ffplay.c

            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 wanted number of samples to get better sync if sync_type is video
 * or external master clock */
static int synchronize_audio(VideoState *is, int nb_samples)
{
    int wanted_nb_samples = nb_samples;

    /* if not master, then we try to remove or add samples to correct the clock */
    if (get_master_sync_type(is) != AV_SYNC_AUDIO_MASTER) {
        double diff, avg_diff;
        int min_nb_samples, max_nb_samples;

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

        if (fabs(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_nb_samples = nb_samples + (int)(diff * is->audio_src.freq);
                    min_nb_samples = ((nb_samples * (100 - SAMPLE_CORRECTION_PERCENT_MAX) / 100));
                    max_nb_samples = ((nb_samples * (100 + SAMPLE_CORRECTION_PERCENT_MAX) / 100));
                    wanted_nb_samples = FFMIN(FFMAX(wanted_nb_samples, min_nb_samples), max_nb_samples);
                }
                av_dlog(NULL, "diff=%f adiff=%f sample_diff=%d apts=%0.3f vpts=%0.3f %f\n",
                        diff, avg_diff, wanted_nb_samples - nb_samples,
                        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 wanted_nb_samples;
}

/**
 * Decode one audio frame and return its uncompressed size.
 *
 * The processed audio frame is decoded, converted if required, and
 * stored in is->audio_buf, with size in bytes given by the return
 * value.
 */
static int audio_decode_frame(VideoState *is)
{
    AVPacket *pkt_temp = &is->audio_pkt_temp;
    AVPacket *pkt = &is->audio_pkt;
    AVCodecContext *dec = is->audio_st->codec;
    int len1, len2, data_size, resampled_data_size;
    int64_t dec_channel_layout;
    int got_frame;
    av_unused double audio_clock0;
    int new_packet = 0;
    int flush_complete = 0;
    int wanted_nb_samples;

    for (;;) {
        /* NOTE: the audio packet can contain several frames */
        while (pkt_temp->size > 0 || (!pkt_temp->data && new_packet)) {
            if (!is->frame) {
                if (!(is->frame = avcodec_alloc_frame()))
                    return AVERROR(ENOMEM);
            } else
                avcodec_get_frame_defaults(is->frame);

            if (is->paused)
                return -1;

            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, is->frame->channels,
                                                   is->frame->nb_samples,
                                                   is->frame->format, 1);

            dec_channel_layout =
                (is->frame->channel_layout && is->frame->channels == av_get_channel_layout_nb_channels(is->frame->channel_layout)) ?
                is->frame->channel_layout : av_get_default_channel_layout(is->frame->channels);
            wanted_nb_samples = synchronize_audio(is, is->frame->nb_samples);

            if (is->frame->format        != is->audio_src.fmt            ||
                dec_channel_layout       != is->audio_src.channel_layout ||
                is->frame->sample_rate   != is->audio_src.freq           ||
                (wanted_nb_samples       != is->frame->nb_samples && !is->swr_ctx)) {
                swr_free(&is->swr_ctx);
                is->swr_ctx = swr_alloc_set_opts(NULL,
                                                 is->audio_tgt.channel_layout, is->audio_tgt.fmt, is->audio_tgt.freq,
                                                 dec_channel_layout,           is->frame->format, is->frame->sample_rate,
                                                 0, NULL);
                if (!is->swr_ctx || swr_init(is->swr_ctx) < 0) {
                    fprintf(stderr, "Cannot create sample rate converter for conversion of %d Hz %s %d channels to %d Hz %s %d channels!\n",
                        is->frame->sample_rate,   av_get_sample_fmt_name(is->frame->format), (int)is->frame->channels,
                        is->audio_tgt.freq, av_get_sample_fmt_name(is->audio_tgt.fmt), is->audio_tgt.channels);
                    break;
                }
                is->audio_src.channel_layout = dec_channel_layout;
                is->audio_src.channels = is->frame->channels;
                is->audio_src.freq = is->frame->sample_rate;
                is->audio_src.fmt = is->frame->format;
            }

