame);
            writer_preview->WriteFrame(blank_frame);
            writer_thumb->WriteFrame(blank_frame);
        }
 
        // disable last frame
        last_frame_needed = false;
    }
 

    // WRITE THE CURRENT FRAME TO THE CURRENT CHUNK
    writer_final->WriteFrame(frame);
    writer_preview->WriteFrame(frame);
    writer_thumb->WriteFrame(frame);
 
 
    // Write the frames once it reaches the correct chunk size
    if (frame_count % chunk_size == 0 && frame_count >= chunk_size)
    {
        // Pad an additional 12 frames
        for (int z = 0; z<12; z++)
        {
            // Repeat frame
            writer_final->WriteFrame(frame);
            writer_preview->WriteFrame(frame);
            writer_thumb->WriteFrame(frame);
        }
 
        // Write Footer
        writer_final->WriteTrailer();
        writer_preview->WriteTrailer();
        writer_thumb->WriteTrailer();
 
        // Close writer & reader
        writer_final->Close();
        writer_preview->Close();
        writer_thumb->Close();
 
        // Increment chunk count
        chunk_count++;
 
        // Stop writing chunk
        is_writing = false;
    }
 
    // Increment frame counter
    frame_count++;
 
    // Keep track of the last frame added
    last_frame = frame;
}
 
 
// Write a block of frames from a reader
void ChunkWriter::WriteFrame(ReaderBase* reader, int64_t start, int64_t length)
{
    // Loop through each frame (and encoded it)
    for (int64_t number = start; number <= length; number++)
    {
        // Get the frame
        std::shared_ptr<Frame> f = reader->GetFrame(number);
 
        // Encode frame
        WriteFrame(f);
    }
}
 
// Write a block of frames from the local cached reader
void ChunkWriter::WriteFrame(int64_t start, int64_t length)
{
    // Loop through each frame (and encoded it)
    for (int64_t number = start; number <= length; number++)
    {
        // Get the frame
        std::shared_ptr<Frame> f = local_reader->GetFrame(number);
 
        // Encode frame
        WriteFrame(f);
    }
}
 
// Close the writer
void ChunkWriter::Close()
{
    // Write the frames once it reaches the correct chunk size
    if (is_writing)
    {
        // Pad an additional 12 frames
        for (int z = 0; z<12; z++)
        {
            // Repeat frame
            writer_final->WriteFrame(last_frame);
            writer_preview->WriteFrame(last_frame);
            writer_thumb->WriteFrame(last_frame);
        }
 
        // Write Footer
        writer_final->WriteTrailer();
        writer_preview->WriteTrailer();
        writer_thumb->WriteTrailer();
 
        // Close writer & reader
        writer_final->Close();
        writer_preview->Close();
        writer_thumb->Close();
 
        // Increment chunk count
        chunk_count++;
 
        // Stop writing chunk
        is_writing = false;
    }
 
    // close writer
    is_open = false;
 
    // Reset frame counters
    chunk_count = 0;
    frame_count = 0;
 
    // Open reader
    local_reader->Close();
}
 
// write JSON meta data
void ChunkWriter::write_json_meta_data()
{
    // Load path of chunk folder
    std::string json_path = QDir::cleanPath(QString(path.c_str()) + QDir::separator() + "info.json").toStdString();
 
    // Write JSON file
    std::ofstream myfile;
    myfile.open (json_path.c_str());
    myfile << local_reader->Json() << std::endl;
    myfile.close();
}
 
// check for chunk folder
void ChunkWriter::create_folder(std::string path)
{
    QDir dir(path.c_str());
    if (!dir.exists()) {
        dir.mkpath(".");
    }
}
 
// check for valid chunk json
bool ChunkWriter::is_chunk_valid()
{
    return true;
}
 
// Open the writer
void ChunkWriter::Open()
{
    is_open = true;
}