avplay.c

    } else if (is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
        if (is->audio_st)
            val = get_audio_clock(is);
        else
            val = get_video_clock(is);
    } else {
        val = get_external_clock(is);
    }
    return val;
}

/* seek in the stream */
static void stream_seek(VideoState *is, int64_t pos, int64_t rel, int seek_by_bytes)
{
    if (!is->seek_req) {
        is->seek_pos = pos;
        is->seek_rel = rel;
        is->seek_flags &= ~AVSEEK_FLAG_BYTE;
        if (seek_by_bytes)
            is->seek_flags |= AVSEEK_FLAG_BYTE;
        is->seek_req = 1;
    }
}

/* pause or resume the video */
static void stream_pause(VideoState *is)
{
    if (is->paused) {
        is->frame_timer += av_gettime() / 1000000.0 + is->video_current_pts_drift - is->video_current_pts;
        if (is->read_pause_return != AVERROR(ENOSYS)) {
            is->video_current_pts = is->video_current_pts_drift + av_gettime() / 1000000.0;
        }
        is->video_current_pts_drift = is->video_current_pts - av_gettime() / 1000000.0;
    }
    is->paused = !is->paused;
}

static double compute_target_time(double frame_current_pts, VideoState *is)
{
    double delay, sync_threshold, 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 */
        diff = get_video_clock(is) - get_master_clock(is);

        /* 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;

    av_dlog(NULL, "video: delay=%0.3f pts=%0.3f A-V=%f\n",
            delay, frame_current_pts, -diff);

    return is->frame_timer;
}

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

    SubPicture *sp, *sp2;

    if (is->video_st) {
retry:
        if (is->pictq_size == 0) {
            // nothing to do, no picture to display in the que
        } else {
            double time = av_gettime() / 1000000.0;
            double next_target;
            /* dequeue the picture */
            vp = &is->pictq[is->pictq_rindex];

            if (time < vp->target_clock)
                return;
            /* update current video pts */
            is->video_current_pts = vp->pts;
            is->video_current_pts_drift = is->video_current_pts - time;
            is->video_current_pos = vp->pos;
            if (is->pictq_size > 1) {
                VideoPicture *nextvp = &is->pictq[(is->pictq_rindex + 1) % VIDEO_PICTURE_QUEUE_SIZE];
                assert(nextvp->target_clock >= vp->target_clock);
                next_target= nextvp->target_clock;
            } else {
                next_target = vp->target_clock + is->video_clock - vp->pts; // FIXME pass durations cleanly
            }
            if (framedrop && time > next_target) {
                is->skip_frames *= 1.0 + FRAME_SKIP_FACTOR;
                if (is->pictq_size > 1 || time > next_target + 0.5) {
                    /* 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);
                    is->pictq_size--;
                    SDL_CondSignal(is->pictq_cond);
                    SDL_UnlockMutex(is->pictq_mutex);
                    goto retry;
                }
            }

            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 */
            if (!display_disable)
                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);
            is->pictq_size--;
            SDL_CondSignal(is->pictq_cond);
            SDL_UnlockMutex(is->pictq_mutex);
        }
    } else if (is->audio_st) {
        /* draw the next audio frame */

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

        /* display picture */
        if (!display_disable)
            video_display(is);
    }
    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 s:%3.1f aq=%5dKB vq=%5dKB sq=%5dB f=%"PRId64"/%"PRId64"   \r",
                   get_master_clock(is), av_diff, FFMAX(is->skip_frames - 1, 0), aqsize / 1024,
                   vqsize / 1024, sqsize, is->pts_ctx.num_faulty_dts, is->pts_ctx.num_faulty_pts);
            fflush(stdout);
            last_time = cur_time;
        }
    }
}

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
        avfilter_unref_bufferp(&vp->picref);
#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 do_exit(void)
{
    if (cur_stream) {
        stream_close(cur_stream);
        cur_stream = NULL;
    }
    uninit_opts();
#if CONFIG_AVFILTER
    avfilter_uninit();
#endif
    avformat_network_deinit();
    if (show_status)
        printf("\n");
    SDL_Quit();
    av_log(NULL, AV_LOG_QUIET, "");
    exit(0);
}

/* 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);