            if (is->swr_ctx) {
                const uint8_t **in = (const uint8_t **)is->frame->extended_data;
                uint8_t **out = &is->audio_buf1;
                int out_count = (int64_t)wanted_nb_samples * is->audio_tgt.freq / is->frame->sample_rate + 256;
                int out_size  = av_samples_get_buffer_size(NULL, is->audio_tgt.channels, out_count, is->audio_tgt.fmt, 0);
                if (wanted_nb_samples != is->frame->nb_samples) {
                    if (swr_set_compensation(is->swr_ctx, (wanted_nb_samples - is->frame->nb_samples) * is->audio_tgt.freq / is->frame->sample_rate,
                                                wanted_nb_samples * is->audio_tgt.freq / is->frame->sample_rate) < 0) {
                        fprintf(stderr, "swr_set_compensation() failed\n");
                        break;
                    }
                }
                av_fast_malloc(&is->audio_buf1, &is->audio_buf1_size, out_size);
                if (!is->audio_buf1)
                    return AVERROR(ENOMEM);
                len2 = swr_convert(is->swr_ctx, out, out_count, in, is->frame->nb_samples);
                if (len2 < 0) {
                    fprintf(stderr, "swr_convert() failed\n");
                    break;
                }
                if (len2 == out_count) {
                    fprintf(stderr, "warning: audio buffer is probably too small\n");
                    swr_init(is->swr_ctx);
                }
                is->audio_buf = is->audio_buf1;
                resampled_data_size = len2 * is->audio_tgt.channels * av_get_bytes_per_sample(is->audio_tgt.fmt);
            } else {
                is->audio_buf = is->frame->data[0];
                resampled_data_size = data_size;
            }

            audio_clock0 = is->audio_clock;
            is->audio_clock += (double)data_size /
                (is->frame->channels * is->frame->sample_rate * av_get_bytes_per_sample(is->frame->format));
#ifdef DEBUG
            {
                static double last_clock;
                printf("audio: delay=%0.3f clock=%0.3f clock0=%0.3f\n",
                       is->audio_clock - last_clock,
                       is->audio_clock, audio_clock0);
                last_clock = is->audio_clock;
            }
#endif
            return resampled_data_size;
        }

        /* free the current packet */
        if (pkt->data)
            av_free_packet(pkt);
        memset(pkt_temp, 0, sizeof(*pkt_temp));

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

        if (is->audioq.nb_packets == 0)
            SDL_CondSignal(is->continue_read_thread);

        /* read next packet */
        if ((new_packet = packet_queue_get(&is->audioq, pkt, 1, &is->audio_pkt_temp_serial)) < 0)
            return -1;

        if (pkt->data == flush_pkt.data) {
            avcodec_flush_buffers(dec);
            flush_complete = 0;
        }

        *pkt_temp = *pkt;

        /* 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;
        }
    }
}

/* prepare a new audio buffer */
static void sdl_audio_callback(void *opaque, Uint8 *stream, int len)
{
    VideoState *is = opaque;
    int audio_size, len1;
    int bytes_per_sec;
    int frame_size = av_samples_get_buffer_size(NULL, is->audio_tgt.channels, 1, is->audio_tgt.fmt, 1);

    audio_callback_time = av_gettime();

    while (len > 0) {
        if (is->audio_buf_index >= is->audio_buf_size) {
           audio_size = audio_decode_frame(is);
           if (audio_size < 0) {
                /* if error, just output silence */
               is->audio_buf      = is->silence_buf;
               is->audio_buf_size = sizeof(is->silence_buf) / frame_size * frame_size;
           } else {
               if (is->show_mode != SHOW_MODE_VIDEO)
                   update_sample_display(is, (int16_t *)is->audio_buf, audio_size);
               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;
    }
    bytes_per_sec = is->audio_tgt.freq * is->audio_tgt.channels * av_get_bytes_per_sample(is->audio_tgt.fmt);
    is->audio_write_buf_size = is->audio_buf_size - is->audio_buf_index;
    /* Let's assume the audio driver that is used by SDL has two periods. */
    is->audio_current_pts = is->audio_clock - (double)(2 * is->audio_hw_buf_size + is->audio_write_buf_size) / bytes_per_sec;
    is->audio_current_pts_drift = is->audio_current_pts - audio_callback_time / 1000000.0;
    if (is->audioq.serial == is->audio_pkt_temp_serial)
        check_external_clock_sync(is, is->audio_current_pts);
}

static int audio_open(void *opaque, int64_t wanted_channel_layout, int wanted_nb_channels, int wanted_sample_rate, struct AudioParams *audio_hw_params)
{
    SDL_AudioSpec wanted_spec, spec;
    const char *env;
    const int next_nb_channels[] = {0, 0, 1, 6, 2, 6, 4, 6};

