ffplay.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

                                              pts);
               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;
    }
}

/* open a given stream. Return 0 if OK */
static int stream_component_open(VideoState *is, int stream_index)
{
    AVFormatContext *ic = is->ic;
    AVCodecContext *enc;
    AVCodec *codec;
    SDL_AudioSpec wanted_spec, spec;

    if (stream_index < 0 || stream_index >= ic->nb_streams)
        return -1;
    enc = ic->streams[stream_index]->codec;

    /* prepare audio output */
    if (enc->codec_type == CODEC_TYPE_AUDIO) {
        wanted_spec.freq = enc->sample_rate;
        wanted_spec.format = AUDIO_S16SYS;
        /* hack for AC3. XXX: suppress that */
        if (enc->channels > 2)
            enc->channels = 2;
        wanted_spec.channels = enc->channels;
        wanted_spec.silence = 0;
        wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
        wanted_spec.callback = sdl_audio_callback;
        wanted_spec.userdata = is;
        if (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
            fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
            return -1;
        }
        is->audio_hw_buf_size = spec.size;
    }

    codec = avcodec_find_decoder(enc->codec_id);
    enc->debug_mv = debug_mv;
    enc->debug = debug;
    enc->workaround_bugs = workaround_bugs;
    enc->lowres = lowres;
    if(lowres) enc->flags |= CODEC_FLAG_EMU_EDGE;
    enc->idct_algo= idct;
    if(fast) enc->flags2 |= CODEC_FLAG2_FAST;
    enc->skip_frame= skip_frame;
    enc->skip_idct= skip_idct;
    enc->skip_loop_filter= skip_loop_filter;
    enc->error_resilience= error_resilience;
    enc->error_concealment= error_concealment;
    if (!codec ||
        avcodec_open(enc, codec) < 0)
        return -1;
    if(thread_count>1)
        avcodec_thread_init(enc, thread_count);
    enc->thread_count= thread_count;
    switch(enc->codec_type) {
    case CODEC_TYPE_AUDIO:
        is->audio_stream = stream_index;
        is->audio_st = ic->streams[stream_index];
        is->audio_buf_size = 0;
        is->audio_buf_index = 0;

        /* init averaging filter */
        is->audio_diff_avg_coef = exp(log(0.01) / AUDIO_DIFF_AVG_NB);
        is->audio_diff_avg_count = 0;
        /* since we do not have a precise anough audio fifo fullness,
           we correct audio sync only if larger than this threshold */
        is->audio_diff_threshold = 2.0 * SDL_AUDIO_BUFFER_SIZE / enc->sample_rate;

        memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
        packet_queue_init(&is->audioq);
        SDL_PauseAudio(0);
        break;
    case CODEC_TYPE_VIDEO:
        is->video_stream = stream_index;
        is->video_st = ic->streams[stream_index];

        is->frame_last_delay = 40e-3;
        is->frame_timer = (double)av_gettime() / 1000000.0;
        is->video_current_pts_time = av_gettime();

        packet_queue_init(&is->videoq);
        is->video_tid = SDL_CreateThread(video_thread, is);

        enc->    get_buffer=     my_get_buffer;
        enc->release_buffer= my_release_buffer;
        break;
    case CODEC_TYPE_SUBTITLE:
        is->subtitle_stream = stream_index;
        is->subtitle_st = ic->streams[stream_index];
        packet_queue_init(&is->subtitleq);

        is->subtitle_tid = SDL_CreateThread(subtitle_thread, is);
        break;
    default:
        break;
    }
    return 0;
}

static void stream_component_close(VideoState *is, int stream_index)
{
    AVFormatContext *ic = is->ic;
    AVCodecContext *enc;

    if (stream_index < 0 || stream_index >= ic->nb_streams)
        return;
    enc = ic->streams[stream_index]->codec;

    switch(enc->codec_type) {
    case CODEC_TYPE_AUDIO:
        packet_queue_abort(&is->audioq);

        SDL_CloseAudio();

        packet_queue_end(&is->audioq);
        break;
    case CODEC_TYPE_VIDEO:
        packet_queue_abort(&is->videoq);

        /* note: we also signal this mutex to make sure we deblock the
           video thread in all cases */
        SDL_LockMutex(is->pictq_mutex);
        SDL_CondSignal(is->pictq_cond);
        SDL_UnlockMutex(is->pictq_mutex);

