ffplay.c

                avg_diff = is->audio_diff_cum * (1.0 - is->audio_diff_avg_coef);

                if (fabs(avg_diff) >= is->audio_diff_threshold) {
                    wanted_size = samples_size + ((int)(diff * is->audio_st->codec->sample_rate) * n);
                    nb_samples = samples_size / n;

                    min_size = ((nb_samples * (100 - SAMPLE_CORRECTION_PERCENT_MAX)) / 100) * n;
                    max_size = ((nb_samples * (100 + SAMPLE_CORRECTION_PERCENT_MAX)) / 100) * n;
                    if (wanted_size < min_size)
                        wanted_size = min_size;
                    else if (wanted_size > max_size)
                        wanted_size = max_size;

                    /* add or remove samples to correction the synchro */
                    if (wanted_size < samples_size) {
                        /* remove samples */
                        samples_size = wanted_size;
                    } else if (wanted_size > samples_size) {
                        uint8_t *samples_end, *q;
                        int nb;

                        /* add samples */
                        nb = (samples_size - wanted_size);
                        samples_end = (uint8_t *)samples + samples_size - n;
                        q = samples_end + n;
                        while (nb > 0) {
                            memcpy(q, samples_end, n);
                            q += n;
                            nb -= n;
                        }
                        samples_size = wanted_size;
                    }
                }
#if 0
                printf("diff=%f adiff=%f sample_diff=%d apts=%0.3f vpts=%0.3f %f\n",
                       diff, avg_diff, samples_size - samples_size1,
                       is->audio_clock, is->video_clock, is->audio_diff_threshold);
#endif
            }
        } else {
            /* too big difference : may be initial PTS errors, so
               reset A-V filter */
            is->audio_diff_avg_count = 0;
            is->audio_diff_cum = 0;
        }
    }

    return samples_size;
}

/* decode one audio frame and returns its uncompressed size */
static int audio_decode_frame(VideoState *is, double *pts_ptr)
{
    AVPacket *pkt_temp = &is->audio_pkt_temp;
    AVPacket *pkt = &is->audio_pkt;
    AVCodecContext *dec= is->audio_st->codec;
    int n, len1, data_size;
    double pts;

    for(;;) {
        /* NOTE: the audio packet can contain several frames */
        while (pkt_temp->size > 0) {
            data_size = sizeof(is->audio_buf1);
            len1 = avcodec_decode_audio3(dec,
                                        (int16_t *)is->audio_buf1, &data_size,
                                        pkt_temp);
            if (len1 < 0) {
                /* if error, we skip the frame */
                pkt_temp->size = 0;
                break;
            }

            pkt_temp->data += len1;
            pkt_temp->size -= len1;
            if (data_size <= 0)
                continue;

            if (dec->sample_fmt != is->audio_src_fmt) {
                if (is->reformat_ctx)
                    av_audio_convert_free(is->reformat_ctx);
                is->reformat_ctx= av_audio_convert_alloc(SAMPLE_FMT_S16, 1,
                                                         dec->sample_fmt, 1, NULL, 0);
                if (!is->reformat_ctx) {
                    fprintf(stderr, "Cannot convert %s sample format to %s sample format\n",
                        avcodec_get_sample_fmt_name(dec->sample_fmt),
                        avcodec_get_sample_fmt_name(SAMPLE_FMT_S16));
                        break;
                }
                is->audio_src_fmt= dec->sample_fmt;
            }

            if (is->reformat_ctx) {
                const void *ibuf[6]= {is->audio_buf1};
                void *obuf[6]= {is->audio_buf2};
                int istride[6]= {av_get_bits_per_sample_format(dec->sample_fmt)/8};
                int ostride[6]= {2};
                int len= data_size/istride[0];
                if (av_audio_convert(is->reformat_ctx, obuf, ostride, ibuf, istride, len)<0) {
                    printf("av_audio_convert() failed\n");
                    break;
                }
                is->audio_buf= is->audio_buf2;
                /* FIXME: existing code assume that data_size equals framesize*channels*2
                          remove this legacy cruft */
                data_size= len*2;
            }else{
                is->audio_buf= is->audio_buf1;
            }

