ffplay.c

    is->paused = !is->paused;
}

static double compute_frame_delay(double frame_current_pts, VideoState *is)
{
    double actual_delay, delay, sync_threshold, ref_clock, diff;

    /* compute nominal delay */
    delay = frame_current_pts - is->frame_last_pts;
    if (delay <= 0 || delay >= 10.0) {
        /* if incorrect delay, use previous one */
        delay = is->frame_last_delay;
    } else {
        is->frame_last_delay = delay;
    }
    is->frame_last_pts = frame_current_pts;

    /* update delay to follow master synchronisation source */
    if (((is->av_sync_type == AV_SYNC_AUDIO_MASTER && is->audio_st) ||
         is->av_sync_type == AV_SYNC_EXTERNAL_CLOCK)) {
        /* if video is slave, we try to correct big delays by
           duplicating or deleting a frame */
        ref_clock = get_master_clock(is);
        diff = frame_current_pts - ref_clock;

        /* skip or repeat frame. We take into account the
           delay to compute the threshold. I still don't know
           if it is the best guess */
        sync_threshold = FFMAX(AV_SYNC_THRESHOLD, delay);
        if (fabs(diff) < AV_NOSYNC_THRESHOLD) {
            if (diff <= -sync_threshold)
                delay = 0;
            else if (diff >= sync_threshold)
                delay = 2 * delay;
        }
    }

    is->frame_timer += delay;
    /* compute the REAL delay (we need to do that to avoid
       long term errors */
    actual_delay = is->frame_timer - (av_gettime() / 1000000.0);
    if (actual_delay < 0.010) {
        /* XXX: should skip picture */
        actual_delay = 0.010;
    }

#if defined(DEBUG_SYNC)
    printf("video: delay=%0.3f actual_delay=%0.3f pts=%0.3f A-V=%f\n",
            delay, actual_delay, frame_current_pts, -diff);
#endif

    return actual_delay;
}

/* called to display each frame */
static void video_refresh_timer(void *opaque)
{
    VideoState *is = opaque;
    VideoPicture *vp;

    SubPicture *sp, *sp2;

    if (is->video_st) {
        if (is->pictq_size == 0) {
//            fprintf(stderr, "Internal error detected in the SDL timer\n");
        } else {
            /* dequeue the picture */
            vp = &is->pictq[is->pictq_rindex];

            /* update current video pts */
            is->video_current_pts = vp->pts;
            is->video_current_pts_drift = is->video_current_pts - av_gettime() / 1000000.0;

            if(is->subtitle_st) {
                if (is->subtitle_stream_changed) {
                    SDL_LockMutex(is->subpq_mutex);

                    while (is->subpq_size) {
                        free_subpicture(&is->subpq[is->subpq_rindex]);

                        /* update queue size and signal for next picture */
                        if (++is->subpq_rindex == SUBPICTURE_QUEUE_SIZE)
                            is->subpq_rindex = 0;

                        is->subpq_size--;
                    }
                    is->subtitle_stream_changed = 0;

                    SDL_CondSignal(is->subpq_cond);
                    SDL_UnlockMutex(is->subpq_mutex);
                } else {
                    if (is->subpq_size > 0) {
                        sp = &is->subpq[is->subpq_rindex];

                        if (is->subpq_size > 1)
                            sp2 = &is->subpq[(is->subpq_rindex + 1) % SUBPICTURE_QUEUE_SIZE];
                        else
                            sp2 = NULL;

                        if ((is->video_current_pts > (sp->pts + ((float) sp->sub.end_display_time / 1000)))
                                || (sp2 && is->video_current_pts > (sp2->pts + ((float) sp2->sub.start_display_time / 1000))))
                        {
                            free_subpicture(sp);

                            /* update queue size and signal for next picture */
                            if (++is->subpq_rindex == SUBPICTURE_QUEUE_SIZE)
                                is->subpq_rindex = 0;

                            SDL_LockMutex(is->subpq_mutex);
                            is->subpq_size--;
                            SDL_CondSignal(is->subpq_cond);
                            SDL_UnlockMutex(is->subpq_mutex);
                        }
                    }
                }
            }

            /* display picture */
            video_display(is);

            /* update queue size and signal for next picture */
            if (++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE)
                is->pictq_rindex = 0;

            SDL_LockMutex(is->pictq_mutex);
            vp->timer_id= 0;
            is->pictq_size--;
            SDL_CondSignal(is->pictq_cond);
            SDL_UnlockMutex(is->pictq_mutex);
        }
    } else if (is->audio_st) {
        /* draw the next audio frame */

        schedule_refresh(is, 40);

        /* if only audio stream, then display the audio bars (better
           than nothing, just to test the implementation */