    env = SDL_getenv("SDL_AUDIO_CHANNELS");
    if (env) {
        wanted_nb_channels = atoi(env);
        wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
    }
    if (!wanted_channel_layout || wanted_nb_channels != av_get_channel_layout_nb_channels(wanted_channel_layout)) {
        wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
        wanted_channel_layout &= ~AV_CH_LAYOUT_STEREO_DOWNMIX;
    }
    wanted_spec.channels = av_get_channel_layout_nb_channels(wanted_channel_layout);
    wanted_spec.freq = wanted_sample_rate;
    if (wanted_spec.freq <= 0 || wanted_spec.channels <= 0) {
        fprintf(stderr, "Invalid sample rate or channel count!\n");
        return -1;
    }
    wanted_spec.format = AUDIO_S16SYS;
    wanted_spec.silence = 0;
    wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
    wanted_spec.callback = sdl_audio_callback;
    wanted_spec.userdata = opaque;
    while (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
        fprintf(stderr, "SDL_OpenAudio (%d channels): %s\n", wanted_spec.channels, SDL_GetError());
        wanted_spec.channels = next_nb_channels[FFMIN(7, wanted_spec.channels)];
        if (!wanted_spec.channels) {
            fprintf(stderr, "No more channel combinations to try, audio open failed\n");
            return -1;
        }
        wanted_channel_layout = av_get_default_channel_layout(wanted_spec.channels);
    }
    if (spec.format != AUDIO_S16SYS) {
        fprintf(stderr, "SDL advised audio format %d is not supported!\n", spec.format);
        return -1;
    }
    if (spec.channels != wanted_spec.channels) {
        wanted_channel_layout = av_get_default_channel_layout(spec.channels);
        if (!wanted_channel_layout) {
            fprintf(stderr, "SDL advised channel count %d is not supported!\n", spec.channels);
            return -1;
        }
    }

    audio_hw_params->fmt = AV_SAMPLE_FMT_S16;
    audio_hw_params->freq = spec.freq;
    audio_hw_params->channel_layout = wanted_channel_layout;
    audio_hw_params->channels =  spec.channels;
    return spec.size;
}

/* open a given stream. Return 0 if OK */
static int stream_component_open(VideoState *is, int stream_index)
{
    AVFormatContext *ic = is->ic;
    AVCodecContext *avctx;
    AVCodec *codec;
    const char *forced_codec_name = NULL;
    AVDictionary *opts;
    AVDictionaryEntry *t = NULL;

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

    codec = avcodec_find_decoder(avctx->codec_id);

    switch(avctx->codec_type){
        case AVMEDIA_TYPE_AUDIO   : is->last_audio_stream    = stream_index; forced_codec_name =    audio_codec_name; break;
        case AVMEDIA_TYPE_SUBTITLE: is->last_subtitle_stream = stream_index; forced_codec_name = subtitle_codec_name; break;
        case AVMEDIA_TYPE_VIDEO   : is->last_video_stream    = stream_index; forced_codec_name =    video_codec_name; break;
    }
    if (forced_codec_name)
        codec = avcodec_find_decoder_by_name(forced_codec_name);
    if (!codec) {
        if (forced_codec_name) fprintf(stderr, "No codec could be found with name '%s'\n", forced_codec_name);
        else                   fprintf(stderr, "No codec could be found with id %d\n", avctx->codec_id);
        return -1;
    }

    avctx->codec_id = codec->id;
    avctx->workaround_bugs   = workaround_bugs;
    avctx->lowres            = lowres;
    if(avctx->lowres > codec->max_lowres){
        av_log(avctx, AV_LOG_WARNING, "The maximum value for lowres supported by the decoder is %d\n",
                codec->max_lowres);
        avctx->lowres= codec->max_lowres;
    }
    avctx->idct_algo         = idct;
    avctx->skip_frame        = skip_frame;
    avctx->skip_idct         = skip_idct;
    avctx->skip_loop_filter  = skip_loop_filter;
    avctx->error_concealment = error_concealment;

    if(avctx->lowres) avctx->flags |= CODEC_FLAG_EMU_EDGE;
    if (fast)   avctx->flags2 |= CODEC_FLAG2_FAST;
    if(codec->capabilities & CODEC_CAP_DR1)
        avctx->flags |= CODEC_FLAG_EMU_EDGE;

