utils.c

            /* duplicate the packet */
            if (av_dup_packet(pkt) < 0)
                return AVERROR_NOMEM;

            while(*plast_pktl) plast_pktl= &(*plast_pktl)->next; //FIXME maybe maintain pointer to the last?
            
            pktl = av_mallocz(sizeof(AVPacketList));
            if (!pktl)
                return AVERROR_NOMEM;
    
            /* add the packet in the buffered packet list */
            *plast_pktl = pktl;
            pktl->pkt= *pkt;            
        }else{
            assert(!s->packet_buffer);
            return av_read_frame_internal(s, pkt);
        }
    }
}

/* XXX: suppress the packet queue */
static void flush_packet_queue(AVFormatContext *s)
{
    AVPacketList *pktl;

    for(;;) {
        pktl = s->packet_buffer;
        if (!pktl) 
            break;
        s->packet_buffer = pktl->next;
        av_free_packet(&pktl->pkt);
        av_free(pktl);
    }
}

/*******************************************************/
/* seek support */

int av_find_default_stream_index(AVFormatContext *s)
{
    int i;
    AVStream *st;

    if (s->nb_streams <= 0)
        return -1;
    for(i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        if (st->codec->codec_type == CODEC_TYPE_VIDEO) {
            return i;
        }
    }
    return 0;
}

/**
 * Flush the frame reader.
 */
static void av_read_frame_flush(AVFormatContext *s)
{
    AVStream *st;
    int i;

    flush_packet_queue(s);

    /* free previous packet */
    if (s->cur_st) {
        if (s->cur_st->parser)
            av_free_packet(&s->cur_pkt);
        s->cur_st = NULL;
    }
    /* fail safe */
    s->cur_ptr = NULL;
    s->cur_len = 0;
    
    /* for each stream, reset read state */
    for(i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        
        if (st->parser) {
            av_parser_close(st->parser);
            st->parser = NULL;
        }
        st->last_IP_pts = AV_NOPTS_VALUE;
        st->cur_dts = 0; /* we set the current DTS to an unspecified origin */
    }
}

/**
 * Updates cur_dts of all streams based on given timestamp and AVStream.
 *
 * Stream ref_st unchanged, others set cur_dts in their native timebase
 * only needed for timestamp wrapping or if (dts not set and pts!=dts)
 * @param timestamp new dts expressed in time_base of param ref_st
 * @param ref_st reference stream giving time_base of param timestamp
 */
static void av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp){
    int i;

    for(i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];

        st->cur_dts = av_rescale(timestamp, 
                                 st->time_base.den * (int64_t)ref_st->time_base.num,
                                 st->time_base.num * (int64_t)ref_st->time_base.den);
    }
}

/**
 * Add a index entry into a sorted list updateing if it is already there.
 *
 * @param timestamp timestamp in the timebase of the given stream
 */
int av_add_index_entry(AVStream *st,
                            int64_t pos, int64_t timestamp, int distance, int flags)
{
    AVIndexEntry *entries, *ie;
    int index;
    
    if((unsigned)st->nb_index_entries + 1 >= UINT_MAX / sizeof(AVIndexEntry))
        return -1;
    
    entries = av_fast_realloc(st->index_entries,
                              &st->index_entries_allocated_size,
                              (st->nb_index_entries + 1) * 
                              sizeof(AVIndexEntry));
    if(!entries)
        return -1;

    st->index_entries= entries;

    index= av_index_search_timestamp(st, timestamp, AVSEEK_FLAG_ANY);

    if(index<0){
        index= st->nb_index_entries++;
        ie= &entries[index];
        assert(index==0 || ie[-1].timestamp < timestamp);
    }else{
        ie= &entries[index];
        if(ie->timestamp != timestamp){
            if(ie->timestamp <= timestamp)
                return -1;
            memmove(entries + index + 1, entries + index, sizeof(AVIndexEntry)*(st->nb_index_entries - index));
            st->nb_index_entries++;
        }else if(ie->pos == pos && distance < ie->min_distance) //dont reduce the distance
            distance= ie->min_distance;
    }