            /* if no pts, then compute it */
            pts = is->audio_clock;
            *pts_ptr = pts;
            n = 2 * dec->channels;
            is->audio_clock += (double)data_size /
                (double)(n * dec->sample_rate);
#if defined(DEBUG_SYNC)
            {
                static double last_clock;
                printf("audio: delay=%0.3f clock=%0.3f pts=%0.3f\n",
                       is->audio_clock - last_clock,
                       is->audio_clock, pts);
                last_clock = is->audio_clock;
            }
#endif
            return data_size;
        }

        /* free the current packet */
        if (pkt->data)
            av_free_packet(pkt);

        if (is->paused || is->audioq.abort_request) {
            return -1;
        }

        /* read next packet */
        if (packet_queue_get(&is->audioq, pkt, 1) < 0)
            return -1;
        if(pkt->data == flush_pkt.data){
            avcodec_flush_buffers(dec);
            continue;
        }

        pkt_temp->data = pkt->data;
        pkt_temp->size = pkt->size;

        /* if update the audio clock with the pts */
        if (pkt->pts != AV_NOPTS_VALUE) {
            is->audio_clock = av_q2d(is->audio_st->time_base)*pkt->pts;
        }
    }
}

/* get the current audio output buffer size, in samples. With SDL, we
   cannot have a precise information */
static int audio_write_get_buf_size(VideoState *is)
{
    return is->audio_buf_size - is->audio_buf_index;
}


/* prepare a new audio buffer */
static void sdl_audio_callback(void *opaque, Uint8 *stream, int len)
{
    VideoState *is = opaque;
    int audio_size, len1;
    double pts;

    audio_callback_time = av_gettime();

    while (len > 0) {
        if (is->audio_buf_index >= is->audio_buf_size) {
           audio_size = audio_decode_frame(is, &pts);
           if (audio_size < 0) {
                /* if error, just output silence */
               is->audio_buf = is->audio_buf1;
               is->audio_buf_size = 1024;
               memset(is->audio_buf, 0, is->audio_buf_size);
           } else {
               if (is->show_audio)
                   update_sample_display(is, (int16_t *)is->audio_buf, audio_size);
               audio_size = synchronize_audio(is, (int16_t *)is->audio_buf, audio_size,
                                              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 *avctx;
    AVCodec *codec;
    SDL_AudioSpec wanted_spec, spec;

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

    /* prepare audio output */
    if (avctx->codec_type == AVMEDIA_TYPE_AUDIO) {
        if (avctx->channels > 0) {
            avctx->request_channels = FFMIN(2, avctx->channels);
        } else {
            avctx->request_channels = 2;
        }
    }

    codec = avcodec_find_decoder(avctx->codec_id);
    avctx->debug_mv = debug_mv;
    avctx->debug = debug;
    avctx->workaround_bugs = workaround_bugs;
    avctx->lowres = lowres;
    if(lowres) avctx->flags |= CODEC_FLAG_EMU_EDGE;
    avctx->idct_algo= idct;
    if(fast) avctx->flags2 |= CODEC_FLAG2_FAST;
    avctx->skip_frame= skip_frame;
    avctx->skip_idct= skip_idct;
    avctx->skip_loop_filter= skip_loop_filter;
    avctx->error_recognition= error_recognition;
    avctx->error_concealment= error_concealment;
    avcodec_thread_init(avctx, thread_count);

    set_context_opts(avctx, avcodec_opts[avctx->codec_type], 0);

    if (!codec ||
        avcodec_open(avctx, codec) < 0)
        return -1;

    /* prepare audio output */
    if (avctx->codec_type == AVMEDIA_TYPE_AUDIO) {
        wanted_spec.freq = avctx->sample_rate;
        wanted_spec.format = AUDIO_S16SYS;
        wanted_spec.channels = avctx->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;
        is->audio_src_fmt= SAMPLE_FMT_S16;
    }

    ic->streams[stream_index]->discard = AVDISCARD_DEFAULT;
    switch(avctx->codec_type) {
    case AVMEDIA_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 / avctx->sample_rate;

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

//        is->video_current_pts_time = av_gettime();

        packet_queue_init(&is->videoq);
        is->video_tid = SDL_CreateThread(video_thread, is);
        break;
    case AVMEDIA_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 *avctx;

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

    switch(avctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        packet_queue_abort(&is->audioq);

