utils.c

}

static void free_packet_buffer(AVPacketList **pkt_buf, AVPacketList **pkt_buf_end)
{
    while (*pkt_buf) {
        AVPacketList *pktl = *pkt_buf;
        *pkt_buf = pktl->next;
        av_free_packet(&pktl->pkt);
        av_freep(&pktl);
    }
    *pkt_buf_end = NULL;
}

static int read_from_packet_buffer(AVPacketList **pkt_buffer,
                                   AVPacketList **pkt_buffer_end,
                                   AVPacket      *pkt)
{
    AVPacketList *pktl;
    av_assert0(*pkt_buffer);
    pktl = *pkt_buffer;
    *pkt = pktl->pkt;
    *pkt_buffer = pktl->next;
    if (!pktl->next)
        *pkt_buffer_end = NULL;
    av_freep(&pktl);
    return 0;
}


static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
{
    AVStream *st;
    int len, ret, i;

    av_init_packet(pkt);

    for(;;) {
        /* select current input stream component */
        st = s->cur_st;
        if (st) {
            if (!st->need_parsing || !st->parser) {
                /* no parsing needed: we just output the packet as is */
                /* raw data support */
                *pkt = st->cur_pkt; st->cur_pkt.data= NULL;
                compute_pkt_fields(s, st, NULL, pkt);
                s->cur_st = NULL;
                if ((s->iformat->flags & AVFMT_GENERIC_INDEX) &&
                    (pkt->flags & AV_PKT_FLAG_KEY) && pkt->dts != AV_NOPTS_VALUE) {
                    ff_reduce_index(s, st->index);
                    av_add_index_entry(st, pkt->pos, pkt->dts, 0, 0, AVINDEX_KEYFRAME);
                }
                break;
            } else if (st->cur_len > 0 && st->discard < AVDISCARD_ALL) {
                len = av_parser_parse2(st->parser, st->codec, &pkt->data, &pkt->size,
                                       st->cur_ptr, st->cur_len,
                                       st->cur_pkt.pts, st->cur_pkt.dts,
                                       st->cur_pkt.pos);
                st->cur_pkt.pts = AV_NOPTS_VALUE;
                st->cur_pkt.dts = AV_NOPTS_VALUE;
                /* increment read pointer */
                st->cur_ptr += len;
                st->cur_len -= len;

                /* return packet if any */
                if (pkt->size) {
                got_packet:
                    pkt->duration = 0;
                    if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
                        if (st->codec->sample_rate > 0) {
                            pkt->duration = av_rescale_q_rnd(st->parser->duration,
                                                             (AVRational){ 1, st->codec->sample_rate },
                                                             st->time_base,
                                                             AV_ROUND_DOWN);
                        }
                    } else if (st->codec->time_base.num != 0 &&
                               st->codec->time_base.den != 0) {
                        pkt->duration = av_rescale_q_rnd(st->parser->duration,
                                                         st->codec->time_base,
                                                         st->time_base,
                                                         AV_ROUND_DOWN);
                    }
                    pkt->stream_index = st->index;
                    pkt->pts = st->parser->pts;
                    pkt->dts = st->parser->dts;
                    pkt->pos = st->parser->pos;
                    if (st->parser->key_frame == 1 ||
                        (st->parser->key_frame == -1 &&
                         st->parser->pict_type == AV_PICTURE_TYPE_I))
                        pkt->flags |= AV_PKT_FLAG_KEY;
                    if(pkt->data == st->cur_pkt.data && pkt->size == st->cur_pkt.size){
                        s->cur_st = NULL;
                        pkt->destruct= st->cur_pkt.destruct;
                        st->cur_pkt.destruct= NULL;
                        st->cur_pkt.data    = NULL;
                        assert(st->cur_len == 0);
                    }else{
                        pkt->destruct = NULL;
                    }
                    compute_pkt_fields(s, st, st->parser, pkt);

                    if((s->iformat->flags & AVFMT_GENERIC_INDEX) && pkt->flags & AV_PKT_FLAG_KEY){
                        ff_reduce_index(s, st->index);
                        av_add_index_entry(st, st->parser->frame_offset, pkt->dts,
                                           0, 0, AVINDEX_KEYFRAME);
                    }