        /* display picture */
        video_display(is);
    } else {
        schedule_refresh(is, 100);
    }
    if (show_status) {
        static int64_t last_time;
        int64_t cur_time;
        int aqsize, vqsize, sqsize;
        double av_diff;

        cur_time = av_gettime();
        if (!last_time || (cur_time - last_time) >= 30000) {
            aqsize = 0;
            vqsize = 0;
            sqsize = 0;
            if (is->audio_st)
                aqsize = is->audioq.size;
            if (is->video_st)
                vqsize = is->videoq.size;
            if (is->subtitle_st)
                sqsize = is->subtitleq.size;
            av_diff = 0;
            if (is->audio_st && is->video_st)
                av_diff = get_audio_clock(is) - get_video_clock(is);
            printf("%7.2f A-V:%7.3f aq=%5dKB vq=%5dKB sq=%5dB f=%Ld/%Ld   \r",
                   get_master_clock(is), av_diff, aqsize / 1024, vqsize / 1024, sqsize, is->faulty_dts, is->faulty_pts);
            fflush(stdout);
            last_time = cur_time;
        }
    }
}

/* allocate a picture (needs to do that in main thread to avoid
   potential locking problems */
static void alloc_picture(void *opaque)
{
    VideoState *is = opaque;
    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);
}

/**
 *
 * @param pts the dts of the pkt / pts of the frame and guessed if not known
 */
static int queue_picture(VideoState *is, AVFrame *src_frame, double pts)
{
    VideoPicture *vp;
    int dst_pix_fmt;

    /* wait until we have space to put a new picture */
    SDL_LockMutex(is->pictq_mutex);
    while (is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE &&
           !is->videoq.abort_request) {
        SDL_CondWait(is->pictq_cond, is->pictq_mutex);
    }
    SDL_UnlockMutex(is->pictq_mutex);

    if (is->videoq.abort_request)
        return -1;

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

    /* alloc or resize hardware picture buffer */
    if (!vp->bmp ||
        vp->width != is->video_st->codec->width ||
        vp->height != is->video_st->codec->height) {
        SDL_Event event;

        vp->allocated = 0;

        /* the allocation must be done in the main thread to avoid
           locking problems */
        event.type = FF_ALLOC_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);

        /* wait until the picture is allocated */
        SDL_LockMutex(is->pictq_mutex);
        while (!vp->allocated && !is->videoq.abort_request) {
            SDL_CondWait(is->pictq_cond, is->pictq_mutex);
        }
        SDL_UnlockMutex(is->pictq_mutex);

        if (is->videoq.abort_request)
            return -1;
    }

    /* if the frame is not skipped, then display it */
    if (vp->bmp) {
        AVPicture pict;

        /* get a pointer on the bitmap */
        SDL_LockYUVOverlay (vp->bmp);

        dst_pix_fmt = PIX_FMT_YUV420P;
        memset(&pict,0,sizeof(AVPicture));
        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_flags = av_get_int(sws_opts, "sws_flags", NULL);
        is->img_convert_ctx = sws_getCachedContext(is->img_convert_ctx,
            is->video_st->codec->width, is->video_st->codec->height,
            is->video_st->codec->pix_fmt,
            is->video_st->codec->width, is->video_st->codec->height,
            dst_pix_fmt, sws_flags, NULL, NULL, NULL);
        if (is->img_convert_ctx == NULL) {
            fprintf(stderr, "Cannot initialize the conversion context\n");
            exit(1);
        }
        sws_scale(is->img_convert_ctx, src_frame->data, src_frame->linesize,
                  0, is->video_st->codec->height, pict.data, pict.linesize);
        /* update the bitmap content */
        SDL_UnlockYUVOverlay(vp->bmp);

        vp->pts = pts;

        /* now we can update the picture count */
        if (++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE)
            is->pictq_windex = 0;
        SDL_LockMutex(is->pictq_mutex);
        is->pictq_size++;
        //We must schedule in a mutex as we must store the timer id before the timer dies or might end up freeing a alraedy freed id
        vp->timer_id= schedule_refresh(is, (int)(compute_frame_delay(vp->pts, is) * 1000 + 0.5));
        SDL_UnlockMutex(is->pictq_mutex);
    }
    return 0;
}

/**
 * compute the exact PTS for the picture if it is omitted in the stream
 * @param pts1 the dts of the pkt / pts of the frame
 */
static int output_picture2(VideoState *is, AVFrame *src_frame, double pts1)
{
    double frame_delay, pts;

    pts = pts1;

    if (pts != 0) {
        /* update video clock with pts, if present */
        is->video_clock = pts;
    } else {
        pts = is->video_clock;
    }
    /* update video clock for next frame */
    frame_delay = av_q2d(is->video_st->codec->time_base);
    /* for MPEG2, the frame can be repeated, so we update the
       clock accordingly */
    frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
    is->video_clock += frame_delay;

