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/**
* @file
* @brief Example application showing how to attach VideoCacheThread to an FFmpegReader
* @author Jonathan Thomas <jonathan@openshot.org>
*
* @ref License
*/
// Copyright (c) 2008-2025 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
#include <chrono>
#include <iostream>
#include <memory>
#include "Frame.h"
#include "FFmpegReader.h"
#include "FFmpegWriter.h"
#include "Timeline.h"
#include "Qt/VideoCacheThread.h" // <— your new header
using namespace openshot;
int main(int argc, char* argv[]) {
// 1) Open the FFmpegReader as usual
const char* input_path = "sintel_trailer-720p.mp4";
FFmpegReader reader(input_path);
reader.Open();
const int64_t total_frames = reader.info.video_length;
std::cout << "Total frames: " << total_frames << "\n";
Timeline timeline(reader.info.width, reader.info.height, reader.info.fps, reader.info.sample_rate, reader.info.channels, reader.info.channel_layout);
Clip c1(&reader);
timeline.AddClip(&c1);
timeline.Open();
timeline.DisplayInfo();
// 2) Construct a VideoCacheThread around 'reader' and start its background loop
// (VideoCacheThread inherits juce::Thread)
std::shared_ptr<VideoCacheThread> cache = std::make_shared<VideoCacheThread>();
cache->Reader(&timeline); // attaches the FFmpegReader and internally calls Play()
cache->StartThread(); // juce::Thread method, begins run()
// 3) Set up the writer exactly as before
FFmpegWriter writer("performance-cachetest.mp4");
writer.SetAudioOptions("aac", 48000, 192000);
writer.SetVideoOptions("libx264", 1280, 720, Fraction(30, 1), 5000000);
writer.Open();
// 4) Forward pass: for each frame 1…N, tell the cache thread to seek to that frame,
// then immediately call cache->GetFrame(frame), which will block only if that frame
// hasn’t been decoded into the cache yet.
auto t0 = std::chrono::high_resolution_clock::now();
cache->setSpeed(1);
for (int64_t f = 1; f <= total_frames; ++f) {
float pct = (float(f) / total_frames) * 100.0f;
std::cout << "Forward: requesting frame " << f << " (" << pct << "%)\n";
cache->Seek(f); // signal “I need frame f now (and please prefetch f+1, f+2, …)”
std::shared_ptr<Frame> framePtr = timeline.GetFrame(f);
writer.WriteFrame(framePtr);
}
auto t1 = std::chrono::high_resolution_clock::now();
auto forward_ms = std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0).count();
// 5) Backward pass: same idea in reverse
auto t2 = std::chrono::high_resolution_clock::now();
cache->setSpeed(-1);
for (int64_t f = total_frames; f >= 1; --f) {
float pct = (float(total_frames - f + 1) / total_frames) * 100.0f;
std::cout << "Backward: requesting frame " << f << " (" << pct << "%)\n";
cache->Seek(f);
std::shared_ptr<Frame> framePtr = timeline.GetFrame(f);
writer.WriteFrame(framePtr);
}
auto t3 = std::chrono::high_resolution_clock::now();
auto backward_ms = std::chrono::duration_cast<std::chrono::milliseconds>(t3 - t2).count();
std::cout << "\nForward pass elapsed: " << forward_ms << " ms\n";
std::cout << "Backward pass elapsed: " << backward_ms << " ms\n";
// 6) Shut down the cache thread, close everything
cache->StopThread(10000); // politely tells run() to exit, waits up to 10s
reader.Close();
writer.Close();
timeline.Close();
return 0;
}
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