    ie->pos = pos;
    ie->timestamp = timestamp;
    ie->min_distance= distance;
    ie->flags = flags;
    
    return index;
}

/**
 * build an index for raw streams using a parser.
 */
static void av_build_index_raw(AVFormatContext *s)
{
    AVPacket pkt1, *pkt = &pkt1;
    int ret;
    AVStream *st;

    st = s->streams[0];
    av_read_frame_flush(s);
    url_fseek(&s->pb, s->data_offset, SEEK_SET);

    for(;;) {
        ret = av_read_frame(s, pkt);
        if (ret < 0)
            break;
        if (pkt->stream_index == 0 && st->parser &&
            (pkt->flags & PKT_FLAG_KEY)) {
            av_add_index_entry(st, st->parser->frame_offset, pkt->dts, 
                            0, AVINDEX_KEYFRAME);
        }
        av_free_packet(pkt);
    }
}

/**
 * Returns TRUE if we deal with a raw stream.
 *
 * Raw codec data and parsing needed.
 */
static int is_raw_stream(AVFormatContext *s)
{
    AVStream *st;

    if (s->nb_streams != 1)
        return 0;
    st = s->streams[0];
    if (!st->need_parsing)
        return 0;
    return 1;
}

/**
 * Gets the index for a specific timestamp.
 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond to 
 *                 the timestamp which is <= the requested one, if backward is 0 
 *                 then it will be >=
 *              if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
 * @return < 0 if no such timestamp could be found
 */
int av_index_search_timestamp(AVStream *st, int64_t wanted_timestamp,
                              int flags)
{
    AVIndexEntry *entries= st->index_entries;
    int nb_entries= st->nb_index_entries;
    int a, b, m;
    int64_t timestamp;

    a = - 1;
    b = nb_entries;

    while (b - a > 1) {
        m = (a + b) >> 1;
        timestamp = entries[m].timestamp;
        if(timestamp >= wanted_timestamp)
            b = m;
        if(timestamp <= wanted_timestamp)
            a = m;
    }
    m= (flags & AVSEEK_FLAG_BACKWARD) ? a : b;
    
    if(!(flags & AVSEEK_FLAG_ANY)){
        while(m>=0 && m<nb_entries && !(entries[m].flags & AVINDEX_KEYFRAME)){
            m += (flags & AVSEEK_FLAG_BACKWARD) ? -1 : 1;
        }
    }

    if(m == nb_entries) 
        return -1;
    return  m;
}

#define DEBUG_SEEK

/**
 * Does a binary search using av_index_search_timestamp() and AVCodec.read_timestamp().
 * this isnt supposed to be called directly by a user application, but by demuxers
 * @param target_ts target timestamp in the time base of the given stream
 * @param stream_index stream number
 */
int av_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags){
    AVInputFormat *avif= s->iformat;
    int64_t pos_min, pos_max, pos, pos_limit;
    int64_t ts_min, ts_max, ts;
    int64_t start_pos, filesize;
    int index, no_change;
    AVStream *st;

    if (stream_index < 0)
        return -1;
    
#ifdef DEBUG_SEEK
    av_log(s, AV_LOG_DEBUG, "read_seek: %d %lld\n", stream_index, target_ts);
#endif

    ts_max=
    ts_min= AV_NOPTS_VALUE;
    pos_limit= -1; //gcc falsely says it may be uninitalized

    st= s->streams[stream_index];
    if(st->index_entries){
        AVIndexEntry *e;

        index= av_index_search_timestamp(st, target_ts, flags | AVSEEK_FLAG_BACKWARD); //FIXME whole func must be checked for non keyframe entries in index case, especially read_timestamp()
        index= FFMAX(index, 0);
        e= &st->index_entries[index];

