ffmpeg 0.6.3 能用的tutorial04

编译命令：
gcc -o tutorial04 tutorial04.c -lavformat -lavcodec -lz -lm -lswscale `sdl-config --cflags --libs`

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

#include <stdio.h>
#include <math.h>

#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIOQ_SIZE (5*16*1024)
#define MAX_VIDEOQ_SIZE (5*256*1024)
#define FF_ALLOC_EVENT (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)
#define VIDEO_PICTURE_QUEUE_SIZE 1

static struct SwsContext *img_convert_ctx;

typedef struct PacketQueue {
    AVPacketList *first_pkt, *last_pkt;
    int nb_packets;
    int size;
    SDL_mutex *mutex;
    SDL_cond *cond;
} PacketQueue;

typedef struct VideoPicture {
    SDL_Overlay *bmp;
    int width, height;
    int allocated;
} VideoPicture;

typedef struct VideoState {
    AVFormatContext *pFormatCtx;
    int     videoStream, audioStream;
    AVStream    *audio_st;
    PacketQueue audioq;
    uint8_t     audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3)/2];
    unsigned int    audio_buf_size;
    unsigned int    audio_buf_index;
    AVPacket    audio_pkt;
    uint8_t     *audio_pkt_data;
    int     *audio_pkt_size;
    AVStream    *video_st;
    PacketQueue videoq;

    VideoPicture    pictq[VIDEO_PICTURE_QUEUE_SIZE];
    int     pictq_size, pictq_rindex, pictq_windex;
    SDL_mutex   *pictq_mutex;
    SDL_cond    *pictq_cond;

    SDL_Thread  *parse_tid;
    SDL_Thread  *video_tid;

    char        filename[1024];
    int     quit;
} VideoState;

SDL_Surface *screen;

VideoState *global_video_state;

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 (global_video_state->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_decodec_frame(VideoState *is, uint8_t *audio_buf, int buf_size) {
    int len1, data_size;
    AVPacket *pkt = &is->audio_pkt;

    for (;;) {
        while(is->audio_pkt_size > 0) {
            data_size = buf_size;
            len1 = avcodec_decode_audio2(is->audio_st->codec,
                                (int16_t*)audio_buf, &data_size,
                            is->audio_pkt_data, is->audio_pkt_size);
            if (len1 < 0) {
                is->audio_pkt_size = 0;
                break;
            }
            is->audio_pkt_data += len1;
            is->audio_pkt_size -= len1;
            if (data_size <= 0) {
                continue;
            }
            return data_size;
        }
        if (pkt->data) {
            av_free_packet(pkt);
        }
        if (is->quit) {
            return -1;
        }

        if (packet_queue_get(&is->audioq, pkt, 1) < 0) {
            return -1;
        }
        is->audio_pkt_data = pkt->data;
        is->audio_pkt_size = pkt->size;
    }
}

void audio_callback(void *userdata, Uint8 *stream, int len) {
    VideoState *is = (VideoState *)userdata;
    int len1, audio_size;

    while(len > 0) {
        if (is->audio_buf_index >= is->audio_buf_size) {
            audio_size = audio_decodec_frame(is, is->audio_buf, sizeof(is->audio_buf));
            if (audio_size < 0) {
                is->audio_buf_size = 1024;
                memset(is->audio_buf, 0, is->audio_buf_size);
            } else {
                is->audio_buf_size = audio_size;
            }
            is->audio_buf_index = 0;
        }
        len1 = is->audio_buf_size - is->audio_buf_index;
        if (len1 > len) {
            len1 = len;
        }
        memcpy(stream, (uint8_t*)is->audio_buf + is->audio_buf_index, len1);
        len -= len1;
        stream += len1;
        is->audio_buf_index += len1;
    }
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque) {
    SDL_Event event;
    event.type = FF_REFRESH_EVENT;
    event.user.data1 = opaque;
    SDL_PushEvent(&event);
    return 0;
}

static void schedule_refresh(VideoState *is, int delay) {
    SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is) {
    SDL_Rect rect;
    VideoPicture *vp;
    AVPicture pict;
    float aspect_ratio;
    int w, h, x, y;
    int i;

    vp = &is->pictq[is->pictq_rindex];
    if (vp->bmp) {
        if (is->video_st->codec->sample_aspect_ratio.num == 0) {
            aspect_ratio = 0;
        } else {
            aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio)*is->video_st->codec->width / is->video_st->codec->height;
        }
        if (aspect_ratio <= 0.0) {
            aspect_ratio = (float)is->video_st->codec->width / (float)is->video_st->codec->height;
        }
        h = screen->h;
        w = ((int)rint(h*aspect_ratio)) & -3;
        if (w > screen->w) {
            w = screen->w;
            h = ((int)rint(w / aspect_ratio)) & -3;
        }
        x = (screen->w - w) / 2;
        y = (screen->h - h) / 2;

