ffplay.c

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->read_tid, NULL);
    packet_queue_destroy(&is->videoq);
    packet_queue_destroy(&is->audioq);
    packet_queue_destroy(&is->subtitleq);

    /* free all pictures */
    for (i = 0; i < VIDEO_PICTURE_QUEUE_SIZE; i++) {
        vp = &is->pictq[i];
        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);
    SDL_DestroyCond(is->continue_read_thread);
#if !CONFIG_AVFILTER
    sws_freeContext(is->img_convert_ctx);
#endif
    av_free(is);
}

static void do_exit(VideoState *is)
{
    if (is) {
        stream_close(is);
    }
    av_lockmgr_register(NULL);
    uninit_opts();
#if CONFIG_AVFILTER
    av_freep(&vfilters);
#endif
    avformat_network_deinit();
    if (show_status)
        printf("\n");
    SDL_Quit();
    av_log(NULL, AV_LOG_QUIET, "%s", "");
    exit(0);
}

static void sigterm_handler(int sig)
{
    exit(123);
}

static int video_open(VideoState *is, int force_set_video_mode, VideoPicture *vp)
{
    int flags = SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_HWACCEL;
    int w,h;
    SDL_Rect rect;

    if (is_full_screen) flags |= SDL_FULLSCREEN;
    else                flags |= SDL_RESIZABLE;

    if (vp && vp->width) {
        calculate_display_rect(&rect, 0, 0, INT_MAX, vp->height, vp);
        default_width  = rect.w;
        default_height = rect.h;
    }

    if (is_full_screen && fs_screen_width) {
        w = fs_screen_width;
        h = fs_screen_height;
    } else if (!is_full_screen && screen_width) {
        w = screen_width;
        h = screen_height;
    } else {
        w = default_width;
        h = default_height;
    }
    if (screen && is->width == screen->w && screen->w == w
       && is->height== screen->h && screen->h == h && !force_set_video_mode)
        return 0;
    screen = SDL_SetVideoMode(w, h, 0, flags);
    if (!screen) {
        fprintf(stderr, "SDL: could not set video mode - exiting\n");
        do_exit(is);
    }
    if (!window_title)
        window_title = input_filename;
    SDL_WM_SetCaption(window_title, window_title);

    is->width  = screen->w;
    is->height = screen->h;

    return 0;
}

/* display the current picture, if any */
static void video_display(VideoState *is)
{
    if (!screen)
        video_open(is, 0, NULL);
    if (is->audio_st && is->show_mode != SHOW_MODE_VIDEO)
        video_audio_display(is);
    else if (is->video_st)
        video_image_display(is);
}

static double get_clock(Clock *c)
{
    if (*c->queue_serial != c->serial)
        return NAN;
    if (c->paused) {
        return c->pts;
    } else {
        double time = av_gettime() / 1000000.0;
        return c->pts_drift + time - (time - c->last_updated) * (1.0 - c->speed);
    }
}

static void set_clock_at(Clock *c, double pts, int serial, double time)
{
    c->pts = pts;
    c->last_updated = time;
    c->pts_drift = c->pts - time;
    c->serial = serial;
}

static void set_clock(Clock *c, double pts, int serial)
{
    double time = av_gettime() / 1000000.0;
    set_clock_at(c, pts, serial, time);
}

static void set_clock_speed(Clock *c, double speed)
{
    set_clock(c, get_clock(c), c->serial);
    c->speed = speed;
}

static void init_clock(Clock *c, int *queue_serial)
{
    c->speed = 1.0;
    c->paused = 0;
    c->queue_serial = queue_serial;
    set_clock(c, NAN, -1);
}

static void sync_clock_to_slave(Clock *c, Clock *slave)
{
    double clock = get_clock(c);
    double slave_clock = get_clock(slave);
    if (!isnan(slave_clock) && (isnan(clock) || fabs(clock - slave_clock) > AV_NOSYNC_THRESHOLD))
        set_clock(c, slave_clock, slave->serial);
}