        SDL_WaitThread(is->video_tid, NULL);

        packet_queue_end(&is->videoq);
        break;
    case CODEC_TYPE_SUBTITLE:
        packet_queue_abort(&is->subtitleq);

        /* note: we also signal this mutex to make sure we deblock the
           video thread in all cases */
        SDL_LockMutex(is->subpq_mutex);
        is->subtitle_stream_changed = 1;

        SDL_CondSignal(is->subpq_cond);
        SDL_UnlockMutex(is->subpq_mutex);

        SDL_WaitThread(is->subtitle_tid, NULL);

        packet_queue_end(&is->subtitleq);
        break;
    default:
        break;
    }

    avcodec_close(enc);
    switch(enc->codec_type) {
    case CODEC_TYPE_AUDIO:
        is->audio_st = NULL;
        is->audio_stream = -1;
        break;
    case CODEC_TYPE_VIDEO:
        is->video_st = NULL;
        is->video_stream = -1;
        break;
    case CODEC_TYPE_SUBTITLE:
        is->subtitle_st = NULL;
        is->subtitle_stream = -1;
        break;
    default:
        break;
    }
}

static void dump_stream_info(const AVFormatContext *s)
{
    if (s->track != 0)
        fprintf(stderr, "Track: %d\n", s->track);
    if (s->title[0] != '\0')
        fprintf(stderr, "Title: %s\n", s->title);
    if (s->author[0] != '\0')
        fprintf(stderr, "Author: %s\n", s->author);
    if (s->copyright[0] != '\0')
        fprintf(stderr, "Copyright: %s\n", s->copyright);
    if (s->comment[0] != '\0')
        fprintf(stderr, "Comment: %s\n", s->comment);
    if (s->album[0] != '\0')
        fprintf(stderr, "Album: %s\n", s->album);
    if (s->year != 0)
        fprintf(stderr, "Year: %d\n", s->year);
    if (s->genre[0] != '\0')
        fprintf(stderr, "Genre: %s\n", s->genre);
}

/* since we have only one decoding thread, we can use a global
   variable instead of a thread local variable */
static VideoState *global_video_state;

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

/* this thread gets the stream from the disk or the network */
static int decode_thread(void *arg)
{
    VideoState *is = arg;
    AVFormatContext *ic;
    int err, i, ret, video_index, audio_index;
    AVPacket pkt1, *pkt = &pkt1;
    AVFormatParameters params, *ap = &params;

    video_index = -1;
    audio_index = -1;
    is->video_stream = -1;
    is->audio_stream = -1;
    is->subtitle_stream = -1;

    global_video_state = is;
    url_set_interrupt_cb(decode_interrupt_cb);

    memset(ap, 0, sizeof(*ap));

    ap->width = frame_width;
    ap->height= frame_height;
    ap->time_base= (AVRational){1, 25};
    ap->pix_fmt = frame_pix_fmt;

    err = av_open_input_file(&ic, is->filename, is->iformat, 0, ap);
    if (err < 0) {
        print_error(is->filename, err);
        ret = -1;
        goto fail;
    }
    is->ic = ic;

    if(genpts)
        ic->flags |= AVFMT_FLAG_GENPTS;

    err = av_find_stream_info(ic);
    if (err < 0) {
        fprintf(stderr, "%s: could not find codec parameters\n", is->filename);
        ret = -1;
        goto fail;
    }
    ic->pb.eof_reached= 0; //FIXME hack, ffplay maybe should not use url_feof() to test for the end

    /* if seeking requested, we execute it */
    if (start_time != AV_NOPTS_VALUE) {
        int64_t timestamp;

        timestamp = start_time;
        /* add the stream start time */
        if (ic->start_time != AV_NOPTS_VALUE)
            timestamp += ic->start_time;
        ret = av_seek_frame(ic, -1, timestamp, AVSEEK_FLAG_BACKWARD);
        if (ret < 0) {
            fprintf(stderr, "%s: could not seek to position %0.3f\n",
                    is->filename, (double)timestamp / AV_TIME_BASE);
        }
    }

    for(i = 0; i < ic->nb_streams; i++) {
        AVCodecContext *enc = ic->streams[i]->codec;
        switch(enc->codec_type) {
        case CODEC_TYPE_AUDIO:
            if ((audio_index < 0 || wanted_audio_stream-- > 0) && !audio_disable)
                audio_index = i;
            break;
        case CODEC_TYPE_VIDEO:
            if ((video_index < 0 || wanted_video_stream-- > 0) && !video_disable)
                video_index = i;
            break;
        default:
            break;
        }
    }
    if (show_status) {
        dump_format(ic, 0, is->filename, 0);
        dump_stream_info(ic);
    }