        rect.x = x;
        rect.y = y;
        rect.w = w;
        rect.h = h;
        SDL_DisplayYUVOverlay(vp->bmp, &rect);
    }
}

void video_refresh_timer(void *userdata) {
    VideoState *is = (VideoState *)userdata;
    VideoPicture *vp;

    if (is->video_st) {
        if (is->pictq_size == 0) {
            schedule_refresh(is ,1);
        } else {
            vp = &is->pictq[is->pictq_rindex];
            schedule_refresh(is, 80);
            video_display(is);
            if (++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE) {
                is->pictq_rindex = 0;
            }
            SDL_LockMutex(is->pictq_mutex);
            is->pictq_size--;
            SDL_CondSignal(is->pictq_cond);
            SDL_UnlockMutex(is->pictq_mutex);
        }
    } else {
        schedule_refresh(is, 100);
    }
}

void alloc_picture(void *userdata) {
    VideoState *is = (VideoState *)userdata;
    VideoPicture *vp;

    vp = &is->pictq[is->pictq_windex];
    if (vp->bmp) {
        SDL_FreeYUVOverlay(vp->bmp);
    }

    vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,
                           is->video_st->codec->height,
                       SDL_YV12_OVERLAY,
                       screen);
    vp->width = is->video_st->codec->width;
    vp->height = is->video_st->codec->height;

    SDL_LockMutex(is->pictq_mutex);
    vp->allocated = 1;
    SDL_CondSignal(is->pictq_cond);
    SDL_UnlockMutex(is->pictq_mutex);
}

int queue_picture(VideoState *is, AVFrame *pFrame) {
    VideoPicture *vp;
    int dst_pix_fmt;
    AVPicture pict;

    SDL_LockMutex(is->pictq_mutex);
    while (is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE && !is->quit) {
        SDL_CondWait(is->pictq_cond, is->pictq_mutex);
    }
    SDL_UnlockMutex(is->pictq_mutex);

    if (is->quit) {
        return -1;
    }

    vp = &is->pictq[is->pictq_windex];

    if (!vp->bmp || vp->width != is->video_st->codec->width || vp->height != is->video_st->codec->height) {
        SDL_Event event;

        vp->allocated = 0;
        event.type = FF_ALLOC_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);

        SDL_LockMutex(is->pictq_mutex);
        while (!vp->allocated && !is->quit) {
            SDL_CondWait(is->pictq_cond, is->pictq_mutex);
        }
        SDL_UnlockMutex(is->pictq_mutex);
        if (is->quit) {
            return -1;
        }
    }

    if (vp->bmp) {
        SDL_LockYUVOverlay(vp->bmp);
        dst_pix_fmt = PIX_FMT_YUV420P;

        pict.data[0] = vp->bmp->pixels[0];
        pict.data[1] = vp->bmp->pixels[2];
        pict.data[2] = vp->bmp->pixels[1];

        pict.linesize[0] = vp->bmp->pitches[0];
        pict.linesize[1] = vp->bmp->pitches[2];
        pict.linesize[2] = vp->bmp->pitches[1];

        //*
        sws_scale(img_convert_ctx,
                  pFrame->data,
              pFrame->linesize, 0,
              is->video_st->codec->height,
              pict.data,
              pict.linesize);
        //*/

        SDL_UnlockYUVOverlay(vp->bmp);
        if (++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE) {
            is->pictq_windex = 0;
        }
        SDL_LockMutex(is->pictq_mutex);
        is->pictq_size++;
        SDL_UnlockMutex(is->pictq_mutex);
    }
    return 0;
}

int video_thread(void *arg) {
    VideoState *is = (VideoState *)arg;
    AVPacket pkt1, *packet = &pkt1;
    int len1, frameFinished;
    AVFrame *pFrame;

    pFrame = avcodec_alloc_frame();

    for (;;) {
        if (packet_queue_get(&is->videoq, packet, 1) < 0) {
            break;
        }
        len1 = avcodec_decode_video(is->video_st->codec, pFrame, &frameFinished, packet->data, packet->size);

        if (frameFinished) {
            if (queue_picture(is, pFrame) < 0) {
                break;
            }
        }
        av_free_packet(packet);
    }
    av_free(pFrame);
    return 0;
}

int stream_component_open(VideoState *is, int stream_index) {
    AVFormatContext *pFormatCtx = is->pFormatCtx;
    AVCodecContext *codecCtx;
    AVCodec *codec;
    SDL_AudioSpec wanted_spec, spec;

    if (stream_index < 0 || stream_index >= pFormatCtx->nb_streams) {
        return -1;
    }