static int get_master_sync_type(VideoState *is) {
    if (is->av_sync_type == AV_SYNC_VIDEO_MASTER) {
        if (is->video_st)
            return AV_SYNC_VIDEO_MASTER;
        else
            return AV_SYNC_AUDIO_MASTER;
    } else if (is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
        if (is->audio_st)
            return AV_SYNC_AUDIO_MASTER;
        else
            return AV_SYNC_EXTERNAL_CLOCK;
    } else {
        return AV_SYNC_EXTERNAL_CLOCK;
    }
}

/* get the current master clock value */
static double get_master_clock(VideoState *is)
{
    double val;

    switch (get_master_sync_type(is)) {
        case AV_SYNC_VIDEO_MASTER:
            val = get_clock(&is->vidclk);
            break;
        case AV_SYNC_AUDIO_MASTER:
            val = get_clock(&is->audclk);
            break;
        default:
            val = get_clock(&is->extclk);
            break;
    }
    return val;
}

static void check_external_clock_speed(VideoState *is) {
   if (is->video_stream >= 0 && is->videoq.nb_packets <= MIN_FRAMES / 2 ||
       is->audio_stream >= 0 && is->audioq.nb_packets <= MIN_FRAMES / 2) {
       set_clock_speed(&is->extclk, FFMAX(EXTERNAL_CLOCK_SPEED_MIN, is->extclk.speed - EXTERNAL_CLOCK_SPEED_STEP));
   } else if ((is->video_stream < 0 || is->videoq.nb_packets > MIN_FRAMES * 2) &&
              (is->audio_stream < 0 || is->audioq.nb_packets > MIN_FRAMES * 2)) {
       set_clock_speed(&is->extclk, FFMIN(EXTERNAL_CLOCK_SPEED_MAX, is->extclk.speed + EXTERNAL_CLOCK_SPEED_STEP));
   } else {
       double speed = is->extclk.speed;
       if (speed != 1.0)
           set_clock_speed(&is->extclk, speed + EXTERNAL_CLOCK_SPEED_STEP * (1.0 - speed) / fabs(1.0 - speed));
   }
}

/* 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;
        SDL_CondSignal(is->continue_read_thread);
    }
}

/* pause or resume the video */
static void stream_toggle_pause(VideoState *is)
{
    if (is->paused) {
        is->frame_timer += av_gettime() / 1000000.0 + is->vidclk.pts_drift - is->vidclk.pts;
        if (is->read_pause_return != AVERROR(ENOSYS)) {
            is->vidclk.paused = 0;
        }
        set_clock(&is->vidclk, get_clock(&is->vidclk), is->vidclk.serial);
    }
    set_clock(&is->extclk, get_clock(&is->extclk), is->extclk.serial);
    is->paused = is->audclk.paused = is->vidclk.paused = is->extclk.paused = !is->paused;
}

static void toggle_pause(VideoState *is)
{
    stream_toggle_pause(is);
    is->step = 0;
}

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

static double compute_target_delay(double delay, VideoState *is)
{
    double sync_threshold, diff;

    /* update delay to follow master synchronisation source */
    if (get_master_sync_type(is) != AV_SYNC_VIDEO_MASTER) {
        /* if video is slave, we try to correct big delays by
           duplicating or deleting a frame */
        diff = get_clock(&is->vidclk) - 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 (!isnan(diff) && fabs(diff) < AV_NOSYNC_THRESHOLD) {
            if (diff <= -sync_threshold)
                delay = 0;
            else if (diff >= sync_threshold)
                delay = 2 * delay;
        }
    }