        if(e->timestamp <= target_ts || e->pos == e->min_distance){
            pos_min= e->pos;
            ts_min= e->timestamp;
#ifdef DEBUG_SEEK
        av_log(s, AV_LOG_DEBUG, "using cached pos_min=0x%llx dts_min=%lld\n", 
               pos_min,ts_min);
#endif
        }else{
            assert(index==0);
        }
        
        index= av_index_search_timestamp(st, target_ts, flags & ~AVSEEK_FLAG_BACKWARD); 
        assert(index < st->nb_index_entries);
        if(index >= 0){
            e= &st->index_entries[index];
            assert(e->timestamp >= target_ts);
            pos_max= e->pos;
            ts_max= e->timestamp;
            pos_limit= pos_max - e->min_distance;
#ifdef DEBUG_SEEK
        av_log(s, AV_LOG_DEBUG, "using cached pos_max=0x%llx pos_limit=0x%llx dts_max=%lld\n", 
               pos_max,pos_limit, ts_max);
#endif
        }
    }

    if(ts_min == AV_NOPTS_VALUE){
        pos_min = s->data_offset;
        ts_min = avif->read_timestamp(s, stream_index, &pos_min, INT64_MAX);
        if (ts_min == AV_NOPTS_VALUE)
            return -1;
    }

    if(ts_max == AV_NOPTS_VALUE){
        int step= 1024;
        filesize = url_fsize(&s->pb);
        pos_max = filesize - 1;
        do{
            pos_max -= step;
            ts_max = avif->read_timestamp(s, stream_index, &pos_max, pos_max + step);
            step += step;
        }while(ts_max == AV_NOPTS_VALUE && pos_max >= step);
        if (ts_max == AV_NOPTS_VALUE)
            return -1;
        
        for(;;){
            int64_t tmp_pos= pos_max + 1;
            int64_t tmp_ts= avif->read_timestamp(s, stream_index, &tmp_pos, INT64_MAX);
            if(tmp_ts == AV_NOPTS_VALUE)
                break;
            ts_max= tmp_ts;
            pos_max= tmp_pos;
            if(tmp_pos >= filesize)
                break;
        }
        pos_limit= pos_max;
    }

    no_change=0;
    while (pos_min < pos_limit) {
#ifdef DEBUG_SEEK
        av_log(s, AV_LOG_DEBUG, "pos_min=0x%llx pos_max=0x%llx dts_min=%lld dts_max=%lld\n", 
               pos_min, pos_max,
               ts_min, ts_max);
#endif
        assert(pos_limit <= pos_max);

        if(no_change==0){
            int64_t approximate_keyframe_distance= pos_max - pos_limit;
            // interpolate position (better than dichotomy)
            pos = av_rescale(target_ts - ts_min, pos_max - pos_min, ts_max - ts_min)
                + pos_min - approximate_keyframe_distance;
        }else if(no_change==1){
            // bisection, if interpolation failed to change min or max pos last time
            pos = (pos_min + pos_limit)>>1;
        }else{
            // linear search if bisection failed, can only happen if there are very few or no keframes between min/max
            pos=pos_min;
        }
        if(pos <= pos_min)
            pos= pos_min + 1;
        else if(pos > pos_limit)
            pos= pos_limit;
        start_pos= pos;

        ts = avif->read_timestamp(s, stream_index, &pos, INT64_MAX); //may pass pos_limit instead of -1
        if(pos == pos_max)
            no_change++;
        else
            no_change=0;
#ifdef DEBUG_SEEK
av_log(s, AV_LOG_DEBUG, "%Ld %Ld %Ld / %Ld %Ld %Ld target:%Ld limit:%Ld start:%Ld noc:%d\n", pos_min, pos, pos_max, ts_min, ts, ts_max, target_ts, pos_limit, start_pos, no_change);
#endif
        assert(ts != AV_NOPTS_VALUE);
        if (target_ts <= ts) {
            pos_limit = start_pos - 1;
            pos_max = pos;
            ts_max = ts;
        }
        if (target_ts >= ts) {
            pos_min = pos;
            ts_min = ts;
        }
    }
    
    pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
    ts  = (flags & AVSEEK_FLAG_BACKWARD) ?  ts_min :  ts_max;
#ifdef DEBUG_SEEK
    pos_min = pos;
    ts_min = avif->read_timestamp(s, stream_index, &pos_min, INT64_MAX);
    pos_min++;
    ts_max = avif->read_timestamp(s, stream_index, &pos_min, INT64_MAX);
    av_log(s, AV_LOG_DEBUG, "pos=0x%llx %lld<=%lld<=%lld\n", 
           pos, ts_min, target_ts, ts_max);
#endif
    /* do the seek */
    url_fseek(&s->pb, pos, SEEK_SET);

    av_update_cur_dts(s, st, ts);

    return 0;
}

static int av_seek_frame_byte(AVFormatContext *s, int stream_index, int64_t pos, int flags){
    int64_t pos_min, pos_max;
#if 0
    AVStream *st;

    if (stream_index < 0)
        return -1;

    st= s->streams[stream_index];
#endif

    pos_min = s->data_offset;
    pos_max = url_fsize(&s->pb) - 1;

    if     (pos < pos_min) pos= pos_min;
    else if(pos > pos_max) pos= pos_max;

    url_fseek(&s->pb, pos, SEEK_SET);

#if 0
    av_update_cur_dts(s, st, ts);
#endif
    return 0;
}

static int av_seek_frame_generic(AVFormatContext *s, 
                                 int stream_index, int64_t timestamp, int flags)
{
    int index;
    AVStream *st;
    AVIndexEntry *ie;

    if (!s->index_built) {
        if (is_raw_stream(s)) {
            av_build_index_raw(s);
        } else {
            return -1;
        }
        s->index_built = 1;
    }

    st = s->streams[stream_index];
    index = av_index_search_timestamp(st, timestamp, flags);
    if (index < 0)
        return -1;

    /* now we have found the index, we can seek */
    ie = &st->index_entries[index];
    av_read_frame_flush(s);
    url_fseek(&s->pb, ie->pos, SEEK_SET);

    av_update_cur_dts(s, st, ie->timestamp);

    return 0;
}

/**
 * Seek to the key frame at timestamp.
 * 'timestamp' in 'stream_index'.
 * @param stream_index If stream_index is (-1), a default
 * stream is selected, and timestamp is automatically converted 
 * from AV_TIME_BASE units to the stream specific time_base.
 * @param timestamp timestamp in AVStream.time_base units
 *        or if there is no stream specified then in AV_TIME_BASE units
 * @param flags flags which select direction and seeking mode
 * @return >= 0 on success
 */
int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
    int ret;
    AVStream *st;
    
    av_read_frame_flush(s);
    
    if(flags & AVSEEK_FLAG_BYTE)
        return av_seek_frame_byte(s, stream_index, timestamp, flags);
    
    if(stream_index < 0){
        stream_index= av_find_default_stream_index(s);
        if(stream_index < 0)
            return -1;
            
        st= s->streams[stream_index];
       /* timestamp for default must be expressed in AV_TIME_BASE units */
        timestamp = av_rescale(timestamp, st->time_base.den, AV_TIME_BASE * (int64_t)st->time_base.num);
    }
    st= s->streams[stream_index];

    /* first, we try the format specific seek */
    if (s->iformat->read_seek)
        ret = s->iformat->read_seek(s, stream_index, timestamp, flags);
    else
        ret = -1;
    if (ret >= 0) {
        return 0;
    }

    if(s->iformat->read_timestamp)
        return av_seek_frame_binary(s, stream_index, timestamp, flags);
    else
        return av_seek_frame_generic(s, stream_index, timestamp, flags);
}

/*******************************************************/

/**
 * Returns TRUE if the stream has accurate timings in any stream.
 *
 * @return TRUE if the stream has accurate timings for at least one component.
 */
static int av_has_timings(AVFormatContext *ic)
{
    int i;
    AVStream *st;