#if CONFIG_AVFILTER
    avfilter_unref_bufferp(&vp->picref);

    vp->width   = is->out_video_filter->inputs[0]->w;
    vp->height  = is->out_video_filter->inputs[0]->h;
    vp->pix_fmt = is->out_video_filter->inputs[0]->format;
#else
    vp->width   = is->video_st->codec->width;
    vp->height  = is->video_st->codec->height;
    vp->pix_fmt = is->video_st->codec->pix_fmt;
#endif

    vp->bmp = SDL_CreateYUVOverlay(vp->width, vp->height,
                                   SDL_YV12_OVERLAY,
                                   screen);
    if (!vp->bmp || vp->bmp->pitches[0] < vp->width) {
        /* SDL allocates a buffer smaller than requested if the video
         * overlay hardware is unable to support the requested size. */
        fprintf(stderr, "Error: the video system does not support an image\n"
                        "size of %dx%d pixels. Try using -vf \"scale=w:h\"\n"
                        "to reduce the image size.\n", vp->width, vp->height );
        do_exit();
    }

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

/* The 'pts' parameter is the dts of the packet / pts of the frame and
 * guessed if not known. */
static int queue_picture(VideoState *is, AVFrame *src_frame, double pts, int64_t pos)
{
    VideoPicture *vp;
#if CONFIG_AVFILTER
    AVPicture pict_src;
#else
    int dst_pix_fmt = AV_PIX_FMT_YUV420P;
#endif
    /* wait until we have space to put a new picture */
    SDL_LockMutex(is->pictq_mutex);

    if (is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE && !is->refresh)
        is->skip_frames = FFMAX(1.0 - FRAME_SKIP_FACTOR, is->skip_frames * (1.0 - FRAME_SKIP_FACTOR));

    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->reallocate ||
#if CONFIG_AVFILTER
        vp->width  != is->out_video_filter->inputs[0]->w ||
        vp->height != is->out_video_filter->inputs[0]->h) {
#else
        vp->width != is->video_st->codec->width ||
        vp->height != is->video_st->codec->height) {
#endif
        SDL_Event event;

        vp->allocated  = 0;
        vp->reallocate = 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 = { { 0 } };
#if CONFIG_AVFILTER
        avfilter_unref_bufferp(&vp->picref);
        vp->picref = src_frame->opaque;
#endif

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

        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];

#if CONFIG_AVFILTER
        pict_src.data[0] = src_frame->data[0];
        pict_src.data[1] = src_frame->data[1];
        pict_src.data[2] = src_frame->data[2];

        pict_src.linesize[0] = src_frame->linesize[0];
        pict_src.linesize[1] = src_frame->linesize[1];
        pict_src.linesize[2] = src_frame->linesize[2];

        // FIXME use direct rendering
        av_picture_copy(&pict, &pict_src,
                        vp->pix_fmt, vp->width, vp->height);
#else
        sws_flags = av_get_int(sws_opts, "sws_flags", NULL);
        is->img_convert_ctx = sws_getCachedContext(is->img_convert_ctx,
            vp->width, vp->height, vp->pix_fmt, vp->width, vp->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, vp->height, pict.data, pict.linesize);
#endif
        /* update the bitmap content */
        SDL_UnlockYUVOverlay(vp->bmp);

        vp->pts = pts;
        vp->pos = pos;

        /* now we can update the picture count */
        if (++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE)
            is->pictq_windex = 0;
        SDL_LockMutex(is->pictq_mutex);
        vp->target_clock = compute_target_time(vp->pts, is);

        is->pictq_size++;
        SDL_UnlockMutex(is->pictq_mutex);
    }
    return 0;
}

/* Compute the exact PTS for the picture if it is omitted in the stream.
 * The 'pts1' parameter is the dts of the packet / pts of the frame. */
static int output_picture2(VideoState *is, AVFrame *src_frame, double pts1, int64_t pos)
{
    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;

    return queue_picture(is, src_frame, pts, pos);
}

static int get_video_frame(VideoState *is, AVFrame *frame, int64_t *pts, AVPacket *pkt)
{
    int got_picture, i;

    if (packet_queue_get(&is->videoq, pkt, 1) < 0)
        return -1;