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

    return delay;
}

static void pictq_next_picture(VideoState *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);
}

static int pictq_prev_picture(VideoState *is) {
    VideoPicture *prevvp;
    int ret = 0;
    /* update queue size and signal for the previous picture */
    prevvp = &is->pictq[(is->pictq_rindex + VIDEO_PICTURE_QUEUE_SIZE - 1) % VIDEO_PICTURE_QUEUE_SIZE];
    if (prevvp->allocated && prevvp->serial == is->videoq.serial) {
        SDL_LockMutex(is->pictq_mutex);
        if (is->pictq_size < VIDEO_PICTURE_QUEUE_SIZE) {
            if (--is->pictq_rindex == -1)
                is->pictq_rindex = VIDEO_PICTURE_QUEUE_SIZE - 1;
            is->pictq_size++;
            ret = 1;
        }
        SDL_CondSignal(is->pictq_cond);
        SDL_UnlockMutex(is->pictq_mutex);
    }
    return ret;
}

static void update_video_pts(VideoState *is, double pts, int64_t pos, int serial) {
    /* update current video pts */
    set_clock(&is->vidclk, pts, serial);
    sync_clock_to_slave(&is->extclk, &is->vidclk);
    is->video_current_pos = pos;
    is->frame_last_pts = pts;
}

/* called to display each frame */
static void video_refresh(void *opaque, double *remaining_time)
{
    VideoState *is = opaque;
    VideoPicture *vp;
    double time;

    SubPicture *sp, *sp2;

    if (!is->paused && get_master_sync_type(is) == AV_SYNC_EXTERNAL_CLOCK && is->realtime)
        check_external_clock_speed(is);

    if (!display_disable && is->show_mode != SHOW_MODE_VIDEO && is->audio_st) {
        time = av_gettime() / 1000000.0;
        if (is->force_refresh || is->last_vis_time + rdftspeed < time) {
            video_display(is);
            is->last_vis_time = time;
        }
        *remaining_time = FFMIN(*remaining_time, is->last_vis_time + rdftspeed - time);
    }

    if (is->video_st) {
        int redisplay = 0;
        if (is->force_refresh)
            redisplay = pictq_prev_picture(is);
retry:
        if (is->pictq_size == 0) {
            SDL_LockMutex(is->pictq_mutex);
            if (is->frame_last_dropped_pts != AV_NOPTS_VALUE && is->frame_last_dropped_pts > is->frame_last_pts) {
                update_video_pts(is, is->frame_last_dropped_pts, is->frame_last_dropped_pos, is->frame_last_dropped_serial);
                is->frame_last_dropped_pts = AV_NOPTS_VALUE;
            }
            SDL_UnlockMutex(is->pictq_mutex);
            // nothing to do, no picture to display in the queue
        } else {
            double last_duration, duration, delay;
            /* dequeue the picture */
            vp = &is->pictq[is->pictq_rindex];

            if (vp->serial != is->videoq.serial) {
                pictq_next_picture(is);
                redisplay = 0;
                goto retry;
            }

            if (is->paused)
                goto display;

            /* compute nominal last_duration */
            last_duration = vp->pts - is->frame_last_pts;
            if (!isnan(last_duration) && last_duration > 0 && last_duration < is->max_frame_duration) {
                /* if duration of the last frame was sane, update last_duration in video state */
                is->frame_last_duration = last_duration;
            }
            delay = compute_target_delay(is->frame_last_duration, is);

            time= av_gettime()/1000000.0;
            if (time < is->frame_timer + delay && !redisplay) {
                *remaining_time = FFMIN(is->frame_timer + delay - time, *remaining_time);
                return;
            }

            if (delay > 0)
                is->frame_timer += delay * FFMAX(1, floor((time-is->frame_timer) / delay));

