FFMEPG -- A ffmpeg and SDL Tutorial : tutorial03

參考 http://dranger.com/ffmpeg/tutorial03.html 進行實作練習，以下附上一個可以在 ffmpeg 1.1.1 (build Jan 27 2013) 正確編譯的例子。



// tutorial03.c // A pedagogical video player that will stream through every video frame as fast as it can // and play audio (out of sync). // // Code based on FFplay, Copyright (c) 2003 Fabrice Bellard, // and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de) // Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1 // Use // // gcc -o tutorial03 tutorial03.c -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs` // to build (assuming libavformat and libavcodec are correctly installed, // and assuming you have sdl-config. Please refer to SDL docs for your installation.) // // Run using // tutorial03 myvideofile.mpg // // to play the stream on your screen. // 20130204 albert.liao modified start //#include //#include //#include //#include #include #include #include #include #include //#undef main /* Prevents SDL from overriding main() */ // 20130204 albert.liao modified end #ifdef __MINGW32__ #undef main /* Prevents SDL from overriding main() */ #endif #include #define SDL_AUDIO_BUFFER_SIZE 1024 typedef struct PacketQueue { AVPacketList *first_pkt, *last_pkt; int nb_packets; int size; SDL_mutex *mutex; SDL_cond *cond; } PacketQueue; PacketQueue audioq; int quit = 0; void packet_queue_init(PacketQueue *q) { memset(q, 0, sizeof(PacketQueue)); q->mutex = SDL_CreateMutex(); q->cond = SDL_CreateCond(); } int packet_queue_put(PacketQueue *q, AVPacket *pkt) { AVPacketList *pkt1; if(av_dup_packet(pkt) < 0) { return -1; } pkt1 = av_malloc(sizeof(AVPacketList)); if (!pkt1) return -1; pkt1->pkt = *pkt; pkt1->next = NULL; SDL_LockMutex(q->mutex); if (!q->last_pkt) q->first_pkt = pkt1; else q->last_pkt->next = pkt1; q->last_pkt = pkt1; q->nb_packets++; q->size += pkt1->pkt.size; SDL_CondSignal(q->cond); SDL_UnlockMutex(q->mutex); return 0; } static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { AVPacketList *pkt1; int ret; SDL_LockMutex(q->mutex); for(;;) { if(quit) { ret = -1; break; } pkt1 = q->first_pkt; if (pkt1) { q->first_pkt = pkt1->next; if (!q->first_pkt) q->last_pkt = NULL; q->nb_packets--; q->size -= pkt1->pkt.size; *pkt = pkt1->pkt; av_free(pkt1); ret = 1; break; } else if (!block) { ret = 0; break; } else { SDL_CondWait(q->cond, q->mutex); } } SDL_UnlockMutex(q->mutex); return ret; } // 20130204 albert.liao modified start #if 0 int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) { static AVPacket pkt; static uint8_t *audio_pkt_data = NULL; static int audio_pkt_size = 0; int len1, data_size; for(;;) { while(audio_pkt_size > 0) { data_size = buf_size; len1 = avcodec_decode_audio2(aCodecCtx, (int16_t *)audio_buf, &data_size, audio_pkt_data, audio_pkt_size); if(len1 < 0) { /* if error, skip frame */ audio_pkt_size = 0; break; } audio_pkt_data += len1; audio_pkt_size -= len1; if(data_size <= 0) { /* No data yet, get more frames */ continue; } /* We have data, return it and come back for more later */ return data_size; } if(pkt.data) av_free_packet(&pkt); if(quit) { return -1; } if(packet_queue_get(&audioq, &pkt, 1) < 0) { return -1; } audio_pkt_data = pkt.data; audio_pkt_size = pkt.size; } } #endif int audio_decode_frame(AVCodecContext *aCodecCtx, AVPacket *pkt,AVPacket *pkt_temp, AVFrame *frame, uint8_t *audio_buf) { int len1, data_size; int got_frame; int new_packet = 0; for(;;) { while(pkt_temp->size > 0 || (!pkt_temp->data && new_packet)) { if(!frame) { if (!(frame = avcodec_alloc_frame())) return AVERROR(ENOMEM); } else { avcodec_get_frame_defaults(frame); } new_packet = 0; len1 = avcodec_decode_audio4(aCodecCtx, frame, &got_frame, pkt_temp); if(len1 < 0) { /* if error, skip frame */ pkt_temp->size = 0; break; } pkt_temp->data += len1; pkt_temp->size -= len1; if (!got_frame) { /* stop sending empty packets if the decoder is finished */ continue; } data_size = av_samples_get_buffer_size(NULL, aCodecCtx->channels, frame->nb_samples, aCodecCtx->sample_fmt, 1); //audio_buf = frame->data[0]; memcpy(audio_buf,frame->data[0],frame->linesize[0]); return data_size; } if(pkt->data) av_free_packet(pkt); memset(pkt_temp, 0, sizeof(*pkt_temp)); if(quit) { return -1; } if((new_packet = packet_queue_get(&audioq, pkt, 1)) < 0) { return -1; } *pkt_temp = *pkt; } } // 20130204 albert.liao