    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->start_time != AV_NOPTS_VALUE &&
            st->duration != AV_NOPTS_VALUE)
            return 1;
    }
    return 0;
}

/**
 * Estimate the stream timings from the one of each components.
 *
 * Also computes the global bitrate if possible.
 */
static void av_update_stream_timings(AVFormatContext *ic)
{
    int64_t start_time, start_time1, end_time, end_time1;
    int i;
    AVStream *st;

    start_time = MAXINT64;
    end_time = MININT64;
    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->start_time != AV_NOPTS_VALUE) {
            start_time1= av_rescale_q(st->start_time, st->time_base, AV_TIME_BASE_Q);
            if (start_time1 < start_time)
                start_time = start_time1;
            if (st->duration != AV_NOPTS_VALUE) {
                end_time1 = start_time1
                          + av_rescale_q(st->duration, st->time_base, AV_TIME_BASE_Q);
                if (end_time1 > end_time)
                    end_time = end_time1;
            }
        }
    }
    if (start_time != MAXINT64) {
        ic->start_time = start_time;
        if (end_time != MININT64) {
            ic->duration = end_time - start_time;
            if (ic->file_size > 0) {
                /* compute the bit rate */
                ic->bit_rate = (double)ic->file_size * 8.0 * AV_TIME_BASE / 
                    (double)ic->duration;
            }
        }
    }

}

static void fill_all_stream_timings(AVFormatContext *ic)
{
    int i;
    AVStream *st;

    av_update_stream_timings(ic);
    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->start_time == AV_NOPTS_VALUE) {
            if(ic->start_time != AV_NOPTS_VALUE)
                st->start_time = av_rescale_q(ic->start_time, AV_TIME_BASE_Q, st->time_base);
            if(ic->duration != AV_NOPTS_VALUE)
                st->duration = av_rescale_q(ic->duration, AV_TIME_BASE_Q, st->time_base);
        }
    }
}

static void av_estimate_timings_from_bit_rate(AVFormatContext *ic)
{
    int64_t filesize, duration;
    int bit_rate, i;
    AVStream *st;

    /* if bit_rate is already set, we believe it */
    if (ic->bit_rate == 0) {
        bit_rate = 0;
        for(i=0;i<ic->nb_streams;i++) {
            st = ic->streams[i];
            bit_rate += st->codec->bit_rate;
        }
        ic->bit_rate = bit_rate;
    }

    /* if duration is already set, we believe it */
    if (ic->duration == AV_NOPTS_VALUE && 
        ic->bit_rate != 0 && 
        ic->file_size != 0)  {
        filesize = ic->file_size;
        if (filesize > 0) {
            for(i = 0; i < ic->nb_streams; i++) {
                st = ic->streams[i];
                duration= av_rescale(8*filesize, st->time_base.den, ic->bit_rate*(int64_t)st->time_base.num);
                if (st->start_time == AV_NOPTS_VALUE ||
                    st->duration == AV_NOPTS_VALUE) {
                    st->start_time = 0;
                    st->duration = duration;
                }
            }
        }
    }
}

#define DURATION_MAX_READ_SIZE 250000

/* only usable for MPEG-PS streams */
static void av_estimate_timings_from_pts(AVFormatContext *ic)
{
    AVPacket pkt1, *pkt = &pkt1;
    AVStream *st;
    int read_size, i, ret;
    int64_t end_time;
    int64_t filesize, offset, duration;
    
    /* free previous packet */
    if (ic->cur_st && ic->cur_st->parser)
        av_free_packet(&ic->cur_pkt); 
    ic->cur_st = NULL;

    /* flush packet queue */
    flush_packet_queue(ic);

    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if (st->parser) {
            av_parser_close(st->parser);
            st->parser= NULL;
        }
    }
    