            SDL_LockMutex(is->pictq_mutex);
            if (!isnan(vp->pts))
                update_video_pts(is, vp->pts, vp->pos, vp->serial);
            SDL_UnlockMutex(is->pictq_mutex);

            if (is->pictq_size > 1) {
                VideoPicture *nextvp = &is->pictq[(is->pictq_rindex + 1) % VIDEO_PICTURE_QUEUE_SIZE];
                duration = nextvp->pts - vp->pts;
                if(!is->step && (redisplay || framedrop>0 || (framedrop && get_master_sync_type(is) != AV_SYNC_VIDEO_MASTER)) && time > is->frame_timer + duration){
                    if (!redisplay)
                        is->frame_drops_late++;
                    pictq_next_picture(is);
                    redisplay = 0;
                    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:
            /* display picture */
            if (!display_disable && is->show_mode == SHOW_MODE_VIDEO)
                video_display(is);

            pictq_next_picture(is);

            if (is->step && !is->paused)
                stream_toggle_pause(is);
        }
    }
    is->force_refresh = 0;
    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_clock(&is->audclk) - get_clock(&is->vidclk);
            else if (is->video_st)
                av_diff = get_master_clock(is) - get_clock(&is->vidclk);
            else if (is->audio_st)
                av_diff = get_master_clock(is) - get_clock(&is->audclk);
            printf("%7.2f %s:%7.3f fd=%4d aq=%5dKB vq=%5dKB sq=%5dB f=%"PRId64"/%"PRId64"   \r",
                   get_master_clock(is),
                   (is->audio_st && is->video_st) ? "A-V" : (is->video_st ? "M-V" : (is->audio_st ? "M-A" : "   ")),
                   av_diff,
                   is->frame_drops_early + is->frame_drops_late,
                   aqsize / 1024,
                   vqsize / 1024,
                   sqsize,
                   is->video_st ? is->video_st->codec->pts_correction_num_faulty_dts : 0,
                   is->video_st ? is->video_st->codec->pts_correction_num_faulty_pts : 0);
            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(VideoState *is)
{
    VideoPicture *vp;

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

    if (vp->bmp)
        SDL_FreeYUVOverlay(vp->bmp);

    video_open(is, 0, vp);

    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 -lowres or -vf \"scale=w:h\"\n"
                        "to reduce the image size.\n", vp->width, vp->height );
        do_exit(is);
    }

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

static void duplicate_right_border_pixels(SDL_Overlay *bmp) {
    int i, width, height;
    Uint8 *p, *maxp;
    for (i = 0; i < 3; i++) {
        width  = bmp->w;
        height = bmp->h;
        if (i > 0) {
            width  >>= 1;
            height >>= 1;
        }
        if (bmp->pitches[i] > width) {
            maxp = bmp->pixels[i] + bmp->pitches[i] * height - 1;
            for (p = bmp->pixels[i] + width - 1; p < maxp; p += bmp->pitches[i])
                *(p+1) = *p;
        }
    }
}

static int queue_picture(VideoState *is, AVFrame *src_frame, double pts, int64_t pos, int serial)
{
    VideoPicture *vp;

#if defined(DEBUG_SYNC) && 0
    printf("frame_type=%c pts=%0.3f\n",
           av_get_picture_type_char(src_frame->pict_type), pts);
#endif

    /* wait until we have space to put a new picture */
    SDL_LockMutex(is->pictq_mutex);

    /* keep the last already displayed picture in the queue */
    while (is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE - 1 &&
           !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];

    vp->sar = src_frame->sample_aspect_ratio;

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

        vp->allocated  = 0;
        vp->reallocate = 0;
        vp->width = src_frame->width;
        vp->height = src_frame->height;

        /* 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);
        }
        /* if the queue is aborted, we have to pop the pending ALLOC event or wait for the allocation to complete */
        if (is->videoq.abort_request && SDL_PeepEvents(&event, 1, SDL_GETEVENT, SDL_EVENTMASK(FF_ALLOC_EVENT)) != 1) {
            while (!vp->allocated) {
                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 } };