        SDL_CloseAudio();

        packet_queue_end(&is->audioq);
        if (is->reformat_ctx)
            av_audio_convert_free(is->reformat_ctx);
        is->reformat_ctx = NULL;
        break;
    case AVMEDIA_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 AVMEDIA_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;
    }

    ic->streams[stream_index]->discard = AVDISCARD_ALL;
    avcodec_close(avctx);
    switch(avctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        is->audio_st = NULL;
        is->audio_stream = -1;
        break;
    case AVMEDIA_TYPE_VIDEO:
        is->video_st = NULL;
        is->video_stream = -1;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        is->subtitle_st = NULL;
        is->subtitle_stream = -1;
        break;
    default:
        break;
    }
}

/* 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;
    int st_index[AVMEDIA_TYPE_NB];
    int st_count[AVMEDIA_TYPE_NB]={0};
    int st_best_packet_count[AVMEDIA_TYPE_NB];
    AVPacket pkt1, *pkt = &pkt1;
    AVFormatParameters params, *ap = &params;
    int eof=0;
    int pkt_in_play_range = 0;

    ic = avformat_alloc_context();

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

    set_context_opts(ic, avformat_opts, AV_OPT_FLAG_DECODING_PARAM);

    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;
    }
    if(ic->pb)
        ic->pb->eof_reached= 0; //FIXME hack, ffplay maybe should not use url_feof() to test for the end

    if(seek_by_bytes<0)
        seek_by_bytes= !!(ic->iformat->flags & AVFMT_TS_DISCONT);

    /* 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 = avformat_seek_file(ic, -1, INT64_MIN, timestamp, INT64_MAX, 0);
        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++) {
        AVStream *st= ic->streams[i];
        AVCodecContext *avctx = st->codec;
        ic->streams[i]->discard = AVDISCARD_ALL;
        if(avctx->codec_type >= (unsigned)AVMEDIA_TYPE_NB)
            continue;
        if(st_count[avctx->codec_type]++ != wanted_stream[avctx->codec_type] && wanted_stream[avctx->codec_type] >= 0)
            continue;

        if(st_best_packet_count[avctx->codec_type] >= st->codec_info_nb_frames)
            continue;
        st_best_packet_count[avctx->codec_type]= st->codec_info_nb_frames;

        switch(avctx->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            if (!audio_disable)
                st_index[AVMEDIA_TYPE_AUDIO] = i;
            break;
        case AVMEDIA_TYPE_VIDEO:
        case AVMEDIA_TYPE_SUBTITLE:
            if (!video_disable)
                st_index[avctx->codec_type] = i;
            break;
        default:
            break;
        }
    }
    if (show_status) {
        dump_format(ic, 0, is->filename, 0);
    }

    /* open the streams */
    if (st_index[AVMEDIA_TYPE_AUDIO] >= 0) {
        stream_component_open(is, st_index[AVMEDIA_TYPE_AUDIO]);
    }

    ret=-1;
    if (st_index[AVMEDIA_TYPE_VIDEO] >= 0) {
        ret= stream_component_open(is, st_index[AVMEDIA_TYPE_VIDEO]);
    }
    is->refresh_tid = SDL_CreateThread(refresh_thread, is);
    if(ret<0) {
        if (!display_disable)
            is->show_audio = 2;
    }

    if (st_index[AVMEDIA_TYPE_SUBTITLE] >= 0) {
        stream_component_open(is, st_index[AVMEDIA_TYPE_SUBTITLE]);
    }

    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)
                is->read_pause_return= av_read_pause(ic);
            else
                av_read_play(ic);
        }
#if 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) {
            int64_t seek_target= is->seek_pos;
            int64_t seek_min= is->seek_rel > 0 ? seek_target - is->seek_rel + 2: INT64_MIN;
            int64_t seek_max= is->seek_rel < 0 ? seek_target - is->seek_rel - 2: INT64_MAX;
//FIXME the +-2 is due to rounding being not done in the correct direction in generation
//      of the seek_pos/seek_rel variables

            ret = avformat_seek_file(is->ic, -1, seek_min, seek_target, seek_max, 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;
            eof= 0;
        }