                    break;
                }
            } else {
                /* free packet */
                av_free_packet(&st->cur_pkt);
                s->cur_st = NULL;
            }
        } else {
            AVPacket cur_pkt;
            /* read next packet */
            ret = av_read_packet(s, &cur_pkt);
            if (ret < 0) {
                if (ret == AVERROR(EAGAIN))
                    return ret;
                /* return the last frames, if any */
                for(i = 0; i < s->nb_streams; i++) {
                    st = s->streams[i];
                    if (st->parser && st->need_parsing) {
                        av_parser_parse2(st->parser, st->codec,
                                        &pkt->data, &pkt->size,
                                        NULL, 0,
                                        AV_NOPTS_VALUE, AV_NOPTS_VALUE,
                                        AV_NOPTS_VALUE);
                        if (pkt->size)
                            goto got_packet;
                    }
                }
                /* no more packets: really terminate parsing */
                return ret;
            }
            st = s->streams[cur_pkt.stream_index];
            st->cur_pkt= cur_pkt;

            if(st->cur_pkt.pts != AV_NOPTS_VALUE &&
               st->cur_pkt.dts != AV_NOPTS_VALUE &&
               st->cur_pkt.pts < st->cur_pkt.dts){
                av_log(s, AV_LOG_WARNING, "Invalid timestamps stream=%d, pts=%"PRId64", dts=%"PRId64", size=%d\n",
                    st->cur_pkt.stream_index,
                    st->cur_pkt.pts,
                    st->cur_pkt.dts,
                    st->cur_pkt.size);
//                av_free_packet(&st->cur_pkt);
//                return -1;
            }

            if(s->debug & FF_FDEBUG_TS)
                av_log(s, AV_LOG_DEBUG, "av_read_packet stream=%d, pts=%"PRId64", dts=%"PRId64", size=%d, duration=%d, flags=%d\n",
                    st->cur_pkt.stream_index,
                    st->cur_pkt.pts,
                    st->cur_pkt.dts,
                    st->cur_pkt.size,
                    st->cur_pkt.duration,
                    st->cur_pkt.flags);

            s->cur_st = st;
            st->cur_ptr = st->cur_pkt.data;
            st->cur_len = st->cur_pkt.size;
            if (st->need_parsing && !st->parser && !(s->flags & AVFMT_FLAG_NOPARSE)) {
                st->parser = av_parser_init(st->codec->codec_id);
                if (!st->parser) {
                    /* no parser available: just output the raw packets */
                    st->need_parsing = AVSTREAM_PARSE_NONE;
                }else if(st->need_parsing == AVSTREAM_PARSE_HEADERS){
                    st->parser->flags |= PARSER_FLAG_COMPLETE_FRAMES;
                }else if(st->need_parsing == AVSTREAM_PARSE_FULL_ONCE){
                    st->parser->flags |= PARSER_FLAG_ONCE;
                }
            }
        }
    }
    if(s->debug & FF_FDEBUG_TS)
        av_log(s, AV_LOG_DEBUG, "read_frame_internal stream=%d, pts=%"PRId64", dts=%"PRId64", size=%d, duration=%d, flags=%d\n",
            pkt->stream_index,
            pkt->pts,
            pkt->dts,
            pkt->size,
            pkt->duration,
            pkt->flags);

    return 0;
}

int av_read_frame(AVFormatContext *s, AVPacket *pkt)
{
    const int genpts = s->flags & AVFMT_FLAG_GENPTS;
    int          eof = 0;

    if (!genpts)
        return s->packet_buffer ? read_from_packet_buffer(&s->packet_buffer,
                                                          &s->packet_buffer_end,
                                                          pkt) :
                                  read_frame_internal(s, pkt);

    for (;;) {
        int ret;
        AVPacketList *pktl = s->packet_buffer;

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

            if (next_pkt->dts != AV_NOPTS_VALUE) {
                int wrap_bits = s->streams[next_pkt->stream_index]->pts_wrap_bits;
                while (pktl && next_pkt->pts == AV_NOPTS_VALUE) {
                    if (pktl->pkt.stream_index == next_pkt->stream_index &&
                        (av_compare_mod(next_pkt->dts, pktl->pkt.dts, 2LL << (wrap_bits - 1)) < 0) &&
                         av_compare_mod(pktl->pkt.pts, pktl->pkt.dts, 2LL << (wrap_bits - 1))) { //not b frame
                        next_pkt->pts = pktl->pkt.dts;
                    }
                    pktl = pktl->next;
                }
                pktl = s->packet_buffer;
            }