    opts = filter_codec_opts(codec_opts, avctx->codec_id, ic, ic->streams[stream_index], codec);
    if (!av_dict_get(opts, "threads", NULL, 0))
        av_dict_set(&opts, "threads", "auto", 0);
    if (avcodec_open2(avctx, codec, &opts) < 0)
        return -1;
    if ((t = av_dict_get(opts, "", NULL, AV_DICT_IGNORE_SUFFIX))) {
        av_log(NULL, AV_LOG_ERROR, "Option %s not found.\n", t->key);
        return AVERROR_OPTION_NOT_FOUND;
    }

    /* prepare audio output */
    if (avctx->codec_type == AVMEDIA_TYPE_AUDIO) {
        int audio_hw_buf_size = audio_open(is, avctx->channel_layout, avctx->channels, avctx->sample_rate, &is->audio_src);
        if (audio_hw_buf_size < 0)
            return -1;
        is->audio_hw_buf_size = audio_hw_buf_size;
        is->audio_tgt = is->audio_src;
    }

    ic->streams[stream_index]->discard = AVDISCARD_DEFAULT;
    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        is->audio_stream = stream_index;
        is->audio_st = ic->streams[stream_index];
        is->audio_buf_size  = 0;
        is->audio_buf_index = 0;

        /* init averaging filter */
        is->audio_diff_avg_coef  = exp(log(0.01) / AUDIO_DIFF_AVG_NB);
        is->audio_diff_avg_count = 0;
        /* since we do not have a precise anough audio fifo fullness,
           we correct audio sync only if larger than this threshold */
        is->audio_diff_threshold = 2.0 * is->audio_hw_buf_size / av_samples_get_buffer_size(NULL, is->audio_tgt.channels, is->audio_tgt.freq, is->audio_tgt.fmt, 1);

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

        packet_queue_start(&is->videoq);
        is->video_tid = SDL_CreateThread(video_thread, is);
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        is->subtitle_stream = stream_index;
        is->subtitle_st = ic->streams[stream_index];
        packet_queue_start(&is->subtitleq);

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

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

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

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

        SDL_CloseAudio();

        packet_queue_flush(&is->audioq);
        av_free_packet(&is->audio_pkt);
        swr_free(&is->swr_ctx);
        av_freep(&is->audio_buf1);
        is->audio_buf1_size = 0;
        is->audio_buf = NULL;
        avcodec_free_frame(&is->frame);

        if (is->rdft) {
            av_rdft_end(is->rdft);
            av_freep(&is->rdft_data);
            is->rdft = NULL;
            is->rdft_bits = 0;
        }
        break;
    case AVMEDIA_TYPE_VIDEO:
        packet_queue_abort(&is->videoq);

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

        SDL_WaitThread(is->video_tid, NULL);

        packet_queue_flush(&is->videoq);
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        packet_queue_abort(&is->subtitleq);

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

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

        SDL_WaitThread(is->subtitle_tid, NULL);

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

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

static int decode_interrupt_cb(void *ctx)
{
    VideoState *is = ctx;
    return is->abort_request;
}

static int is_realtime(AVFormatContext *s)
{
    if(   !strcmp(s->iformat->name, "rtp")
       || !strcmp(s->iformat->name, "rtsp")
       || !strcmp(s->iformat->name, "sdp")
    )
        return 1;

    if(s->pb && (   !strncmp(s->filename, "rtp:", 4)
                 || !strncmp(s->filename, "udp:", 4)
                )
    )
        return 1;
    return 0;
}

/* this thread gets the stream from the disk or the network */
static int read_thread(void *arg)
{
    VideoState *is = arg;
    AVFormatContext *ic = NULL;
    int err, i, ret;
    int st_index[AVMEDIA_TYPE_NB];
    AVPacket pkt1, *pkt = &pkt1;
    int eof = 0;
    int pkt_in_play_range = 0;
    AVDictionaryEntry *t;
    AVDictionary **opts;
    int orig_nb_streams;
    SDL_mutex *wait_mutex = SDL_CreateMutex();

    memset(st_index, -1, sizeof(st_index));
    is->last_video_stream = is->video_stream = -1;
    is->last_audio_stream = is->audio_stream = -1;
    is->last_subtitle_stream = is->subtitle_stream = -1;