        /* if the queue are full, no need to read more */
        if (   is->audioq.size + is->videoq.size + is->subtitleq.size > MAX_QUEUE_SIZE
            || (   (is->audioq   .size  > MIN_AUDIOQ_SIZE || is->audio_stream<0)
                && (is->videoq   .nb_packets > MIN_FRAMES || is->video_stream<0)
                && (is->subtitleq.nb_packets > MIN_FRAMES || is->subtitle_stream<0))) {
            /* wait 10 ms */
            SDL_Delay(10);
            continue;
        }
        if(url_feof(ic->pb) || eof) {
            if(is->video_stream >= 0){
                av_init_packet(pkt);
                pkt->data=NULL;
                pkt->size=0;
                pkt->stream_index= is->video_stream;
                packet_queue_put(&is->videoq, pkt);
            }
            SDL_Delay(10);
            if(is->audioq.size + is->videoq.size + is->subtitleq.size ==0){
                if(loop!=1 && (!loop || --loop)){
                    stream_seek(cur_stream, start_time != AV_NOPTS_VALUE ? start_time : 0, 0, 0);
                }else if(autoexit){
                    ret=AVERROR_EOF;
                    goto fail;
                }
            }
            continue;
        }
        ret = av_read_frame(ic, pkt);
        if (ret < 0) {
            if (ret == AVERROR_EOF)
                eof=1;
            if (url_ferror(ic->pb))
                break;
            SDL_Delay(100); /* wait for user event */
            continue;
        }
        /* check if packet is in play range specified by user, then queue, otherwise discard */
        pkt_in_play_range = duration == AV_NOPTS_VALUE ||
                (pkt->pts - ic->streams[pkt->stream_index]->start_time) *
                av_q2d(ic->streams[pkt->stream_index]->time_base) -
                (double)(start_time != AV_NOPTS_VALUE ? start_time : 0)/1000000
                <= ((double)duration/1000000);
        if (pkt->stream_index == is->audio_stream && pkt_in_play_range) {
            packet_queue_put(&is->audioq, pkt);
        } else if (pkt->stream_index == is->video_stream && pkt_in_play_range) {
            packet_queue_put(&is->videoq, pkt);
        } else if (pkt->stream_index == is->subtitle_stream && pkt_in_play_range) {
            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);
    }
    return 0;
}

static VideoState *stream_open(const char *filename, AVInputFormat *iformat)
{
    VideoState *is;

    is = av_mallocz(sizeof(VideoState));
    if (!is)
        return NULL;
    av_strlcpy(is->filename, filename, sizeof(is->filename));
    is->iformat = iformat;
    is->ytop = 0;
    is->xleft = 0;

    /* start video display */
    is->pictq_mutex = SDL_CreateMutex();
    is->pictq_cond = SDL_CreateCond();

    is->subpq_mutex = SDL_CreateMutex();
    is->subpq_cond = SDL_CreateCond();

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

static void stream_close(VideoState *is)
{
    VideoPicture *vp;
    int i;
    /* XXX: use a special url_shutdown call to abort parse cleanly */
    is->abort_request = 1;
    SDL_WaitThread(is->parse_tid, NULL);
    SDL_WaitThread(is->refresh_tid, NULL);

    /* free all pictures */
    for(i=0;i<VIDEO_PICTURE_QUEUE_SIZE; i++) {
        vp = &is->pictq[i];
#if CONFIG_AVFILTER
        if (vp->picref) {
            avfilter_unref_pic(vp->picref);
            vp->picref = NULL;
        }
#endif
        if (vp->bmp) {
            SDL_FreeYUVOverlay(vp->bmp);
            vp->bmp = NULL;
        }
    }
    SDL_DestroyMutex(is->pictq_mutex);
    SDL_DestroyCond(is->pictq_cond);
    SDL_DestroyMutex(is->subpq_mutex);
    SDL_DestroyCond(is->subpq_cond);
#if !CONFIG_AVFILTER
    if (is->img_convert_ctx)
        sws_freeContext(is->img_convert_ctx);
#endif
    av_free(is);
}

static void stream_cycle_channel(VideoState *is, int codec_type)
{
    AVFormatContext *ic = is->ic;
    int start_index, stream_index;
    AVStream *st;