#if defined(DEBUG_SYNC) && 0
    {
        int ftype;
        if (src_frame->pict_type == FF_B_TYPE)
            ftype = 'B';
        else if (src_frame->pict_type == FF_I_TYPE)
            ftype = 'I';
        else
            ftype = 'P';
        printf("frame_type=%c clock=%0.3f pts=%0.3f\n",
               ftype, pts, pts1);
    }
#endif
    return queue_picture(is, src_frame, pts);
}

static int video_thread(void *arg)
{
    VideoState *is = arg;
    AVPacket pkt1, *pkt = &pkt1;
    int len1, got_picture, i;
    AVFrame *frame= avcodec_alloc_frame();
    double pts;

    for(;;) {
        while (is->paused && !is->videoq.abort_request) {
            SDL_Delay(10);
        }
        if (packet_queue_get(&is->videoq, pkt, 1) < 0)
            break;

        if(pkt->data == flush_pkt.data){
            avcodec_flush_buffers(is->video_st->codec);

            SDL_LockMutex(is->pictq_mutex);
            //Make sure there are no long delay timers (ideally we should just flush the que but thats harder)
            for(i=0; i<VIDEO_PICTURE_QUEUE_SIZE; i++){
                if(is->pictq[i].timer_id){
                    SDL_RemoveTimer(is->pictq[i].timer_id);
                    is->pictq[i].timer_id=0;
                    schedule_refresh(is, 1);
                }
            }
            while (is->pictq_size && !is->videoq.abort_request) {
                SDL_CondWait(is->pictq_cond, is->pictq_mutex);
            }
            SDL_UnlockMutex(is->pictq_mutex);

            is->last_dts_for_fault_detection=
            is->last_pts_for_fault_detection= INT64_MIN;
            continue;
        }

        /* NOTE: ipts is the PTS of the _first_ picture beginning in
           this packet, if any */
        is->video_st->codec->reordered_opaque= pkt->pts;
        len1 = avcodec_decode_video2(is->video_st->codec,
                                    frame, &got_picture,
                                    pkt);

        if(pkt->dts != AV_NOPTS_VALUE){
            is->faulty_dts += pkt->dts <= is->last_dts_for_fault_detection;
            is->last_dts_for_fault_detection= pkt->dts;
        }
        if(frame->reordered_opaque != AV_NOPTS_VALUE){
            is->faulty_pts += frame->reordered_opaque <= is->last_pts_for_fault_detection;
            is->last_pts_for_fault_detection= frame->reordered_opaque;
        }

        if(   (   decoder_reorder_pts==1
               || decoder_reorder_pts && is->faulty_pts<is->faulty_dts
               || pkt->dts == AV_NOPTS_VALUE)
           && frame->reordered_opaque != AV_NOPTS_VALUE)
            pts= frame->reordered_opaque;
        else if(pkt->dts != AV_NOPTS_VALUE)
            pts= pkt->dts;
        else
            pts= 0;
        pts *= av_q2d(is->video_st->time_base);

//            if (len1 < 0)
//                break;
        if (got_picture) {
            if (output_picture2(is, frame, pts) < 0)
                goto the_end;
        }
        av_free_packet(pkt);
        if (step)
            if (cur_stream)
                stream_pause(cur_stream);
    }
 the_end:
    av_free(frame);
    return 0;
}

static int subtitle_thread(void *arg)
{
    VideoState *is = arg;
    SubPicture *sp;
    AVPacket pkt1, *pkt = &pkt1;
    int len1, got_subtitle;
    double pts;
    int i, j;
    int r, g, b, y, u, v, a;

    for(;;) {
        while (is->paused && !is->subtitleq.abort_request) {
            SDL_Delay(10);
        }
        if (packet_queue_get(&is->subtitleq, pkt, 1) < 0)
            break;

        if(pkt->data == flush_pkt.data){
            avcodec_flush_buffers(is->subtitle_st->codec);
            continue;
        }
        SDL_LockMutex(is->subpq_mutex);
        while (is->subpq_size >= SUBPICTURE_QUEUE_SIZE &&
               !is->subtitleq.abort_request) {
            SDL_CondWait(is->subpq_cond, is->subpq_mutex);
        }
        SDL_UnlockMutex(is->subpq_mutex);

        if (is->subtitleq.abort_request)
            goto the_end;

        sp = &is->subpq[is->subpq_windex];