            /* read packet from packet buffer, if there is data */
            if (!(next_pkt->pts == AV_NOPTS_VALUE &&
                  next_pkt->dts != AV_NOPTS_VALUE && !eof))
                return read_from_packet_buffer(&s->packet_buffer,
                                               &s->packet_buffer_end, pkt);
        }

        ret = read_frame_internal(s, pkt);
        if (ret < 0) {
            if (pktl && ret != AVERROR(EAGAIN)) {
                eof = 1;
                continue;
            } else
                return ret;
        }

        if (av_dup_packet(add_to_pktbuf(&s->packet_buffer, pkt,
                          &s->packet_buffer_end)) < 0)
            return AVERROR(ENOMEM);
    }
}

/* XXX: suppress the packet queue */
static void flush_packet_queue(AVFormatContext *s)
{
    free_packet_buffer(&s->packet_buffer,     &s->packet_buffer_end);
    free_packet_buffer(&s->raw_packet_buffer, &s->raw_packet_buffer_end);

    s->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;
}

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

int av_find_default_stream_index(AVFormatContext *s)
{
    int first_audio_index = -1;
    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 == AVMEDIA_TYPE_VIDEO) {
            return i;
        }
        if (first_audio_index < 0 && st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
            first_audio_index = i;
    }
    return first_audio_index >= 0 ? first_audio_index : 0;
}

/**
 * Flush the frame reader.
 */
void ff_read_frame_flush(AVFormatContext *s)
{
    AVStream *st;
    int i, j;

    flush_packet_queue(s);

    s->cur_st = NULL;

    /* 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;
            av_free_packet(&st->cur_pkt);
        }
        st->last_IP_pts = AV_NOPTS_VALUE;
        st->cur_dts = AV_NOPTS_VALUE; /* we set the current DTS to an unspecified origin */
        st->reference_dts = AV_NOPTS_VALUE;
        /* fail safe */
        st->cur_ptr = NULL;
        st->cur_len = 0;

        st->probe_packets = MAX_PROBE_PACKETS;

        for(j=0; j<MAX_REORDER_DELAY+1; j++)
            st->pts_buffer[j]= AV_NOPTS_VALUE;
    }
}

void ff_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);
    }
}

void ff_reduce_index(AVFormatContext *s, int stream_index)
{
    AVStream *st= s->streams[stream_index];
    unsigned int max_entries= s->max_index_size / sizeof(AVIndexEntry);

    if((unsigned)st->nb_index_entries >= max_entries){
        int i;
        for(i=0; 2*i<st->nb_index_entries; i++)
            st->index_entries[i]= st->index_entries[2*i];
        st->nb_index_entries= i;
    }
}

int ff_add_index_entry(AVIndexEntry **index_entries,
                       int *nb_index_entries,
                       unsigned int *index_entries_allocated_size,
                       int64_t pos, int64_t timestamp, int size, int distance, int flags)
{
    AVIndexEntry *entries, *ie;
    int index;

    if((unsigned)*nb_index_entries + 1 >= UINT_MAX / sizeof(AVIndexEntry))
        return -1;

    entries = av_fast_realloc(*index_entries,
                              index_entries_allocated_size,
                              (*nb_index_entries + 1) *
                              sizeof(AVIndexEntry));
    if(!entries)
        return -1;

    *index_entries= entries;

    index= ff_index_search_timestamp(*index_entries, *nb_index_entries, timestamp, AVSEEK_FLAG_ANY);

    if(index<0){
        index= (*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)*(*nb_index_entries - index));
            (*nb_index_entries)++;
        }else if(ie->pos == pos && distance < ie->min_distance) //do not 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;
}

int av_add_index_entry(AVStream *st,
                       int64_t pos, int64_t timestamp, int size, int distance, int flags)
{
    return ff_add_index_entry(&st->index_entries, &st->nb_index_entries,
                              &st->index_entries_allocated_size, pos,
                              timestamp, size, distance, flags);
}

int ff_index_search_timestamp(const AVIndexEntry *entries, int nb_entries,
                              int64_t wanted_timestamp, int flags)
{
    int a, b, m;
    int64_t timestamp;

    a = - 1;
    b = nb_entries;