    codecCtx = pFormatCtx->streams[stream_index]->codec;
    ///*
    img_convert_ctx = sws_getContext(codecCtx->width,
            codecCtx->height,
            codecCtx->pix_fmt,
            codecCtx->width,
            codecCtx->height,
            PIX_FMT_YUV420P,
            SWS_BICUBIC,
            NULL, NULL, NULL);
            //*/

    if (codecCtx->codec_type == CODEC_TYPE_AUDIO) {
        wanted_spec.freq = codecCtx->sample_rate;
        wanted_spec.format = AUDIO_S16SYS;
        wanted_spec.channels = codecCtx->channels;
        wanted_spec.silence = 0;
        wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
        wanted_spec.callback = audio_callback;
        wanted_spec.userdata = is;

        if (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
            fprintf(stderr,"SDL_OpenAudio: %s\n", SDL_GetError());
            return -1;
        }
    }
    codec = avcodec_find_decoder(codecCtx->codec_id);
    if (!codec || (avcodec_open(codecCtx, codec)) < 0) {
        fprintf(stderr, "Unsupported codec!\n");
        return -1;
    }

    switch(codecCtx->codec_type) {
        case CODEC_TYPE_AUDIO:
            is->audioStream = stream_index;
            is->audio_st = pFormatCtx->streams[stream_index];
            is->audio_buf_size = 0;
            is->audio_buf_index = 0;
            memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
            packet_queue_init(&is->audioq);
            SDL_PauseAudio(0);
            break;
        case CODEC_TYPE_VIDEO:
            is->videoStream = stream_index;
            is->video_st = pFormatCtx->streams[stream_index];

            packet_queue_init(&is->videoq);
            is->video_tid = SDL_CreateThread(video_thread, is);
            break;
        default:
            break;
    }

}

int decode_interrupt_cb(void) {
    return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg) {
    VideoState *is = (VideoState*)arg;
    AVFormatContext *pFormatCtx;
    AVPacket pkt1, *packet = &pkt1;

    int video_index = -1;
    int audio_index = -1;
    int i;

    is->videoStream = -1;
    is->audioStream = -1;

    global_video_state = is;
    url_set_interrupt_cb(decode_interrupt_cb);
    if (av_open_input_file(&pFormatCtx, is->filename, NULL, 0, NULL) != 0) {
        return -1;
    }
    is->pFormatCtx = pFormatCtx;
    if (av_find_stream_info(pFormatCtx) < 0) {
        return -1;
    }

    dump_format(pFormatCtx, 0, is->filename, 0);

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

    if (audio_index >= 0) {
        stream_component_open(is, audio_index);
    }
    if (video_index >= 0) {
        stream_component_open(is, video_index);
    }

    if (is->videoStream < 0 || is->audioStream < 0) {
        fprintf(stderr, "%s: could not open codecs\n", is->filename);
        goto fail;
    }

    for (;;) {
        if (is->quit) {
            break;
        }
        if (is->audioq.size > MAX_AUDIOQ_SIZE || is->videoq.size > MAX_VIDEOQ_SIZE) {
            SDL_Delay(10);
            continue;
        }
        if (av_read_frame(is->pFormatCtx, packet) < 0) {
            if (url_ferror(&pFormatCtx->pb) == 0) {
                SDL_Delay(100);
                continue;
            } else {
                break;
            }
        }
        if (packet->stream_index == is->videoStream) {
            packet_queue_put(&is->videoq, packet);
        } else if (packet->stream_index == is->audioStream){
            packet_queue_put(&is->audioq, packet);
        } else {
            av_free_packet(packet);
        }
    }
    while (!is->quit) {
        SDL_Delay(100);
    }

fail:
    if (1) {
        SDL_Event event;
        event.type = FF_QUIT_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);
    }
    return 0;
}

int main(int argc, char *argv[]) {
    SDL_Event event;
    VideoState *is;

    is = av_mallocz(sizeof(VideoState));

    if (argc < 2) {
        fprintf(stderr, "Isage: 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);
    }

    screen = SDL_SetVideoMode(640, 480, 24, 0);

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

    av_strlcpy(is->filename, argv[1], sizeof(is->filename));

    is->pictq_mutex = SDL_CreateMutex();
    is->pictq_cond = SDL_CreateCond();

    schedule_refresh(is, 40);

    is->parse_tid = SDL_CreateThread(decode_thread, is);
    if (!is->parse_tid) {
        av_free(is);
        return -1;
    }

    for (;;) {
        SDL_WaitEvent(&event);
        switch(event.type) {
            case FF_QUIT_EVENT:
            case SDL_QUIT:
                is->quit = 1;
                SDL_Quit();
                return 0;
                break;
            case FF_ALLOC_EVENT:
                alloc_picture(event.user.data1);
                break;
            case FF_REFRESH_EVENT:
                video_refresh_timer(event.user.data1);
                break;
            default:
                break;
        }
    }
    return 0;
}