        /* 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
        // FIXME use direct rendering
        av_picture_copy(&pict, (AVPicture *)src_frame,
                        src_frame->format, vp->width, vp->height);
#else
        av_opt_get_int(sws_opts, "sws_flags", 0, &sws_flags);
        is->img_convert_ctx = sws_getCachedContext(is->img_convert_ctx,
            vp->width, vp->height, src_frame->format, vp->width, vp->height,
            AV_PIX_FMT_YUV420P, 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
        /* workaround SDL PITCH_WORKAROUND */
        duplicate_right_border_pixels(vp->bmp);
        /* update the bitmap content */
        SDL_UnlockYUVOverlay(vp->bmp);

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

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

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

    if (packet_queue_get(&is->videoq, pkt, 1, serial) < 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 queue but that's harder)
        while (is->pictq_size && !is->videoq.abort_request) {
            SDL_CondWait(is->pictq_cond, is->pictq_mutex);
        }
        is->video_current_pos = -1;
        is->frame_last_pts = AV_NOPTS_VALUE;
        is->frame_last_duration = 0;
        is->frame_timer = (double)av_gettime() / 1000000.0;
        is->frame_last_dropped_pts = AV_NOPTS_VALUE;
        SDL_UnlockMutex(is->pictq_mutex);
        return 0;
    }

    if(avcodec_decode_video2(is->video_st->codec, frame, &got_picture, pkt) < 0)
        return 0;

    if (got_picture) {
        int ret = 1;
        double dpts = NAN;

        if (decoder_reorder_pts == -1) {
            frame->pts = av_frame_get_best_effort_timestamp(frame);
        } else if (decoder_reorder_pts) {
            frame->pts = frame->pkt_pts;
        } else {
            frame->pts = frame->pkt_dts;
        }

        if (frame->pts != AV_NOPTS_VALUE)
            dpts = av_q2d(is->video_st->time_base) * frame->pts;

        frame->sample_aspect_ratio = av_guess_sample_aspect_ratio(is->ic, is->video_st, frame);

        if (framedrop>0 || (framedrop && get_master_sync_type(is) != AV_SYNC_VIDEO_MASTER)) {
            SDL_LockMutex(is->pictq_mutex);
            if (is->frame_last_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE) {
                double clockdiff = get_clock(&is->vidclk) - get_master_clock(is);
                double ptsdiff = dpts - is->frame_last_pts;
                if (!isnan(clockdiff) && fabs(clockdiff) < AV_NOSYNC_THRESHOLD &&
                    !isnan(ptsdiff) && ptsdiff > 0 && ptsdiff < AV_NOSYNC_THRESHOLD &&
                    clockdiff + ptsdiff - is->frame_last_filter_delay < 0 &&
                    is->videoq.nb_packets) {
                    is->frame_last_dropped_pos = pkt->pos;
                    is->frame_last_dropped_pts = dpts;
                    is->frame_last_dropped_serial = *serial;
                    is->frame_drops_early++;
                    av_frame_unref(frame);
                    ret = 0;
                }
            }
            SDL_UnlockMutex(is->pictq_mutex);
        }

        return ret;
    }
    return 0;
}

#if CONFIG_AVFILTER
static int configure_filtergraph(AVFilterGraph *graph, const char *filtergraph,
                                 AVFilterContext *source_ctx, AVFilterContext *sink_ctx)
{
    int ret;
    AVFilterInOut *outputs = NULL, *inputs = NULL;

    if (filtergraph) {
        outputs = avfilter_inout_alloc();
        inputs  = avfilter_inout_alloc();
        if (!outputs || !inputs) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

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

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

        if ((ret = avfilter_graph_parse(graph, filtergraph, &inputs, &outputs, NULL)) < 0)
            goto fail;
    } else {
        if ((ret = avfilter_link(source_ctx, 0, sink_ctx, 0)) < 0)
            goto fail;
    }

    ret = avfilter_graph_config(graph, NULL);
fail:
    avfilter_inout_free(&outputs);
    avfilter_inout_free(&inputs);
    return ret;
}

static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const char *vfilters, AVFrame *frame)
{
    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE };
    char sws_flags_str[128];
    char buffersrc_args[256];
    int ret;
    AVFilterContext *filt_src = NULL, *filt_out = NULL, *filt_crop;
    AVCodecContext *codec = is->video_st->codec;
    AVRational fr = av_guess_frame_rate(is->ic, is->video_st, NULL);