    //optimize appending index entries at the end
    if(b && entries[b-1].timestamp < wanted_timestamp)
        a= b-1;

    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;
}

int av_index_search_timestamp(AVStream *st, int64_t wanted_timestamp,
                              int flags)
{
    return ff_index_search_timestamp(st->index_entries, st->nb_index_entries,
                                     wanted_timestamp, flags);
}

int ff_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags)
{
    AVInputFormat *avif= s->iformat;
    int64_t av_uninit(pos_min), av_uninit(pos_max), pos, pos_limit;
    int64_t ts_min, ts_max, ts;
    int index;
    int64_t ret;
    AVStream *st;

    if (stream_index < 0)
        return -1;

    av_dlog(s, "read_seek: %d %"PRId64"\n", stream_index, target_ts);

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

    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;
            av_dlog(s, "using cached pos_min=0x%"PRIx64" dts_min=%"PRId64"\n",
                    pos_min,ts_min);
        }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;
            av_dlog(s, "using cached pos_max=0x%"PRIx64" pos_limit=0x%"PRIx64" dts_max=%"PRId64"\n",
                    pos_max,pos_limit, ts_max);
        }
    }

    pos= ff_gen_search(s, stream_index, target_ts, pos_min, pos_max, pos_limit, ts_min, ts_max, flags, &ts, avif->read_timestamp);
    if(pos<0)
        return -1;

    /* do the seek */
    if ((ret = avio_seek(s->pb, pos, SEEK_SET)) < 0)
        return ret;

    ff_update_cur_dts(s, st, ts);

    return 0;
}

int64_t ff_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts,
                      int64_t pos_min, int64_t pos_max, int64_t pos_limit,
                      int64_t ts_min, int64_t ts_max, int flags, int64_t *ts_ret,
                      int64_t (*read_timestamp)(struct AVFormatContext *, int , int64_t *, int64_t ))
{
    int64_t pos, ts;
    int64_t start_pos, filesize;
    int no_change;

    av_dlog(s, "gen_seek: %d %"PRId64"\n", stream_index, target_ts);

    if(ts_min == AV_NOPTS_VALUE){
        pos_min = s->data_offset;
        ts_min = 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 = avio_size(s->pb);
        pos_max = filesize - 1;
        do{
            pos_max -= step;
            ts_max = 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= 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) {
        av_dlog(s, "pos_min=0x%"PRIx64" pos_max=0x%"PRIx64" dts_min=%"PRId64" dts_max=%"PRId64"\n",
                pos_min, pos_max, ts_min, ts_max);
        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 keyframes 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 = 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;
        av_dlog(s, "%"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);
        if(ts == AV_NOPTS_VALUE){
            av_log(s, AV_LOG_ERROR, "read_timestamp() failed in the middle\n");
            return -1;
        }
        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;
    pos_min = pos;
    ts_min = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
    pos_min++;
    ts_max = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
    av_dlog(s, "pos=0x%"PRIx64" %"PRId64"<=%"PRId64"<=%"PRId64"\n",
            pos, ts_min, target_ts, ts_max);
    *ts_ret= ts;
    return pos;
}

static int 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 = avio_size(s->pb) - 1;

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

    avio_seek(s->pb, pos, SEEK_SET);