       /* NOTE: ipts is the PTS of the _first_ picture beginning in
           this packet, if any */
        pts = 0;
        if (pkt->pts != AV_NOPTS_VALUE)
            pts = av_q2d(is->subtitle_st->time_base)*pkt->pts;

        len1 = avcodec_decode_subtitle2(is->subtitle_st->codec,
                                    &sp->sub, &got_subtitle,
                                    pkt);
//            if (len1 < 0)
//                break;
        if (got_subtitle && sp->sub.format == 0) {
            sp->pts = pts;

            for (i = 0; i < sp->sub.num_rects; i++)
            {
                for (j = 0; j < sp->sub.rects[i]->nb_colors; j++)
                {
                    RGBA_IN(r, g, b, a, (uint32_t*)sp->sub.rects[i]->pict.data[1] + j);
                    y = RGB_TO_Y_CCIR(r, g, b);
                    u = RGB_TO_U_CCIR(r, g, b, 0);
                    v = RGB_TO_V_CCIR(r, g, b, 0);
                    YUVA_OUT((uint32_t*)sp->sub.rects[i]->pict.data[1] + j, y, u, v, a);
                }
            }

            /* now we can update the picture count */
            if (++is->subpq_windex == SUBPICTURE_QUEUE_SIZE)
                is->subpq_windex = 0;
            SDL_LockMutex(is->subpq_mutex);
            is->subpq_size++;
            SDL_UnlockMutex(is->subpq_mutex);
        }
        av_free_packet(pkt);
//        if (step)
//            if (cur_stream)
//                stream_pause(cur_stream);
    }
 the_end:
    return 0;
}

/* copy samples for viewing in editor window */
static void update_sample_display(VideoState *is, short *samples, int samples_size)
{
    int size, len, channels;

    channels = is->audio_st->codec->channels;

    size = samples_size / sizeof(short);
    while (size > 0) {
        len = SAMPLE_ARRAY_SIZE - is->sample_array_index;
        if (len > size)
            len = size;
        memcpy(is->sample_array + is->sample_array_index, samples, len * sizeof(short));
        samples += len;
        is->sample_array_index += len;
        if (is->sample_array_index >= SAMPLE_ARRAY_SIZE)
            is->sample_array_index = 0;
        size -= len;
    }
}

/* return the new audio buffer size (samples can be added or deleted
   to get better sync if video or external master clock) */
static int synchronize_audio(VideoState *is, short *samples,
                             int samples_size1, double pts)
{
    int n, samples_size;
    double ref_clock;

    n = 2 * is->audio_st->codec->channels;
    samples_size = samples_size1;

    /* if not master, then we try to remove or add samples to correct the clock */
    if (((is->av_sync_type == AV_SYNC_VIDEO_MASTER && is->video_st) ||
         is->av_sync_type == AV_SYNC_EXTERNAL_CLOCK)) {
        double diff, avg_diff;
        int wanted_size, min_size, max_size, nb_samples;

        ref_clock = get_master_clock(is);
        diff = get_audio_clock(is) - ref_clock;

        if (diff < AV_NOSYNC_THRESHOLD) {
            is->audio_diff_cum = diff + is->audio_diff_avg_coef * is->audio_diff_cum;
            if (is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) {
                /* not enough measures to have a correct estimate */
                is->audio_diff_avg_count++;
            } else {
                /* estimate the A-V difference */
                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 *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) {
        if (enc->channels > 0) {
            enc->request_channels = FFMIN(2, enc->channels);
        } else {
            enc->request_channels = 2;
        }
    }

    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_recognition= error_recognition;
    enc->error_concealment= error_concealment;
    avcodec_thread_init(enc, thread_count);

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

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

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

    ic->streams[stream_index]->discard = AVDISCARD_DEFAULT;
    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);
        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);
        if (is->reformat_ctx)
            av_audio_convert_free(is->reformat_ctx);
        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;
    }

    ic->streams[stream_index]->discard = AVDISCARD_ALL;
    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;
    }
}

/* 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, subtitle_index;
    AVPacket pkt1, *pkt = &pkt1;
    AVFormatParameters params, *ap = &params;
    int eof=0;

    ic = avformat_alloc_context();

    video_index = -1;
    audio_index = -1;
    subtitle_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->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 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++) {
        AVCodecContext *enc = ic->streams[i]->codec;
        ic->streams[i]->discard = AVDISCARD_ALL;
        switch(enc->codec_type) {
        case CODEC_TYPE_AUDIO:
            if (wanted_audio_stream-- >= 0 && !audio_disable)
                audio_index = i;
            break;
        case CODEC_TYPE_VIDEO:
            if (wanted_video_stream-- >= 0 && !video_disable)
                video_index = i;
            break;
        case CODEC_TYPE_SUBTITLE:
            if (wanted_subtitle_stream-- >= 0 && !video_disable)
                subtitle_index = i;
            break;
        default:
            break;
        }
    }
    if (show_status) {
        dump_format(ic, 0, is->filename, 0);
    }