    /* we read the first packets to get the first PTS (not fully
       accurate, but it is enough now) */
    url_fseek(&ic->pb, 0, SEEK_SET);
    read_size = 0;
    for(;;) {
        if (read_size >= DURATION_MAX_READ_SIZE)
            break;
        /* if all info is available, we can stop */
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
            if (st->start_time == AV_NOPTS_VALUE)
                break;
        }
        if (i == ic->nb_streams)
            break;

        ret = av_read_packet(ic, pkt);
        if (ret != 0)
            break;
        read_size += pkt->size;
        st = ic->streams[pkt->stream_index];
        if (pkt->pts != AV_NOPTS_VALUE) {
            if (st->start_time == AV_NOPTS_VALUE)
                st->start_time = pkt->pts;
        }
        av_free_packet(pkt);
    }

    /* estimate the end time (duration) */
    /* XXX: may need to support wrapping */
    filesize = ic->file_size;
    offset = filesize - DURATION_MAX_READ_SIZE;
    if (offset < 0)
        offset = 0;

    url_fseek(&ic->pb, offset, SEEK_SET);
    read_size = 0;
    for(;;) {
        if (read_size >= DURATION_MAX_READ_SIZE)
            break;
        /* if all info is available, we can stop */
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
            if (st->duration == AV_NOPTS_VALUE)
                break;
        }
        if (i == ic->nb_streams)
            break;
        
        ret = av_read_packet(ic, pkt);
        if (ret != 0)
            break;
        read_size += pkt->size;
        st = ic->streams[pkt->stream_index];
        if (pkt->pts != AV_NOPTS_VALUE) {
            end_time = pkt->pts;
            duration = end_time - st->start_time;
            if (duration > 0) {
                if (st->duration == AV_NOPTS_VALUE ||
                    st->duration < duration)
                    st->duration = duration;
            }
        }
        av_free_packet(pkt);
    }
    
    fill_all_stream_timings(ic);

    url_fseek(&ic->pb, 0, SEEK_SET);
}

static void av_estimate_timings(AVFormatContext *ic)
{
    int64_t file_size;

    /* get the file size, if possible */
    if (ic->iformat->flags & AVFMT_NOFILE) {
        file_size = 0;
    } else {
        file_size = url_fsize(&ic->pb);
        if (file_size < 0)
            file_size = 0;
    }
    ic->file_size = file_size;

    if ((ic->iformat == &mpegps_demux || ic->iformat == &mpegts_demux) && file_size && !ic->pb.is_streamed) {
        /* get accurate estimate from the PTSes */
        av_estimate_timings_from_pts(ic);
    } else if (av_has_timings(ic)) {
        /* at least one components has timings - we use them for all
           the components */
        fill_all_stream_timings(ic);
    } else {
        /* less precise: use bit rate info */
        av_estimate_timings_from_bit_rate(ic);
    }
    av_update_stream_timings(ic);

#if 0
    {
        int i;
        AVStream *st;
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
        printf("%d: start_time: %0.3f duration: %0.3f\n", 
               i, (double)st->start_time / AV_TIME_BASE, 
               (double)st->duration / AV_TIME_BASE);
        }
        printf("stream: start_time: %0.3f duration: %0.3f bitrate=%d kb/s\n", 
               (double)ic->start_time / AV_TIME_BASE, 
               (double)ic->duration / AV_TIME_BASE,
               ic->bit_rate / 1000);
    }
#endif
}

static int has_codec_parameters(AVCodecContext *enc)
{
    int val;
    switch(enc->codec_type) {
    case CODEC_TYPE_AUDIO:
        val = enc->sample_rate;
        break;
    case CODEC_TYPE_VIDEO:
        val = enc->width && enc->pix_fmt != PIX_FMT_NONE;
        break;
    default:
        val = 1;
        break;
    }
    return (val != 0);
}

static int try_decode_frame(AVStream *st, const uint8_t *data, int size)
{
    int16_t *samples;
    AVCodec *codec;
    int got_picture, ret=0;
    AVFrame picture;
    