    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++) {
            is->pictq[i].target_clock= 0;
        }
        while (is->pictq_size && !is->videoq.abort_request) {
            SDL_CondWait(is->pictq_cond, is->pictq_mutex);
        }
        is->video_current_pos = -1;
        SDL_UnlockMutex(is->pictq_mutex);

        init_pts_correction(&is->pts_ctx);
        is->frame_last_pts = AV_NOPTS_VALUE;
        is->frame_last_delay = 0;
        is->frame_timer = (double)av_gettime() / 1000000.0;
        is->skip_frames = 1;
        is->skip_frames_index = 0;
        return 0;
    }

    avcodec_decode_video2(is->video_st->codec, frame, &got_picture, pkt);

    if (got_picture) {
        if (decoder_reorder_pts == -1) {
            *pts = guess_correct_pts(&is->pts_ctx, frame->pkt_pts, frame->pkt_dts);
        } else if (decoder_reorder_pts) {
            *pts = frame->pkt_pts;
        } else {
            *pts = frame->pkt_dts;
        }

        if (*pts == AV_NOPTS_VALUE) {
            *pts = 0;
        }

        is->skip_frames_index += 1;
        if (is->skip_frames_index >= is->skip_frames) {
            is->skip_frames_index -= FFMAX(is->skip_frames, 1.0);
            return 1;
        }

    }
    return 0;
}

#if CONFIG_AVFILTER
static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const char *vfilters)
{
    char sws_flags_str[128];
    char buffersrc_args[256];
    int ret;
    AVFilterContext *filt_src = NULL, *filt_out = NULL, *filt_format;
    AVCodecContext *codec = is->video_st->codec;

    snprintf(sws_flags_str, sizeof(sws_flags_str), "flags=%d", sws_flags);
    graph->scale_sws_opts = av_strdup(sws_flags_str);

    snprintf(buffersrc_args, sizeof(buffersrc_args), "%d:%d:%d:%d:%d:%d:%d",
             codec->width, codec->height, codec->pix_fmt,
             is->video_st->time_base.num, is->video_st->time_base.den,
             codec->sample_aspect_ratio.num, codec->sample_aspect_ratio.den);


    if ((ret = avfilter_graph_create_filter(&filt_src,
                                            avfilter_get_by_name("buffer"),
                                            "src", buffersrc_args, NULL,
                                            graph)) < 0)
        return ret;
    if ((ret = avfilter_graph_create_filter(&filt_out,
                                            avfilter_get_by_name("buffersink"),
                                            "out", NULL, NULL, graph)) < 0)
        return ret;

    if ((ret = avfilter_graph_create_filter(&filt_format,
                                            avfilter_get_by_name("format"),
                                            "format", "yuv420p", NULL, graph)) < 0)
        return ret;
    if ((ret = avfilter_link(filt_format, 0, filt_out, 0)) < 0)
        return ret;


    if (vfilters) {
        AVFilterInOut *outputs = avfilter_inout_alloc();
        AVFilterInOut *inputs  = avfilter_inout_alloc();

        outputs->name    = av_strdup("in");
        outputs->filter_ctx = filt_src;
        outputs->pad_idx = 0;
        outputs->next    = NULL;

        inputs->name    = av_strdup("out");
        inputs->filter_ctx = filt_format;
        inputs->pad_idx = 0;
        inputs->next    = NULL;

        if ((ret = avfilter_graph_parse(graph, vfilters, inputs, outputs, NULL)) < 0)
            return ret;
    } else {
        if ((ret = avfilter_link(filt_src, 0, filt_format, 0)) < 0)
            return ret;
    }

    if ((ret = avfilter_graph_config(graph, NULL)) < 0)
        return ret;

    is->in_video_filter  = filt_src;
    is->out_video_filter = filt_out;

    if (codec->codec->capabilities & CODEC_CAP_DR1) {
        is->use_dr1 = 1;
        codec->get_buffer     = codec_get_buffer;
        codec->release_buffer = codec_release_buffer;
        codec->opaque         = &is->buffer_pool;
    }

    return ret;
}

#endif  /* CONFIG_AVFILTER */

static int video_thread(void *arg)
{
    AVPacket pkt = { 0 };
    VideoState *is = arg;
    AVFrame *frame = avcodec_alloc_frame();
    int64_t pts_int;
    double pts;
    int ret;