    if (codec_type == AVMEDIA_TYPE_VIDEO)
        start_index = is->video_stream;
    else if (codec_type == AVMEDIA_TYPE_AUDIO)
        start_index = is->audio_stream;
    else
        start_index = is->subtitle_stream;
    if (start_index < (codec_type == AVMEDIA_TYPE_SUBTITLE ? -1 : 0))
        return;
    stream_index = start_index;
    for(;;) {
        if (++stream_index >= is->ic->nb_streams)
        {
            if (codec_type == AVMEDIA_TYPE_SUBTITLE)
            {
                stream_index = -1;
                goto the_end;
            } else
                stream_index = 0;
        }
        if (stream_index == start_index)
            return;
        st = ic->streams[stream_index];
        if (st->codec->codec_type == codec_type) {
            /* check that parameters are OK */
            switch(codec_type) {
            case AVMEDIA_TYPE_AUDIO:
                if (st->codec->sample_rate != 0 &&
                    st->codec->channels != 0)
                    goto the_end;
                break;
            case AVMEDIA_TYPE_VIDEO:
            case AVMEDIA_TYPE_SUBTITLE:
                goto the_end;
            default:
                break;
            }
        }
    }
 the_end:
    stream_component_close(is, start_index);
    stream_component_open(is, stream_index);
}


static void toggle_full_screen(void)
{
    is_full_screen = !is_full_screen;
    if (!fs_screen_width) {
        /* use default SDL method */
//        SDL_WM_ToggleFullScreen(screen);
    }
    video_open(cur_stream);
}

static void toggle_pause(void)
{
    if (cur_stream)
        stream_pause(cur_stream);
    step = 0;
}

static void step_to_next_frame(void)
{
    if (cur_stream) {
        /* if the stream is paused unpause it, then step */
        if (cur_stream->paused)
            stream_pause(cur_stream);
    }
    step = 1;
}

static void do_exit(void)
{
    int i;
    if (cur_stream) {
        stream_close(cur_stream);
        cur_stream = NULL;
    }
    for (i = 0; i < AVMEDIA_TYPE_NB; i++)
        av_free(avcodec_opts[i]);
    av_free(avformat_opts);
    av_free(sws_opts);
#if CONFIG_AVFILTER
    avfilter_uninit();
#endif
    if (show_status)
        printf("\n");
    SDL_Quit();
    exit(0);
}

static void toggle_audio_display(void)
{
    if (cur_stream) {
        int bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
        cur_stream->show_audio = (cur_stream->show_audio + 1) % 3;
        fill_rectangle(screen,
                    cur_stream->xleft, cur_stream->ytop, cur_stream->width, cur_stream->height,
                    bgcolor);
        SDL_UpdateRect(screen, cur_stream->xleft, cur_stream->ytop, cur_stream->width, cur_stream->height);
    }
}

/* handle an event sent by the GUI */
static void event_loop(void)
{
    SDL_Event event;
    double incr, pos, frac;