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

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

    st = s->streams[stream_index];

    index = av_index_search_timestamp(st, timestamp, flags);

    if(index < 0 && st->nb_index_entries && timestamp < st->index_entries[0].timestamp)
        return -1;

    if(index < 0 || index==st->nb_index_entries-1){
        AVPacket pkt;

        if(st->nb_index_entries){
            assert(st->index_entries);
            ie= &st->index_entries[st->nb_index_entries-1];
            if ((ret = avio_seek(s->pb, ie->pos, SEEK_SET)) < 0)
                return ret;
            ff_update_cur_dts(s, st, ie->timestamp);
        }else{
            if ((ret = avio_seek(s->pb, s->data_offset, SEEK_SET)) < 0)
                return ret;
        }
        for (;;) {
            int read_status;
            do{
                read_status = av_read_frame(s, &pkt);
            } while (read_status == AVERROR(EAGAIN));
            if (read_status < 0)
                break;
            av_free_packet(&pkt);
            if(stream_index == pkt.stream_index){
                if((pkt.flags & AV_PKT_FLAG_KEY) && pkt.dts > timestamp)
                    break;
            }
        }
        index = av_index_search_timestamp(st, timestamp, flags);
    }
    if (index < 0)
        return -1;

    ff_read_frame_flush(s);
    if (s->iformat->read_seek){
        if(s->iformat->read_seek(s, stream_index, timestamp, flags) >= 0)
            return 0;
    }
    ie = &st->index_entries[index];
    if ((ret = avio_seek(s->pb, ie->pos, SEEK_SET)) < 0)
        return ret;
    ff_update_cur_dts(s, st, ie->timestamp);

    return 0;
}

int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
    int ret;
    AVStream *st;

    if (flags & AVSEEK_FLAG_BYTE) {
        if (s->iformat->flags & AVFMT_NO_BYTE_SEEK)
            return -1;
        ff_read_frame_flush(s);
        return 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);
    }

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

    if (s->iformat->read_timestamp && !(s->iformat->flags & AVFMT_NOBINSEARCH)) {
        ff_read_frame_flush(s);
        return ff_seek_frame_binary(s, stream_index, timestamp, flags);
    } else if (!(s->iformat->flags & AVFMT_NOGENSEARCH)) {
        ff_read_frame_flush(s);
        return seek_frame_generic(s, stream_index, timestamp, flags);
    }
    else
        return -1;
}

int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
    if(min_ts > ts || max_ts < ts)
        return -1;

    if (s->iformat->read_seek2) {
        ff_read_frame_flush(s);
        return s->iformat->read_seek2(s, stream_index, min_ts, ts, max_ts, flags);
    }

    if(s->iformat->read_timestamp){
        //try to seek via read_timestamp()
    }

    //Fallback to old API if new is not implemented but old is
    //Note the old has somewat different sematics
    if(s->iformat->read_seek || 1)
        return av_seek_frame(s, stream_index, ts, flags | (ts - min_ts > (uint64_t)(max_ts - ts) ? AVSEEK_FLAG_BACKWARD : 0));

    // try some generic seek like seek_frame_generic() but with new ts semantics
}

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

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

    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (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 update_stream_timings(AVFormatContext *ic)
{
    int64_t start_time, start_time1, end_time, end_time1;
    int64_t duration, duration1, filesize;
    int i;
    AVStream *st;

    start_time = INT64_MAX;
    end_time = INT64_MIN;
    duration = INT64_MIN;
    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->start_time != AV_NOPTS_VALUE && st->time_base.den) {
            start_time1= av_rescale_q(st->start_time, st->time_base, AV_TIME_BASE_Q);
            start_time = FFMIN(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);
                end_time = FFMAX(end_time, end_time1);
            }
        }
        if (st->duration != AV_NOPTS_VALUE) {
            duration1 = av_rescale_q(st->duration, st->time_base, AV_TIME_BASE_Q);
            duration = FFMAX(duration, duration1);
        }
    }
    if (start_time != INT64_MAX) {
        ic->start_time = start_time;
        if (end_time != INT64_MIN)
            duration = FFMAX(duration, end_time - start_time);
    }
    if (duration != INT64_MIN) {
        ic->duration = duration;
        if (ic->pb && (filesize = avio_size(ic->pb)) > 0) {
            /* compute the bitrate */
            ic->bit_rate = (double)filesize * 8.0 * AV_TIME_BASE /
                (double)ic->duration;
        }
    }
}

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

    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 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];
            if (st->codec->bit_rate > 0)
            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) {
        filesize = ic->pb ? avio_size(ic->pb) : 0;
        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->duration == AV_NOPTS_VALUE)
                    st->duration = duration;
            }
        }
    }
}

