ffmpeg 0.6.3 能用的tutorial03

编译totorial03.c的命令为：
gcc -o tutorial03 tutorial03.c -lavformat -lavcodec -lz -lm -lswscale `sdl-config --cflags --libs`

#include <libavcodec/avcodec.h>
    #include <libavformat/avformat.h>
    #include <libswscale/swscale.h>

    #include <SDL/SDL.h>
    #include <SDL/SDL_thread.h>

    #include <stdio.h>

    #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;
    }

    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) {
                    audio_pkt_size = 0;
                    break;
                }
                audio_pkt_data += len1;
                audio_pkt_size -= len1;
                if (data_size <= 0) {
                    continue;
                }
                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;
        }
    }

    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;

        while (len > 0) {
            if (audio_buf_index >= audio_buf_size) {
                audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf));
                if (audio_size < 0) {
                    audio_buf_size = 1024;
                    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;
        struct SwsContext *img_convert_ctx;

        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);
        }
        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);
        }

        if (av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL) != 0) {
            return -1;
        }

        if (av_find_stream_info(pFormatCtx) < 0) {
            return -1;
        }

        dump_format(pFormatCtx, 0, argv[1], 0);

        videoStream = -1;
        audioStream = -1;
        for (i=0; i<pFormatCtx->nb_streams; i++) {
            if (pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO && videoStream < 0) {
                videoStream = i;
            }
            if (pFormatCtx->streams[i]->codec->codec_type == CODEC_TYPE_AUDIO && audioStream < 0) {
                audioStream = i;
            }
        }

        if (videoStream == -1) {
            return -1;
        }
        if (audioStream == -1) {
            return -1;
        }

        aCodecCtx = pFormatCtx->streams[audioStream]->codec;

        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;
        }
        avcodec_open(aCodecCtx, aCodec);

        packet_queue_init(&audioq);
        SDL_PauseAudio(0);

        pCodecCtx=pFormatCtx->streams[videoStream]->codec;
        img_convert_ctx = sws_getContext(pCodecCtx->width,
                pCodecCtx->height,
                pCodecCtx->pix_fmt,
                pCodecCtx->width,
                pCodecCtx->height,
                PIX_FMT_YUV420P,
                SWS_BICUBIC,
                NULL, NULL, NULL);


        pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
        if (pCodec == NULL) {
            fprintf(stderr, "Unsupported codec!\n");
            return -1;
        }
        if (avcodec_open(pCodecCtx, pCodec) < 0) {
            return -1;
        }

        pFrame = avcodec_alloc_frame();

        screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0);

        if (!screen) {
            fprintf(stderr, "SDL : could not set video mode - exiting\n");
            exit(1);
        }

        bmp = SDL_CreateYUVOverlay(pCodecCtx->width,
                           pCodecCtx->height,
                       SDL_YV12_OVERLAY,
                       screen);
        i = 0;
        while(av_read_frame(pFormatCtx, &packet) >= 0) {
            if (packet.stream_index == videoStream) {
                avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
                        packet.data, packet.size);

                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];

                    sws_scale(img_convert_ctx,
                            pFrame->data,
                            pFrame->linesize, 0,
                            pCodecCtx->height,
                            pict.data,
                            pict.linesize);

                    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);
            }

            SDL_PollEvent(&event);
            switch(event.type) {
                case SDL_QUIT:
                    quit = 1;
                    SDL_Quit();
                    exit(0);
                    break;
                default:
                    break;
            }
        }

        av_free(pFrame);

        avcodec_close(pCodecCtx);

        av_close_input_file(pFormatCtx);

        return 0;
    }