    for(;;) {
        double x;
        SDL_WaitEvent(&event);
        switch(event.type) {
        case SDL_KEYDOWN:
            switch(event.key.keysym.sym) {
            case SDLK_ESCAPE:
            case SDLK_q:
                do_exit();
                break;
            case SDLK_f:
                toggle_full_screen();
                break;
            case SDLK_p:
            case SDLK_SPACE:
                toggle_pause();
                break;
            case SDLK_s: //S: Step to next frame
                step_to_next_frame();
                break;
            case SDLK_a:
                if (cur_stream)
                    stream_cycle_channel(cur_stream, AVMEDIA_TYPE_AUDIO);
                break;
            case SDLK_v:
                if (cur_stream)
                    stream_cycle_channel(cur_stream, AVMEDIA_TYPE_VIDEO);
                break;
            case SDLK_t:
                if (cur_stream)
                    stream_cycle_channel(cur_stream, AVMEDIA_TYPE_SUBTITLE);
                break;
            case SDLK_w:
                toggle_audio_display();
                break;
            case SDLK_LEFT:
                incr = -10.0;
                goto do_seek;
            case SDLK_RIGHT:
                incr = 10.0;
                goto do_seek;
            case SDLK_UP:
                incr = 60.0;
                goto do_seek;
            case SDLK_DOWN:
                incr = -60.0;
            do_seek:
                if (cur_stream) {
                    if (seek_by_bytes) {
                        if (cur_stream->video_stream >= 0 && cur_stream->video_current_pos>=0){
                            pos= cur_stream->video_current_pos;
                        }else if(cur_stream->audio_stream >= 0 && cur_stream->audio_pkt.pos>=0){
                            pos= cur_stream->audio_pkt.pos;
                        }else
                            pos = url_ftell(cur_stream->ic->pb);
                        if (cur_stream->ic->bit_rate)
                            incr *= cur_stream->ic->bit_rate / 8.0;
                        else
                            incr *= 180000.0;
                        pos += incr;
                        stream_seek(cur_stream, pos, incr, 1);
                    } else {
                        pos = get_master_clock(cur_stream);
                        pos += incr;
                        stream_seek(cur_stream, (int64_t)(pos * AV_TIME_BASE), (int64_t)(incr * AV_TIME_BASE), 0);
                    }
                }
                break;
            default:
                break;
            }
            break;
        case SDL_MOUSEBUTTONDOWN:
        case SDL_MOUSEMOTION:
            if(event.type ==SDL_MOUSEBUTTONDOWN){
                x= event.button.x;
            }else{
                if(event.motion.state != SDL_PRESSED)
                    break;
                x= event.motion.x;
            }
            if (cur_stream) {
                if(seek_by_bytes || cur_stream->ic->duration<=0){
                    uint64_t size=  url_fsize(cur_stream->ic->pb);
                    stream_seek(cur_stream, size*x/cur_stream->width, 0, 1);
                }else{
                    int64_t ts;
                    int ns, hh, mm, ss;
                    int tns, thh, tmm, tss;
                    tns = cur_stream->ic->duration/1000000LL;
                    thh = tns/3600;
                    tmm = (tns%3600)/60;
                    tss = (tns%60);
                    frac = x/cur_stream->width;
                    ns = frac*tns;
                    hh = ns/3600;
                    mm = (ns%3600)/60;
                    ss = (ns%60);
                    fprintf(stderr, "Seek to %2.0f%% (%2d:%02d:%02d) of total duration (%2d:%02d:%02d)       \n", frac*100,
                            hh, mm, ss, thh, tmm, tss);
                    ts = frac*cur_stream->ic->duration;
                    if (cur_stream->ic->start_time != AV_NOPTS_VALUE)
                        ts += cur_stream->ic->start_time;
                    stream_seek(cur_stream, ts, 0, 0);
                }
            }
            break;
        case SDL_VIDEORESIZE:
            if (cur_stream) {
                screen = SDL_SetVideoMode(event.resize.w, event.resize.h, 0,
                                          SDL_HWSURFACE|SDL_RESIZABLE|SDL_ASYNCBLIT|SDL_HWACCEL);
                screen_width = cur_stream->width = event.resize.w;
                screen_height= cur_stream->height= event.resize.h;
            }
            break;
        case SDL_QUIT:
        case FF_QUIT_EVENT:
            do_exit();
            break;
        case FF_ALLOC_EVENT:
            video_open(event.user.data1);
            alloc_picture(event.user.data1);
            break;
        case FF_REFRESH_EVENT:
            video_refresh_timer(event.user.data1);
            cur_stream->refresh=0;
            break;
        default:
            break;
        }
    }
}

static void opt_frame_size(const char *arg)
{
    if (av_parse_video_frame_size(&frame_width, &frame_height, arg) < 0) {
        fprintf(stderr, "Incorrect frame size\n");
        exit(1);
    }
    if ((frame_width % 2) != 0 || (frame_height % 2) != 0) {
        fprintf(stderr, "Frame size must be a multiple of 2\n");
        exit(1);
    }
}

static int opt_width(const char *opt, const char *arg)
{
    screen_width = parse_number_or_die(opt, arg, OPT_INT64, 1, INT_MAX);
    return 0;
}

static int opt_height(const char *opt, const char *arg)
{
    screen_height = parse_number_or_die(opt, arg, OPT_INT64, 1, INT_MAX);
    return 0;
}

static void opt_format(const char *arg)
{
    file_iformat = av_find_input_format(arg);
    if (!file_iformat) {
        fprintf(stderr, "Unknown input format: %s\n", arg);
        exit(1);
    }
}

static void opt_frame_pix_fmt(const char *arg)
{
    frame_pix_fmt = av_get_pix_fmt(arg);
}

static int opt_sync(const char *opt, const char *arg)
{
    if (!strcmp(arg, "audio"))
        av_sync_type = AV_SYNC_AUDIO_MASTER;
    else if (!strcmp(arg, "video"))
        av_sync_type = AV_SYNC_VIDEO_MASTER;
    else if (!strcmp(arg, "ext"))
        av_sync_type = AV_SYNC_EXTERNAL_CLOCK;
    else {
        fprintf(stderr, "Unknown value for %s: %s\n", opt, arg);
        exit(1);
    }
    return 0;