#if CONFIG_AVFILTER
    AVFilterGraph *graph = avfilter_graph_alloc();
    AVFilterContext *filt_out = NULL, *filt_in = NULL;
    int64_t pos;
    int last_w = is->video_st->codec->width;
    int last_h = is->video_st->codec->height;

    if ((ret = configure_video_filters(graph, is, vfilters)) < 0)
        goto the_end;
    filt_in  = is->in_video_filter;
    filt_out = is->out_video_filter;
#endif

    for (;;) {
#if CONFIG_AVFILTER
        AVFilterBufferRef *picref;
        AVRational tb;
#endif
        while (is->paused && !is->videoq.abort_request)
            SDL_Delay(10);

        av_free_packet(&pkt);

        ret = get_video_frame(is, frame, &pts_int, &pkt);
        if (ret < 0)
            goto the_end;

        if (!ret)
            continue;

#if CONFIG_AVFILTER
        if (   last_w != is->video_st->codec->width
            || last_h != is->video_st->codec->height) {
            av_dlog(NULL, "Changing size %dx%d -> %dx%d\n", last_w, last_h,
                    is->video_st->codec->width, is->video_st->codec->height);
            avfilter_graph_free(&graph);
            graph = avfilter_graph_alloc();
            if ((ret = configure_video_filters(graph, is, vfilters)) < 0)
                goto the_end;
            filt_in  = is->in_video_filter;
            filt_out = is->out_video_filter;
            last_w = is->video_st->codec->width;
            last_h = is->video_st->codec->height;
        }

        frame->pts = pts_int;
        if (is->use_dr1) {
            FrameBuffer      *buf = frame->opaque;
            AVFilterBufferRef *fb = avfilter_get_video_buffer_ref_from_arrays(
                                        frame->data, frame->linesize,
                                        AV_PERM_READ | AV_PERM_PRESERVE,
                                        frame->width, frame->height,
                                        frame->format);

            avfilter_copy_frame_props(fb, frame);
            fb->buf->priv           = buf;
            fb->buf->free           = filter_release_buffer;

            buf->refcount++;
            av_buffersrc_buffer(filt_in, fb);

        } else
            av_buffersrc_write_frame(filt_in, frame);

        while (ret >= 0) {
            ret = av_buffersink_read(filt_out, &picref);
            if (ret < 0) {
                ret = 0;
                break;
            }

            avfilter_copy_buf_props(frame, picref);

            pts_int = picref->pts;
            tb      = filt_out->inputs[0]->time_base;
            pos     = picref->pos;
            frame->opaque = picref;

            if (av_cmp_q(tb, is->video_st->time_base)) {
                av_unused int64_t pts1 = pts_int;
                pts_int = av_rescale_q(pts_int, tb, is->video_st->time_base);
                av_dlog(NULL, "video_thread(): "
                        "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
                        tb.num, tb.den, pts1,
                        is->video_st->time_base.num, is->video_st->time_base.den, pts_int);
            }
            pts = pts_int * av_q2d(is->video_st->time_base);
            ret = output_picture2(is, frame, pts, pos);
        }
#else
        pts = pts_int * av_q2d(is->video_st->time_base);
        ret = output_picture2(is, frame, pts,  pkt.pos);
#endif

        if (ret < 0)
            goto the_end;

        if (step)
            if (cur_stream)
                stream_pause(cur_stream);
    }
 the_end:
#if CONFIG_AVFILTER
    av_freep(&vfilters);
    avfilter_graph_free(&graph);
#endif
    av_free_packet(&pkt);
    avcodec_free_frame(&frame);
    return 0;
}

static int subtitle_thread(void *arg)
{
    VideoState *is = arg;
    SubPicture *sp;
    AVPacket pkt1, *pkt = &pkt1;
    int 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)
            return 0;

        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;

        avcodec_decode_subtitle2(is->subtitle_st->codec, &sp->sub,
                                 &got_subtitle, pkt);