modified end void audio_callback(void *userdata, Uint8 *stream, int len) { AVCodecContext *aCodecCtx = (AVCodecContext *)userdata; int len1, audio_size; static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; static unsigned int audio_buf_size = 0; static unsigned int audio_buf_index = 0; // 20130204 albert.liao modified start AVPacket *pkt = av_mallocz(sizeof(AVPacket)); AVPacket *pkt_temp = av_mallocz(sizeof(AVPacket)); AVFrame *frame = NULL; // 20130204 albert.liao modified end while(len > 0) { if(audio_buf_index >= audio_buf_size) { /* We have already sent all our data; get more */ // 20130204 albert.liao modified start //audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf)); audio_size = audio_decode_frame(aCodecCtx, pkt, pkt_temp, frame, audio_buf); // 20130204 albert.liao modified end if(audio_size < 0) { /* If error, output silence */ audio_buf_size = 1024; // arbitrary? memset(audio_buf, 0, audio_buf_size); } else { audio_buf_size = audio_size; } audio_buf_index = 0; } len1 = audio_buf_size - audio_buf_index; if(len1 > len) len1 = len; memcpy(stream, (uint8_t *)audio_buf + audio_buf_index, len1); len -= len1; stream += len1; audio_buf_index += len1; } } int main(int argc, char *argv[]) { AVFormatContext *pFormatCtx; int i, videoStream, audioStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; int frameFinished; float aspect_ratio; // 201302023 albert.liao modified start struct SwsContext *img_convert_ctx; // 201302023 albert.liao modified end AVCodecContext *aCodecCtx; AVCodec *aCodec; SDL_Overlay *bmp; SDL_Surface *screen; SDL_Rect rect; SDL_Event event; SDL_AudioSpec wanted_spec, spec; if(argc < 2) { fprintf(stderr, "Usage: test \n"); exit(1); } // Register all formats and codecs av_register_all(); if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); exit(1); } // Open video file // 20130204 albert.liao modified start // Open video file //if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0) pFormatCtx = avformat_alloc_context(); if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0) return -1; // Couldn't open file // 20130204 albert.liao modified end // 201302023 albert.liao modified start //if(av_find_stream_info(pFormatCtx)<0 data-blogger-escaped--1="" data-blogger-escaped-0="" data-blogger-escaped-201302023="" data-blogger-escaped-about="" data-blogger-escaped-albert.liao="" data-blogger-escaped-argv="" data-blogger-escaped-audiostream="-1;" data-blogger-escaped-av_dump_format="" data-blogger-escaped-avformat_find_stream_info="" data-blogger-escaped-couldn="" data-blogger-escaped-dump="" data-blogger-escaped-dump_format="" data-blogger-escaped-end="" data-blogger-escaped-error="" data-blogger-escaped-file="" data-blogger-escaped-find="" data-blogger-escaped-first="" data-blogger-escaped-for="" data-blogger-escaped-i="" data-blogger-escaped-if="" data-blogger-escaped-information="" data-blogger-escaped-modified="" data-blogger-escaped-onto="" data-blogger-escaped-pformatctx-="" data-blogger-escaped-pformatctx="" data-blogger-escaped-return="" data-blogger-escaped-standard="" data-blogger-escaped-stream="" data-blogger-escaped-t="" data-blogger-escaped-the="" data-blogger-escaped-video="" data-blogger-escaped-videostream="-1;">nb_streams; i++) { // 201302023 albert.liao modified start //if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO && videoStream < 0) { if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO && videoStream < 0) { videoStream=i; } //if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_AUDIO && audioStream < 0) { if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO && audioStream < 0) { audioStream=i; } // 201302023 albert.liao modified end } if(videoStream==-1) return -1; // Didn't find a video stream if(audioStream==-1) return -1; aCodecCtx=pFormatCtx->streams[audioStream]->codec; // Set audio settings from codec info wanted_spec.freq = aCodecCtx->sample_rate; wanted_spec.format = AUDIO_S16SYS; wanted_spec.channels = aCodecCtx->channels; wanted_spec.silence = 0; wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE; wanted_spec.callback = audio_callback; wanted_spec.userdata = aCodecCtx; if(SDL_OpenAudio(&wanted_spec, &spec) < 0) { fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError()); return -1; } aCodec = avcodec_find_decoder(aCodecCtx->codec_id); if(!aCodec) { fprintf(stderr, "Unsupported codec!