/** * @file container-mpg.ino * @author Phil Schatzmann * @brief Self-contained round-trip test for ContainerMPG: MuxerMPG writes * synthetic MPEG-1 video/audio elementary-stream frames into an in-memory * MPEG-1 Program Stream, DemuxerMPG parses that stream back apart while * being fed the bytes in small, arbitrarily-sized chunks (exercising the * partial-write/resync logic), and the reassembled elementary streams, * frame counts and parsed VideoInfo/AudioInfo are compared against what was * originally written. No external files/hardware required. * * To build & run: * - mkdir build && cd build && cmake .. && make * - ./container-mpg * * @copyright Copyright (c) 2025 */ #include #include #include "AudioTools.h" #include "AudioTools/AudioCodecs/ContainerMPG.h" #include "AudioTools/CoreAudio/BaseStream.h" using namespace audio_tools; /// Collects everything written to it (for byte-exact comparison) and counts /// flush() calls (one expected per demuxed video access unit). class VerifyPrint : public Print { public: Vector data; int flush_count = 0; size_t write(uint8_t c) override { return write(&c, 1); } size_t write(const uint8_t *buf, size_t len) override { for (size_t i = 0; i < len; i++) { uint8_t b = buf[i]; data.push_back(b); } return len; } void flush() override { flush_count++; } }; static void appendPattern(Vector &v, size_t n, uint8_t seed) { for (size_t i = 0; i < n; i++) v.push_back((uint8_t)(seed + i)); } static bool sameBytes(Vector &a, Vector &b) { if (a.size() != b.size()) { printf(" size mismatch: %d vs %d\n", (int)a.size(), (int)b.size()); return false; } for (int i = 0; i < a.size(); i++) { if (a[i] != b[i]) { printf(" byte %d mismatch: 0x%02X vs 0x%02X\n", i, a[i], b[i]); return false; } } return true; } void setup() { Serial.begin(115200); AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Warning); const uint16_t kWidth = 64; const uint16_t kHeight = 48; const float kFps = 25.0f; // must be one of the ISO 11172-2 rate table values const uint32_t kSampleRate = 44100; const uint8_t kChannels = 2; const int kVideoFrames = 5; const int kAudioFrames = 5; // ---- 1) mux synthetic frames into an in-memory Program Stream, ------ // keeping a copy of everything written for later comparison. // (frames are built and muxed one at a time in the same loop rather // than stored in a Vector> - this codebase's Vector // does not support non-POD/nested element types.) Vector expected_video; Vector expected_audio; DynamicMemoryStream mux_buffer; mux_buffer.begin(); MuxerMPG muxer(mux_buffer); MuxerVideoConfig cfg; cfg.width = kWidth; cfg.height = kHeight; cfg.fps = kFps; cfg.format = VideoFormat::MPEG1; muxer.setVideoInfo(cfg); muxer.setAudioInfo(AudioInfoFormat(kSampleRate, kChannels, 16, AudioFormat::MP3)); assert(muxer.begin()); for (int i = 0; i < kVideoFrames; i++) { Vector frame; if (i == 0) { // sequence_header: width=64, height=48, aspect=1, rate_index=3 (25fps) uint8_t hdr[8] = {0x00, 0x00, 0x01, 0xB3, 0x04, 0x00, 0x30, 0x13}; for (int j = 0; j < 8; j++) frame.push_back(hdr[j]); } else { // fake picture_start_code so it at least looks like an access unit uint8_t hdr[4] = {0x00, 0x00, 0x01, 0x00}; for (int j = 0; j < 4; j++) frame.push_back(hdr[j]); } // frame 2 is oversized to force MuxerMPG's multi-pack chunking size_t payload = (i == 2) ? 10000 : 40; appendPattern(frame, payload, (uint8_t)(0x10 * i)); size_t written = muxer.addVideoFrame(frame.data(), frame.size()); assert(written == (size_t)frame.size()); for (int j = 0; j < frame.size(); j++) expected_video.push_back(frame[j]); if (i < kAudioFrames) { Vector aframe; // MPEG-1 Layer III, 44100 Hz, stereo sync/header (a real MP3 header) uint8_t ahdr[4] = {0xFF, 0xFB, 0x50, 0x04}; for (int j = 0; j < 4; j++) aframe.push_back(ahdr[j]); appendPattern(aframe, 60, (uint8_t)(0x80 + i)); size_t awritten = muxer.addAudioFrame(aframe.data(), aframe.size()); assert(awritten == (size_t)aframe.size()); for (int j = 0; j < aframe.size(); j++) expected_audio.push_back(aframe[j]); } } muxer.end(); printf("Muxed program stream: %d bytes\n", (int)mux_buffer.size()); assert(mux_buffer.size() > 0); // ---- 3) demux, feeding bytes back in small, awkward-sized chunks --- mux_buffer.rewind(); DemuxerMPG demuxer; VerifyPrint video_out; VerifyPrint audio_out; demuxer.setOutputVideo(video_out); demuxer.setOutputAudio(audio_out); assert(demuxer.begin()); const size_t kChunk = 23; // deliberately not aligned to any header size uint8_t buf[kChunk]; int total_fed = 0; while (mux_buffer.available() > 0) { size_t n = mux_buffer.readBytes(buf, kChunk); if (n == 0) break; size_t written = demuxer.write(buf, n); assert(written == n); total_fed += (int)n; } demuxer.end(); printf("Fed %d bytes into DemuxerMPG\n", total_fed); // ---- 4) verify ------------------------------------------------------ bool ok = true; printf("Checking video ES round-trip...\n"); if (!sameBytes(expected_video, video_out.data)) ok = false; printf("Checking audio ES round-trip...\n"); if (!sameBytes(expected_audio, audio_out.data)) ok = false; printf("video flush() count: %d (expected %d)\n", video_out.flush_count, kVideoFrames); if (video_out.flush_count != kVideoFrames) ok = false; VideoInfo vi = demuxer.getVideoInfo(); printf("parsed VideoInfo: %d x %d @ %.3f fps\n", (int)vi.width, (int)vi.height, vi.fps); if (vi.width != kWidth || vi.height != kHeight || vi.fps != kFps) ok = false; AudioInfoFormat ai = demuxer.getAudioInfo(); printf("parsed AudioInfo: %d Hz, %d ch\n", (int)ai.sample_rate, (int)ai.channels); if (ai.sample_rate != kSampleRate || ai.channels != kChannels) ok = false; if (ok) { printf("PASS: ContainerMPG round-trip OK\n"); } else { printf("FAIL: ContainerMPG round-trip mismatch\n"); } assert(ok); exit(ok ? 0 : 1); } void loop() {}