    av_opt_get_int(sws_opts, "sws_flags", 0, &sws_flags);
    snprintf(sws_flags_str, sizeof(sws_flags_str), "flags=%"PRId64, sws_flags);
    graph->scale_sws_opts = av_strdup(sws_flags_str);

    snprintf(buffersrc_args, sizeof(buffersrc_args),
             "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
             frame->width, frame->height, frame->format,
             is->video_st->time_base.num, is->video_st->time_base.den,
             codec->sample_aspect_ratio.num, FFMAX(codec->sample_aspect_ratio.den, 1));
    if (fr.num && fr.den)
        av_strlcatf(buffersrc_args, sizeof(buffersrc_args), ":frame_rate=%d/%d", fr.num, fr.den);

    if ((ret = avfilter_graph_create_filter(&filt_src,
                                            avfilter_get_by_name("buffer"),
                                            "ffplay_buffer", buffersrc_args, NULL,
                                            graph)) < 0)
        goto fail;

    ret = avfilter_graph_create_filter(&filt_out,
                                       avfilter_get_by_name("buffersink"),
                                       "ffplay_buffersink", NULL, NULL, graph);
    if (ret < 0)
        goto fail;

    if ((ret = av_opt_set_int_list(filt_out, "pix_fmts", pix_fmts,  AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto fail;

    /* SDL YUV code is not handling odd width/height for some driver
     * combinations, therefore we crop the picture to an even width/height. */
    if ((ret = avfilter_graph_create_filter(&filt_crop,
                                            avfilter_get_by_name("crop"),
                                            "ffplay_crop", "floor(in_w/2)*2:floor(in_h/2)*2", NULL, graph)) < 0)
        goto fail;
    if ((ret = avfilter_link(filt_crop, 0, filt_out, 0)) < 0)
        goto fail;

    if ((ret = configure_filtergraph(graph, vfilters, filt_src, filt_crop)) < 0)
        goto fail;

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

fail:
    return ret;
}

static int configure_audio_filters(VideoState *is, const char *afilters, int force_output_format)
{
    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE };
    int sample_rates[2] = { 0, -1 };
    int64_t channel_layouts[2] = { 0, -1 };
    int channels[2] = { 0, -1 };
    AVFilterContext *filt_asrc = NULL, *filt_asink = NULL;
    char asrc_args[256];
    int ret;

    avfilter_graph_free(&is->agraph);
    if (!(is->agraph = avfilter_graph_alloc()))
        return AVERROR(ENOMEM);

    ret = snprintf(asrc_args, sizeof(asrc_args),
                   "sample_rate=%d:sample_fmt=%s:channels=%d:time_base=%d/%d",
                   is->audio_filter_src.freq, av_get_sample_fmt_name(is->audio_filter_src.fmt),
                   is->audio_filter_src.channels,
                   1, is->audio_filter_src.freq);
    if (is->audio_filter_src.channel_layout)
        snprintf(asrc_args + ret, sizeof(asrc_args) - ret,
                 ":channel_layout=0x%"PRIx64,  is->audio_filter_src.channel_layout);

    ret = avfilter_graph_create_filter(&filt_asrc,
                                       avfilter_get_by_name("abuffer"), "ffplay_abuffer",
                                       asrc_args, NULL, is->agraph);
    if (ret < 0)
        goto end;


    ret = avfilter_graph_create_filter(&filt_asink,
                                       avfilter_get_by_name("abuffersink"), "ffplay_abuffersink",
                                       NULL, NULL, is->agraph);
    if (ret < 0)
        goto end;

    if ((ret = av_opt_set_int_list(filt_asink, "sample_fmts", sample_fmts,  AV_SAMPLE_FMT_NONE, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto end;
    if ((ret = av_opt_set_int(filt_asink, "all_channel_counts", 1, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto end;