  if(!st->codec->codec){
    codec = avcodec_find_decoder(st->codec->codec_id);
    if (!codec)
        return -1;
    ret = avcodec_open(st->codec, codec);
    if (ret < 0)
        return ret;
  }

  if(!has_codec_parameters(st->codec)){
    switch(st->codec->codec_type) {
    case CODEC_TYPE_VIDEO:
        ret = avcodec_decode_video(st->codec, &picture, 
                                   &got_picture, (uint8_t *)data, size);
        break;
    case CODEC_TYPE_AUDIO:
        samples = av_malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
        if (!samples)
            goto fail;
        ret = avcodec_decode_audio(st->codec, samples, 
                                   &got_picture, (uint8_t *)data, size);
        av_free(samples);
        break;
    default:
        break;
    }
  }
 fail:
    return ret;
}

/* absolute maximum size we read until we abort */
#define MAX_READ_SIZE        5000000

/* maximum duration until we stop analysing the stream */
#define MAX_STREAM_DURATION  ((int)(AV_TIME_BASE * 2.0))

/**
 * Read the beginning of a media file to get stream information. This
 * is useful for file formats with no headers such as MPEG. This
 * function also compute the real frame rate in case of mpeg2 repeat
 * frame mode.
 *
 * @param ic media file handle
 * @return >=0 if OK. AVERROR_xxx if error.  
 * @todo let user decide somehow what information is needed so we dont waste time geting stuff the user doesnt need
 */
int av_find_stream_info(AVFormatContext *ic)
{
    int i, count, ret, read_size;
    AVStream *st;
    AVPacket pkt1, *pkt;
    AVPacketList *pktl=NULL, **ppktl;
    int64_t last_dts[MAX_STREAMS];
    int64_t duration_sum[MAX_STREAMS];
    int duration_count[MAX_STREAMS]={0};

    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if(st->codec->codec_type == CODEC_TYPE_VIDEO){
/*            if(!st->time_base.num)
                st->time_base= */
            if(!st->codec->time_base.num)
                st->codec->time_base= st->time_base;
        }
        //only for the split stuff
        if (!st->parser) {
            st->parser = av_parser_init(st->codec->codec_id);
        }
    }

    for(i=0;i<MAX_STREAMS;i++){
        last_dts[i]= AV_NOPTS_VALUE;
        duration_sum[i]= INT64_MAX;
    }
    
    count = 0;
    read_size = 0;
    ppktl = &ic->packet_buffer;
    for(;;) {
        /* check if one codec still needs to be handled */
        for(i=0;i<ic->nb_streams;i++) {
            st = ic->streams[i];
            if (!has_codec_parameters(st->codec))
                break;
            /* variable fps and no guess at the real fps */
            if(   st->codec->time_base.den >= 1000LL*st->codec->time_base.num
               && duration_count[i]<20 && st->codec->codec_type == CODEC_TYPE_VIDEO)
                break;
            if(st->parser && st->parser->parser->split && !st->codec->extradata)
                break;
        }
        if (i == ic->nb_streams) {
            /* NOTE: if the format has no header, then we need to read
               some packets to get most of the streams, so we cannot
               stop here */
            if (!(ic->ctx_flags & AVFMTCTX_NOHEADER)) {
                /* if we found the info for all the codecs, we can stop */
                ret = count;
                break;
            }
        } else {
            /* we did not get all the codec info, but we read too much data */
            if (read_size >= MAX_READ_SIZE) {
                ret = count;
                break;
            }
        }

        /* NOTE: a new stream can be added there if no header in file
           (AVFMTCTX_NOHEADER) */
        ret = av_read_frame_internal(ic, &pkt1);
        if (ret < 0) {
            /* EOF or error */
            ret = -1; /* we could not have all the codec parameters before EOF */
            for(i=0;i<ic->nb_streams;i++) {
                st = ic->streams[i];
                if (!has_codec_parameters(st->codec))
                    break;
            }
            if (i == ic->nb_streams)
                ret = 0;
            break;
        }

        pktl = av_mallocz(sizeof(AVPacketList));
        if (!pktl) {
            ret = AVERROR_NOMEM;
            break;
        }