    /* open the streams */
    if (audio_index >= 0) {
        stream_component_open(is, audio_index);
    }

    if (video_index >= 0) {
        stream_component_open(is, video_index);
    } else {
        if (!display_disable)
            is->show_audio = 1;
    }

    if (is->video_stream < 0 && is->audio_stream < 0) {
        fprintf(stderr, "%s: could not open codecs\n", is->filename);
        ret = -1;
        goto fail;
    }

    for(;;) {
        if (is->abort_request)
            break;
        if (is->paused != is->last_paused) {
            is->last_paused = is->paused;
            if (is->paused)
                av_read_pause(ic);
            else
                av_read_play(ic);
        }
#ifdef CONFIG_RTSP_DEMUXER
        if (is->paused && !strcmp(ic->iformat->name, "rtsp")) {
            /* wait 10 ms to avoid trying to get another packet */
            /* XXX: horrible */
            SDL_Delay(10);
            continue;
        }
#endif
        if (is->seek_req) {
            int stream_index= -1;
            int64_t seek_target= is->seek_pos;

            if     (is->   video_stream >= 0) stream_index= is->   video_stream;
            else if(is->   audio_stream >= 0) stream_index= is->   audio_stream;
            else if(is->subtitle_stream >= 0) stream_index= is->subtitle_stream;

            if(stream_index>=0){
                seek_target= av_rescale_q(seek_target, AV_TIME_BASE_Q, ic->streams[stream_index]->time_base);
            }

            ret = av_seek_frame(is->ic, stream_index, seek_target, is->seek_flags);
            if (ret < 0) {
                fprintf(stderr, "%s: error while seeking\n", is->ic->filename);
            }else{
                if (is->audio_stream >= 0) {
                    packet_queue_flush(&is->audioq);
                    packet_queue_put(&is->audioq, &flush_pkt);
                }
                if (is->subtitle_stream >= 0) {
                    packet_queue_flush(&is->subtitleq);
                    packet_queue_put(&is->subtitleq, &flush_pkt);
                }
                if (is->video_stream >= 0) {
                    packet_queue_flush(&is->videoq);
                    packet_queue_put(&is->videoq, &flush_pkt);
                }
            }
            is->seek_req = 0;
        }

        /* if the queue are full, no need to read more */
        if (is->audioq.size > MAX_AUDIOQ_SIZE ||
            is->videoq.size > MAX_VIDEOQ_SIZE ||
            is->subtitleq.size > MAX_SUBTITLEQ_SIZE ||
            url_feof(&ic->pb)) {
            /* wait 10 ms */
            SDL_Delay(10);
            continue;
        }
        ret = av_read_frame(ic, pkt);
        if (ret < 0) {
            if (url_ferror(&ic->pb) == 0) {
                SDL_Delay(100); /* wait for user event */
                continue;
            } else
                break;
        }
        if (pkt->stream_index == is->audio_stream) {
            packet_queue_put(&is->audioq, pkt);
        } else if (pkt->stream_index == is->video_stream) {
            packet_queue_put(&is->videoq, pkt);
        } else if (pkt->stream_index == is->subtitle_stream) {
            packet_queue_put(&is->subtitleq, pkt);
        } else {
            av_free_packet(pkt);
        }
    }
    /* wait until the end */
    while (!is->abort_request) {
        SDL_Delay(100);
    }

    ret = 0;
 fail:
    /* disable interrupting */
    global_video_state = NULL;

    /* close each stream */
    if (is->audio_stream >= 0)
        stream_component_close(is, is->audio_stream);
    if (is->video_stream >= 0)
        stream_component_close(is, is->video_stream);
    if (is->subtitle_stream >= 0)
        stream_component_close(is, is->subtitle_stream);
    if (is->ic) {
        av_close_input_file(is->ic);
        is->ic = NULL; /* safety */
    }
    url_set_interrupt_cb(NULL);

    if (ret != 0) {
        SDL_Event event;

        event.type = FF_QUIT_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);
    }