    ic = avformat_alloc_context();
    ic->interrupt_callback.callback = decode_interrupt_cb;
    ic->interrupt_callback.opaque = is;
    err = avformat_open_input(&ic, is->filename, is->iformat, &format_opts);
    if (err < 0) {
        print_error(is->filename, err);
        ret = -1;
        goto fail;
    }
    if ((t = av_dict_get(format_opts, "", NULL, AV_DICT_IGNORE_SUFFIX))) {
        av_log(NULL, AV_LOG_ERROR, "Option %s not found.\n", t->key);
        ret = AVERROR_OPTION_NOT_FOUND;
        goto fail;
    }
    is->ic = ic;

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

    opts = setup_find_stream_info_opts(ic, codec_opts);
    orig_nb_streams = ic->nb_streams;

    err = avformat_find_stream_info(ic, opts);
    if (err < 0) {
        fprintf(stderr, "%s: could not find codec parameters\n", is->filename);
        ret = -1;
        goto fail;
    }
    for (i = 0; i < orig_nb_streams; i++)
        av_dict_free(&opts[i]);
    av_freep(&opts);

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

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

    is->max_frame_duration = (ic->iformat->flags & AVFMT_TS_DISCONT) ? 10.0 : 3600.0;

    /* 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);
        }
    }

    is->realtime = is_realtime(ic);

    for (i = 0; i < ic->nb_streams; i++)
        ic->streams[i]->discard = AVDISCARD_ALL;
    if (!video_disable)
        st_index[AVMEDIA_TYPE_VIDEO] =
            av_find_best_stream(ic, AVMEDIA_TYPE_VIDEO,
                                wanted_stream[AVMEDIA_TYPE_VIDEO], -1, NULL, 0);
    if (!audio_disable)
        st_index[AVMEDIA_TYPE_AUDIO] =
            av_find_best_stream(ic, AVMEDIA_TYPE_AUDIO,
                                wanted_stream[AVMEDIA_TYPE_AUDIO],
                                st_index[AVMEDIA_TYPE_VIDEO],
                                NULL, 0);
    if (!video_disable)
        st_index[AVMEDIA_TYPE_SUBTITLE] =
            av_find_best_stream(ic, AVMEDIA_TYPE_SUBTITLE,
                                wanted_stream[AVMEDIA_TYPE_SUBTITLE],
                                (st_index[AVMEDIA_TYPE_AUDIO] >= 0 ?
                                 st_index[AVMEDIA_TYPE_AUDIO] :
                                 st_index[AVMEDIA_TYPE_VIDEO]),
                                NULL, 0);
    if (show_status) {
        av_dump_format(ic, 0, is->filename, 0);
    }

    is->show_mode = show_mode;

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

    ret = -1;
    if (st_index[AVMEDIA_TYPE_VIDEO] >= 0) {
        ret = stream_component_open(is, st_index[AVMEDIA_TYPE_VIDEO]);
    }
    if (is->show_mode == SHOW_MODE_NONE)
        is->show_mode = ret >= 0 ? SHOW_MODE_VIDEO : SHOW_MODE_RDFT;

    is->refresh_tid = SDL_CreateThread(refresh_thread, is);

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

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

    if (infinite_buffer < 0 && is->realtime)
        infinite_buffer = 1;

    for (;;) {
        if (is->abort_request)
            break;
        if (is->paused != is->last_paused) {
            is->last_paused = is->paused;
            if (is->paused)
                is->read_pause_return = av_read_pause(ic);
            else
                av_read_play(ic);
        }
#if CONFIG_RTSP_DEMUXER || CONFIG_MMSH_PROTOCOL
        if (is->paused &&
                (!strcmp(ic->iformat->name, "rtsp") ||
                 (ic->pb && !strncmp(input_filename, "mmsh:", 5)))) {
            /* wait 10 ms to avoid trying to get another packet */
            /* XXX: horrible */
            SDL_Delay(10);
            continue;
        }
#endif
        if (is->seek_req) {
            int64_t seek_target = is->seek_pos;
            int64_t seek_min    = is->seek_rel > 0 ? seek_target - is->seek_rel + 2: INT64_MIN;
            int64_t seek_max    = is->seek_rel < 0 ? seek_target - is->seek_rel - 2: INT64_MAX;
// FIXME the +-2 is due to rounding being not done in the correct direction in generation
//      of the seek_pos/seek_rel variables

