utils.c

 * exactly one frame. For audio, it contains an integer number of
 * frames if each frame has a known fixed size (e.g. PCM or ADPCM
 * data). If the audio frames have a variable size (e.g. MPEG audio),
 * then it contains one frame.
 *
 * pkt->pts, pkt->dts and pkt->duration are always set to correct
 * values in AV_TIME_BASE unit (and guessed if the format cannot
 * provided them). pkt->pts can be AV_NOPTS_VALUE if the video format
 * has B frames, so it is better to rely on pkt->dts if you do not
 * decompress the payload.
 *
 * @return 0 if OK, < 0 if error or end of file.
 */
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
{
    AVPacketList *pktl;
    int eof=0;
    const int genpts= s->flags & AVFMT_FLAG_GENPTS;

    for(;;){
        pktl = s->packet_buffer;
        if (pktl) {
            AVPacket *next_pkt= &pktl->pkt;

            if(genpts && next_pkt->dts != AV_NOPTS_VALUE){
                while(pktl && next_pkt->pts == AV_NOPTS_VALUE){
                    if(   pktl->pkt.stream_index == next_pkt->stream_index
                       && next_pkt->dts < pktl->pkt.dts
                       && pktl->pkt.pts != pktl->pkt.dts //not b frame
                       /*&& pktl->pkt.dts != AV_NOPTS_VALUE*/){
                        next_pkt->pts= pktl->pkt.dts;
                    }
                    pktl= pktl->next;
                }
                pktl = s->packet_buffer;
            }

            if(   next_pkt->pts != AV_NOPTS_VALUE
               || next_pkt->dts == AV_NOPTS_VALUE
               || !genpts || eof){
                /* read packet from packet buffer, if there is data */
                *pkt = *next_pkt;
                s->packet_buffer = pktl->next;
                av_free(pktl);
                return 0;
            }
        }
        if(genpts){
            AVPacketList **plast_pktl= &s->packet_buffer;
            int ret= av_read_frame_internal(s, pkt);
            if(ret<0){
                if(pktl && ret != -EAGAIN){
                    eof=1;
                    continue;
                }else
                    return ret;
            }

            /* 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
 */
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 size, 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->size= size;
    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, 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 %"PRId64"\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%"PRIx64" dts_min=%"PRId64"\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%"PRIx64" pos_limit=0x%"PRIx64" dts_max=%"PRId64"\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;
    }

    if(ts_min > ts_max){
        return -1;
    }else if(ts_min == ts_max){
        pos_limit= pos_min;
    }

    no_change=0;
    while (pos_min < pos_limit) {
#ifdef DEBUG_SEEK
        av_log(s, AV_LOG_DEBUG, "pos_min=0x%"PRIx64" pos_max=0x%"PRIx64" dts_min=%"PRId64" dts_max=%"PRId64"\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, "%"PRId64" %"PRId64" %"PRId64" / %"PRId64" %"PRId64" %"PRId64" target:%"PRId64" limit:%"PRId64" start:%"PRId64" 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%"PRIx64" %"PRId64"<=%"PRId64"<=%"PRId64"\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 ((!strcmp(ic->iformat->name, "mpeg") ||
         !strcmp(ic->iformat->name, "mpegts")) &&
        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 * 3.0))

/**
 * 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, j;
    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);
            if(st->need_parsing == 2 && st->parser){
                st->parser->flags |= PARSER_FLAG_COMPLETE_FRAMES;
            }
        }
    }

    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 >= 101LL*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)){
                    char buf[256];
                    avcodec_string(buf, sizeof(buf), st->codec, 0);
                    av_log(ic, AV_LOG_INFO, "Could not find codec parameters (%s)\n", buf);
                } else {
                    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];