\n"); return -1; } // 20130204 albert.liao modified start // Open codec //if(avcodec_open(aCodecCtx, aCodec)<0 data-blogger-escaped--1="" data-blogger-escaped-20130204="" data-blogger-escaped-acodec="" data-blogger-escaped-acodecctx="" data-blogger-escaped-albert.liao="" data-blogger-escaped-audio_st="pFormatCtx-" data-blogger-escaped-avcodec_open2="" data-blogger-escaped-codec="" data-blogger-escaped-could="" data-blogger-escaped-end="" data-blogger-escaped-if="" data-blogger-escaped-modified="" data-blogger-escaped-not="" data-blogger-escaped-null="" data-blogger-escaped-open="" data-blogger-escaped-return="">streams[index] packet_queue_init(&audioq); SDL_PauseAudio(0); // Get a pointer to the codec context for the video stream pCodecCtx=pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec=avcodec_find_decoder(pCodecCtx->codec_id); if(pCodec==NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // 20130204 albert.liao modified start // Open codec //if(avcodec_open(pCodecCtx, pCodec)<0 data-blogger-escaped--1="" data-blogger-escaped-20130204="" data-blogger-escaped-__darwin__="" data-blogger-escaped-a="" data-blogger-escaped-albert.liao="" data-blogger-escaped-allocate="" data-blogger-escaped-avcodec_open2="" data-blogger-escaped-codec="" data-blogger-escaped-could="" data-blogger-escaped-end="" data-blogger-escaped-frame="" data-blogger-escaped-if="" data-blogger-escaped-ifndef="" data-blogger-escaped-make="" data-blogger-escaped-modified="" data-blogger-escaped-not="" data-blogger-escaped-null="" data-blogger-escaped-open="" data-blogger-escaped-our="" data-blogger-escaped-pcodec="" data-blogger-escaped-pcodecctx="" data-blogger-escaped-pframe="avcodec_alloc_frame();" data-blogger-escaped-put="" data-blogger-escaped-return="" data-blogger-escaped-screen="SDL_SetVideoMode(pCodecCtx-" data-blogger-escaped-to="" data-blogger-escaped-video="">width, pCodecCtx->height, 0, 0); #else screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0); #endif if(!screen) { fprintf(stderr, "SDL: could not set video mode - exiting\n"); exit(1); } // Allocate a place to put our YUV image on that screen bmp = SDL_CreateYUVOverlay(pCodecCtx->width, pCodecCtx->height, SDL_YV12_OVERLAY, screen); // Read frames and save first five frames to disk i=0; while(av_read_frame(pFormatCtx, &packet)>=0) { // Is this a packet from the video stream? if(packet.stream_index==videoStream) { // 20130204 albert.liao modified start // Decode video frame // avcodec_decode_video(pCodecCtx, pFrame, &frameFinished, packet.data, packet.size); avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet); // 20130204 albert.liao modified end // Did we get a video frame? if(frameFinished) { SDL_LockYUVOverlay(bmp); AVPicture pict; pict.data[0] = bmp->pixels[0]; pict.data[1] = bmp->pixels[2]; pict.data[2] = bmp->pixels[1]; pict.linesize[0] = bmp->pitches[0]; pict.linesize[1] = bmp->pitches[2]; pict.linesize[2] = bmp->pitches[1]; // 20130204 albert.liao modified start // Convert the image into YUV format that SDL uses //img_convert(&pict, PIX_FMT_YUV420P, // (AVPicture *)pFrame, pCodecCtx->pix_fmt, // pCodecCtx->width, pCodecCtx->height); img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height,\ pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height,\ PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL); // other codes // Convert the image from its native format to RGB sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize,\ 0, pCodecCtx->height, pict.data, pict.linesize); // 20130204 albert.liao modified end SDL_UnlockYUVOverlay(bmp); rect.x = 0; rect.y = 0; rect.w = pCodecCtx->width; rect.h = pCodecCtx->height; SDL_DisplayYUVOverlay(bmp, &rect); av_free_packet(&packet); } } else if(packet.stream_index==audioStream) { packet_queue_put(&audioq, &packet); } else { av_free_packet(&packet); } // Free the packet that was allocated by av_read_frame SDL_PollEvent(&event); switch(event.type) { case SDL_QUIT: quit = 1; SDL_Quit(); exit(0); break; default: break; } } // Free the YUV frame av_free(pFrame); // Close the codec avcodec_close(pCodecCtx); // 20130204 albert.liao modified start // Close the video file // av_close_input_file(pFormatCtx); avformat_close_input(&pFormatCtx); // 20130204 albert.liao modified end return 0; }