Mkvcinemas.h Info

engine.setFrameCallback(handle, [](const mkv::Frame& f) // Simple console visualizer (ASCII art) std::cout << "Frame @ " << f.pts.count() << "ns\n"; );

class AssProvider : public mkv::SubtitleProvider public: explicit AssProvider(const std::string& assFile); std::optional<Subtitle> getSubtitle(std::chrono::nanoseconds pts) override; private: // Parsed ASS events stored internally ; The engine called getSubtitle for each frame, and the UI rendered the stylized text atop the video. The seamless integration was possible because used pure virtual interfaces for extensions, keeping the core lightweight. 4.2 The Audio‑Sync Disaster Leo pushed the engine into a VR experiment, feeding frames at 90 fps while the audio pipeline ran at 48 kHz. Initially, lips lagged because the engine’s internal clock drifted. Mara added a SyncGuard class: mkvcinemas.h

// Register a callback for frame‑ready events using FrameCallback = std::function<void(const Frame&)>; void setFrameCallback(MediaHandle, FrameCallback); private: // Implementation hidden – pImpl idiom to keep ABI stable struct Impl; std::unique_ptr<Impl> pImpl_; ; engine

// Custom allocator (optional) std::function<void*(std::size_t)> alloc = nullptr; std::function<void(void*)> dealloc = nullptr; ; Why it mattered : EngineConfig gave the control over performance vs. quality trade‑offs, making mkvcinemas.h suitable for everything from low‑power ARM tablets to high‑end 8‑K home theaters. 2.3 struct Frame struct Frame const uint8_t* data; // Pointer to raw pixel data (RGB, YUV, etc.) std::size_t stride; // Bytes per row uint32_t width, height; PixelFormat fmt; // Enum: RGB24, YUV420, etc. std::chrono::nanoseconds pts; // Presentation timestamp bool isKeyFrame; ; Why it mattered : By handing out a const view of the frame, mkvcinemas.h let applications render directly into a GPU texture or write to a custom compositor without copying. The pts field ensured perfect synchronization with audio. Chapter 3 – The First Test: “Midnight at the Oasis” Mara invited her friends— Leo (a graphics guru), Tara (audio engineer), and Sam (the UI designer)—to a demo night. They compiled a minimal program: Initially, lips lagged because the engine’s internal clock

int main() mkv::EngineConfig cfg; cfg.videoBackend = mkv::EngineConfig::Backend::Vulkan; cfg.decoder = mkv::EngineConfig::Decoder::Hybrid; mkv::CinemaEngine engine(cfg);

// Query state PlaybackState state(MediaHandle h) const noexcept;