        /* add the packet in the buffered packet list */
        *ppktl = pktl;
        ppktl = &pktl->next;

        pkt = &pktl->pkt;
        *pkt = pkt1;
        
        /* duplicate the packet */
        if (av_dup_packet(pkt) < 0) {
                ret = AVERROR_NOMEM;
                break;
        }

        read_size += pkt->size;

        st = ic->streams[pkt->stream_index];
        st->codec_info_duration += pkt->duration;
        if (pkt->duration != 0)
            st->codec_info_nb_frames++;

        {
            int index= pkt->stream_index;
            int64_t last= last_dts[index];
            int64_t duration= pkt->dts - last;

            if(pkt->dts != AV_NOPTS_VALUE && last != AV_NOPTS_VALUE && duration>0){
                if(duration*duration_count[index]*10/9 < duration_sum[index]){
                    duration_sum[index]= duration;
                    duration_count[index]=1;
                }else{
                    int factor= av_rescale(duration, duration_count[index], duration_sum[index]);
                    duration_sum[index] += duration;
                    duration_count[index]+= factor;
                }
                if(st->codec_info_nb_frames == 0 && 0)
                    st->codec_info_duration += duration;
            }
            last_dts[pkt->stream_index]= pkt->dts;
        }
        if(st->parser && st->parser->parser->split && !st->codec->extradata){
            int i= st->parser->parser->split(st->codec, pkt->data, pkt->size);
            if(i){
                st->codec->extradata_size= i;
                st->codec->extradata= av_malloc(st->codec->extradata_size);
                memcpy(st->codec->extradata, pkt->data, st->codec->extradata_size);
            }
        }
        
        /* if still no information, we try to open the codec and to
           decompress the frame. We try to avoid that in most cases as
           it takes longer and uses more memory. For MPEG4, we need to
           decompress for Quicktime. */
        if (!has_codec_parameters(st->codec) /*&&
            (st->codec->codec_id == CODEC_ID_FLV1 ||
             st->codec->codec_id == CODEC_ID_H264 ||
             st->codec->codec_id == CODEC_ID_H263 ||
             st->codec->codec_id == CODEC_ID_H261 ||
             st->codec->codec_id == CODEC_ID_VORBIS ||
             st->codec->codec_id == CODEC_ID_MJPEG ||
             st->codec->codec_id == CODEC_ID_PNG ||
             st->codec->codec_id == CODEC_ID_PAM ||
             st->codec->codec_id == CODEC_ID_PGM ||
             st->codec->codec_id == CODEC_ID_PGMYUV ||
             st->codec->codec_id == CODEC_ID_PBM ||
             st->codec->codec_id == CODEC_ID_PPM ||
             st->codec->codec_id == CODEC_ID_SHORTEN ||
             (st->codec->codec_id == CODEC_ID_MPEG4 && !st->need_parsing))*/)
            try_decode_frame(st, pkt->data, pkt->size);
        
        if (av_rescale_q(st->codec_info_duration, st->time_base, AV_TIME_BASE_Q) >= MAX_STREAM_DURATION) {
            break;
        }
        count++;
    }

    // close codecs which where opened in try_decode_frame()
    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if(st->codec->codec)
            avcodec_close(st->codec);
    }
    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if (st->codec->codec_type == CODEC_TYPE_VIDEO) {
            if(st->codec->codec_id == CODEC_ID_RAWVIDEO && !st->codec->codec_tag && !st->codec->bits_per_sample)
                st->codec->codec_tag= avcodec_pix_fmt_to_codec_tag(st->codec->pix_fmt);

            if(duration_count[i] && st->codec->time_base.num*1000LL <= st->codec->time_base.den &&
               st->time_base.num*duration_sum[i]/duration_count[i]*1000LL > st->time_base.den){