        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);
    }
    return 0;
}

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

    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 = is->sdl_channels * av_get_bytes_per_sample(is->sdl_sample_fmt);
    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->sdl_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;
                    }
                }
                av_dlog(NULL, "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);
            }
        } 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, got_frame;
    double pts;
    int new_packet = 0;
    int flush_complete = 0;

    for (;;) {
        /* NOTE: the audio packet can contain several frames */
        while (pkt_temp->size > 0 || (!pkt_temp->data && new_packet)) {
            int resample_changed, audio_resample;

            if (!is->frame) {
                if (!(is->frame = avcodec_alloc_frame()))
                    return AVERROR(ENOMEM);
            } else
                avcodec_get_frame_defaults(is->frame);

            if (flush_complete)
                break;
            new_packet = 0;
            len1 = avcodec_decode_audio4(dec, is->frame, &got_frame, 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 (!got_frame) {
                /* stop sending empty packets if the decoder is finished */
                if (!pkt_temp->data && dec->codec->capabilities & CODEC_CAP_DELAY)
                    flush_complete = 1;
                continue;
            }
            data_size = av_samples_get_buffer_size(NULL, dec->channels,
                                                   is->frame->nb_samples,
                                                   is->frame->format, 1);

            audio_resample = is->frame->format         != is->sdl_sample_fmt     ||
                             is->frame->channel_layout != is->sdl_channel_layout ||
                             is->frame->sample_rate    != is->sdl_sample_rate;

            resample_changed = is->frame->format         != is->resample_sample_fmt     ||
                               is->frame->channel_layout != is->resample_channel_layout ||
                               is->frame->sample_rate    != is->resample_sample_rate;

            if ((!is->avr && audio_resample) || resample_changed) {
                int ret;
                if (is->avr)
                    avresample_close(is->avr);
                else if (audio_resample) {
                    is->avr = avresample_alloc_context();
                    if (!is->avr) {
                        fprintf(stderr, "error allocating AVAudioResampleContext\n");
                        break;
                    }
                }
                if (audio_resample) {
                    av_opt_set_int(is->avr, "in_channel_layout",  is->frame->channel_layout, 0);
                    av_opt_set_int(is->avr, "in_sample_fmt",      is->frame->format,         0);
                    av_opt_set_int(is->avr, "in_sample_rate",     is->frame->sample_rate,    0);
                    av_opt_set_int(is->avr, "out_channel_layout", is->sdl_channel_layout,    0);
                    av_opt_set_int(is->avr, "out_sample_fmt",     is->sdl_sample_fmt,        0);
                    av_opt_set_int(is->avr, "out_sample_rate",    is->sdl_sample_rate,       0);

                    if ((ret = avresample_open(is->avr)) < 0) {
                        fprintf(stderr, "error initializing libavresample\n");
                        break;
                    }
                }
                is->resample_sample_fmt     = is->frame->format;
                is->resample_channel_layout = is->frame->channel_layout;
                is->resample_sample_rate    = is->frame->sample_rate;
            }

            if (audio_resample) {
                void *tmp_out;
                int out_samples, out_size, out_linesize;
                int osize      = av_get_bytes_per_sample(is->sdl_sample_fmt);
                int nb_samples = is->frame->nb_samples;

                out_size = av_samples_get_buffer_size(&out_linesize,
                                                      is->sdl_channels,
                                                      nb_samples,
                                                      is->sdl_sample_fmt, 0);
                tmp_out = av_realloc(is->audio_buf1, out_size);
                if (!tmp_out)
                    return AVERROR(ENOMEM);
                is->audio_buf1 = tmp_out;

                out_samples = avresample_convert(is->avr,
                                                 &is->audio_buf1,
                                                 out_linesize, nb_samples,
                                                 is->frame->data,
                                                 is->frame->linesize[0],
                                                 is->frame->nb_samples);
                if (out_samples < 0) {
                    fprintf(stderr, "avresample_convert() failed\n");
                    break;
                }
                is->audio_buf = is->audio_buf1;
                data_size = out_samples * osize * is->sdl_channels;
            } else {
                is->audio_buf = is->frame->data[0];
            }

            /* if no pts, then compute it */
            pts = is->audio_clock;
            *pts_ptr = pts;
            n = is->sdl_channels * av_get_bytes_per_sample(is->sdl_sample_fmt);
            is->audio_clock += (double)data_size /
                (double)(n * is->sdl_sample_rate);
#ifdef DEBUG
            {
                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);