            ret = avformat_seek_file(is->ic, -1, seek_min, seek_target, seek_max, is->seek_flags);
            if (ret < 0) {
                fprintf(stderr, "%s: error while seeking\n", is->ic->filename);
            } else {
                if (is->audio_stream >= 0) {
                    packet_queue_flush(&is->audioq);
                    packet_queue_put(&is->audioq, &flush_pkt);
                }
                if (is->subtitle_stream >= 0) {
                    packet_queue_flush(&is->subtitleq);
                    packet_queue_put(&is->subtitleq, &flush_pkt);
                }
                if (is->video_stream >= 0) {
                    packet_queue_flush(&is->videoq);
                    packet_queue_put(&is->videoq, &flush_pkt);
                }
                if (is->seek_flags & AVSEEK_FLAG_BYTE) {
                   //FIXME: use a cleaner way to signal obsolete external clock...
                   update_external_clock_pts(is, (double)AV_NOPTS_VALUE);
                } else {
                   update_external_clock_pts(is, seek_target / (double)AV_TIME_BASE);
                }
            }
            is->seek_req = 0;
            eof = 0;
            if (is->paused)
                step_to_next_frame(is);
        }
        if (is->queue_attachments_req) {
            avformat_queue_attached_pictures(ic);
            is->queue_attachments_req = 0;
        }

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

    ret = 0;
 fail:
    /* close each stream */
    if (is->audio_stream >= 0)
        stream_component_close(is, is->audio_stream);
    if (is->video_stream >= 0)
        stream_component_close(is, is->video_stream);
    if (is->subtitle_stream >= 0)
        stream_component_close(is, is->subtitle_stream);
    if (is->ic) {
        avformat_close_input(&is->ic);
    }

    if (ret != 0) {
        SDL_Event event;

        event.type = FF_QUIT_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);
    }
    SDL_DestroyMutex(wait_mutex);
    return 0;
}

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

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

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

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

    packet_queue_init(&is->videoq);
    packet_queue_init(&is->audioq);
    packet_queue_init(&is->subtitleq);

    is->continue_read_thread = SDL_CreateCond();

    //FIXME: use a cleaner way to signal obsolete external clock...
    update_external_clock_pts(is, (double)AV_NOPTS_VALUE);
    update_external_clock_speed(is, 1.0);
    is->audio_current_pts_drift = -av_gettime() / 1000000.0;
    is->video_current_pts_drift = is->audio_current_pts_drift;
    is->av_sync_type = av_sync_type;
    is->read_tid     = SDL_CreateThread(read_thread, is);
    if (!is->read_tid) {
        av_free(is);
        return NULL;
    }
    return is;
}

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

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


static void toggle_full_screen(VideoState *is)
{
#if defined(__APPLE__) && SDL_VERSION_ATLEAST(1, 2, 14)
    /* OS X needs to reallocate the SDL overlays */
    int i;
    for (i = 0; i < VIDEO_PICTURE_QUEUE_SIZE; i++)
        is->pictq[i].reallocate = 1;
#endif
    is_full_screen = !is_full_screen;
    video_open(is, 1, NULL);
}

static void toggle_audio_display(VideoState *is)
{
    int bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
    is->show_mode = (is->show_mode + 1) % SHOW_MODE_NB;
    fill_rectangle(screen,
                is->xleft, is->ytop, is->width, is->height,
                bgcolor, 1);
}

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

    for (;;) {
        double x;
        SDL_WaitEvent(&event);
        switch (event.type) {
        case SDL_KEYDOWN:
            if (exit_on_keydown) {
                do_exit(cur_stream);
                break;
            }
            switch (event.key.keysym.sym) {
            case SDLK_ESCAPE:
            case SDLK_q:
                do_exit(cur_stream);
                break;
            case SDLK_f:
                toggle_full_screen(cur_stream);
                cur_stream->force_refresh = 1;
                break;
            case SDLK_p:
            case SDLK_SPACE:
                toggle_pause(cur_stream);
                break;
            case SDLK_s: // S: Step to next frame
                step_to_next_frame(cur_stream);
                break;
            case SDLK_a:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_AUDIO);
                break;
            case SDLK_v:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_VIDEO);
                break;
            case SDLK_t:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_SUBTITLE);
                break;
            case SDLK_w:
                toggle_audio_display(cur_stream);