    if (force_output_format) {
        channel_layouts[0] = is->audio_tgt.channel_layout;
        channels       [0] = is->audio_tgt.channels;
        sample_rates   [0] = is->audio_tgt.freq;
        if ((ret = av_opt_set_int(filt_asink, "all_channel_counts", 0, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "channel_layouts", channel_layouts,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "channel_counts" , channels       ,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "sample_rates"   , sample_rates   ,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
    }


    if ((ret = configure_filtergraph(is->agraph, afilters, filt_asrc, filt_asink)) < 0)
        goto end;

    is->in_audio_filter  = filt_asrc;
    is->out_audio_filter = filt_asink;

end:
    if (ret < 0)
        avfilter_graph_free(&is->agraph);
    return ret;
}
#endif  /* CONFIG_AVFILTER */

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

#if CONFIG_AVFILTER
    AVFilterGraph *graph = avfilter_graph_alloc();
    AVFilterContext *filt_out = NULL, *filt_in = NULL;
    int last_w = 0;
    int last_h = 0;
    enum AVPixelFormat last_format = -2;
    int last_serial = -1;
#endif

    for (;;) {
        while (is->paused && !is->videoq.abort_request)
            SDL_Delay(10);

        avcodec_get_frame_defaults(frame);
        av_free_packet(&pkt);

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

#if CONFIG_AVFILTER
        if (   last_w != frame->width
            || last_h != frame->height
            || last_format != frame->format
            || last_serial != serial) {
            av_log(NULL, AV_LOG_DEBUG,
                   "Video frame changed from size:%dx%d format:%s serial:%d to size:%dx%d format:%s serial:%d\n",
                   last_w, last_h,
                   (const char *)av_x_if_null(av_get_pix_fmt_name(last_format), "none"), last_serial,
                   frame->width, frame->height,
                   (const char *)av_x_if_null(av_get_pix_fmt_name(frame->format), "none"), serial);
            avfilter_graph_free(&graph);
            graph = avfilter_graph_alloc();
            if ((ret = configure_video_filters(graph, is, vfilters, frame)) < 0) {
                SDL_Event event;
                event.type = FF_QUIT_EVENT;
                event.user.data1 = is;
                SDL_PushEvent(&event);
                av_free_packet(&pkt);
                goto the_end;
            }
            filt_in  = is->in_video_filter;
            filt_out = is->out_video_filter;
            last_w = frame->width;
            last_h = frame->height;
            last_format = frame->format;
            last_serial = serial;
        }

        ret = av_buffersrc_add_frame(filt_in, frame);
        if (ret < 0)
            goto the_end;
        av_frame_unref(frame);
        avcodec_get_frame_defaults(frame);
        av_free_packet(&pkt);

        while (ret >= 0) {
            is->frame_last_returned_time = av_gettime() / 1000000.0;

            ret = av_buffersink_get_frame_flags(filt_out, frame, 0);
            if (ret < 0) {
                ret = 0;
                break;
            }

            is->frame_last_filter_delay = av_gettime() / 1000000.0 - is->frame_last_returned_time;
            if (fabs(is->frame_last_filter_delay) > AV_NOSYNC_THRESHOLD / 10.0)
                is->frame_last_filter_delay = 0;

            pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(filt_out->inputs[0]->time_base);
            ret = queue_picture(is, frame, pts, av_frame_get_pkt_pos(frame), serial);
            av_frame_unref(frame);
        }
#else
        pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(is->video_st->time_base);
        ret = queue_picture(is, frame, pts, pkt.pos, serial);
        av_frame_unref(frame);
#endif

        if (ret < 0)
            goto the_end;
    }
 the_end:
    avcodec_flush_buffers(is->video_st->codec);
#if CONFIG_AVFILTER
    avfilter_graph_free(&graph);
#endif
    av_free_packet(&pkt);
    av_frame_free(&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, NULL) < 0)