#define DURATION_MAX_READ_SIZE 250000
#define DURATION_MAX_RETRY 3

/* only usable for MPEG-PS streams */
static void estimate_timings_from_pts(AVFormatContext *ic, int64_t old_offset)
{
    AVPacket pkt1, *pkt = &pkt1;
    AVStream *st;
    int read_size, i, ret;
    int64_t end_time;
    int64_t filesize, offset, duration;
    int retry=0;

    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->start_time == AV_NOPTS_VALUE && st->first_dts == AV_NOPTS_VALUE)
            av_log(st->codec, AV_LOG_WARNING, "start time is not set in estimate_timings_from_pts\n");

        if (st->parser) {
            av_parser_close(st->parser);
            st->parser= NULL;
            av_free_packet(&st->cur_pkt);
        }
    }

    /* estimate the end time (duration) */
    /* XXX: may need to support wrapping */
    filesize = ic->pb ? avio_size(ic->pb) : 0;
    end_time = AV_NOPTS_VALUE;
    do{
        offset = filesize - (DURATION_MAX_READ_SIZE<<retry);
        if (offset < 0)
            offset = 0;

        avio_seek(ic->pb, offset, SEEK_SET);
        read_size = 0;
        for(;;) {
            if (read_size >= DURATION_MAX_READ_SIZE<<(FFMAX(retry-1,0)))
                break;

            do {
                ret = av_read_packet(ic, pkt);
            } while(ret == AVERROR(EAGAIN));
            if (ret != 0)
                break;
            read_size += pkt->size;
            st = ic->streams[pkt->stream_index];
            if (pkt->pts != AV_NOPTS_VALUE &&
                (st->start_time != AV_NOPTS_VALUE ||
                 st->first_dts  != AV_NOPTS_VALUE)) {
                duration = end_time = pkt->pts;
                if (st->start_time != AV_NOPTS_VALUE)
                    duration -= st->start_time;
                else
                    duration -= st->first_dts;
                if (duration < 0)
                    duration += 1LL<<st->pts_wrap_bits;
                if (duration > 0) {
                    if (st->duration == AV_NOPTS_VALUE || st->duration < duration)
                        st->duration = duration;
                }
            }
            av_free_packet(pkt);
        }
    }while(   end_time==AV_NOPTS_VALUE
           && filesize > (DURATION_MAX_READ_SIZE<<retry)
           && ++retry <= DURATION_MAX_RETRY);

    fill_all_stream_timings(ic);

    avio_seek(ic->pb, old_offset, SEEK_SET);
    for (i=0; i<ic->nb_streams; i++) {
        st= ic->streams[i];
        st->cur_dts= st->first_dts;
        st->last_IP_pts = AV_NOPTS_VALUE;
        st->reference_dts = AV_NOPTS_VALUE;
    }
}

static void estimate_timings(AVFormatContext *ic, int64_t old_offset)
{
    int64_t file_size;

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

    if ((!strcmp(ic->iformat->name, "mpeg") ||
         !strcmp(ic->iformat->name, "mpegts")) &&
        file_size && ic->pb->seekable) {
        /* get accurate estimate from the PTSes */
        estimate_timings_from_pts(ic, old_offset);
    } else if (has_duration(ic)) {
        /* at least one component has timings - we use them for all
           the components */
        fill_all_stream_timings(ic);
    } else {
        av_log(ic, AV_LOG_WARNING, "Estimating duration from bitrate, this may be inaccurate\n");
        /* less precise: use bitrate info */
        estimate_timings_from_bit_rate(ic);
    }
    update_stream_timings(ic);

    {
        int i;
        AVStream av_unused *st;
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
            av_dlog(ic, "%d: start_time: %0.3f duration: %0.3f\n", i,
                    (double) st->start_time / AV_TIME_BASE,
                    (double) st->duration   / AV_TIME_BASE);
        }
        av_dlog(ic, "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);
    }
}

static int has_codec_parameters(AVCodecContext *avctx)
{
    int val;
    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        val = avctx->sample_rate && avctx->channels && avctx->sample_fmt != AV_SAMPLE_FMT_NONE;
        if (!avctx->frame_size &&
            (avctx->codec_id == CODEC_ID_AAC ||
             avctx->codec_id == CODEC_ID_MP1 ||