static int ff_asf_parse_packet(AVFormatContext *s, ByteIOContext *pb, AVPacket *pkt)
{
    ASFContext *asf = s->priv_data;
    ASFStream *asf_st = 0;
    for (;;) {
        if(url_feof(pb))
            return AVERROR_EOF;
        if (asf->packet_size_left < FRAME_HEADER_SIZE
            || asf->packet_segments < 1) {
            //asf->packet_size_left <= asf->packet_padsize) {
            int ret = asf->packet_size_left + asf->packet_padsize;
            //printf("PacketLeftSize:%d  Pad:%d Pos:%"PRId64"\n", asf->packet_size_left, asf->packet_padsize, url_ftell(pb));
            assert(ret>=0);
            /* fail safe */
            url_fskip(pb, ret);

            asf->packet_pos= url_ftell(pb);
            if (asf->data_object_size != (uint64_t)-1 &&
                (asf->packet_pos - asf->data_object_offset >= asf->data_object_size))
                return AVERROR_EOF; /* Do not exceed the size of the data object */
            return 1;
        }
        if (asf->packet_time_start == 0) {
            if(asf_read_frame_header(s, pb) < 0){
                asf->packet_segments= 0;
                continue;
            }
            if (asf->stream_index < 0
                || s->streams[asf->stream_index]->discard >= AVDISCARD_ALL
                || (!asf->packet_key_frame && s->streams[asf->stream_index]->discard >= AVDISCARD_NONKEY)
                ) {
                asf->packet_time_start = 0;
                /* unhandled packet (should not happen) */
                url_fskip(pb, asf->packet_frag_size);
                asf->packet_size_left -= asf->packet_frag_size;
                if(asf->stream_index < 0)
                    av_log(s, AV_LOG_ERROR, "ff asf skip %d (unknown stream)\n", asf->packet_frag_size);
                continue;
            }
            asf->asf_st = s->streams[asf->stream_index]->priv_data;
        }
        asf_st = asf->asf_st;

        if (asf->packet_replic_size == 1) {
            // frag_offset is here used as the beginning timestamp
            asf->packet_frag_timestamp = asf->packet_time_start;
            asf->packet_time_start += asf->packet_time_delta;
            asf->packet_obj_size = asf->packet_frag_size = get_byte(pb);
            asf->packet_size_left--;
            asf->packet_multi_size--;
            if (asf->packet_multi_size < asf->packet_obj_size)
            {
                asf->packet_time_start = 0;
                url_fskip(pb, asf->packet_multi_size);
                asf->packet_size_left -= asf->packet_multi_size;
                continue;
            }
            asf->packet_multi_size -= asf->packet_obj_size;
            //printf("COMPRESS size  %d  %d  %d   ms:%d\n", asf->packet_obj_size, asf->packet_frag_timestamp, asf->packet_size_left, asf->packet_multi_size);
        }
        if(   /*asf->packet_frag_size == asf->packet_obj_size*/
              asf_st->frag_offset + asf->packet_frag_size <= asf_st->pkt.size
           && asf_st->frag_offset + asf->packet_frag_size > asf->packet_obj_size){
            av_log(s, AV_LOG_INFO, "ignoring invalid packet_obj_size (%d %d %d %d)\n",
                asf_st->frag_offset, asf->packet_frag_size,
                asf->packet_obj_size, asf_st->pkt.size);
            asf->packet_obj_size= asf_st->pkt.size;
        }

        if (   asf_st->pkt.size != asf->packet_obj_size
            || asf_st->frag_offset + asf->packet_frag_size > asf_st->pkt.size) { //FIXME is this condition sufficient?
            if(asf_st->pkt.data){
                av_log(s, AV_LOG_INFO, "freeing incomplete packet size %d, new %d\n", asf_st->pkt.size, asf->packet_obj_size);
                asf_st->frag_offset = 0;
                av_free_packet(&asf_st->pkt);
            }
            /* new packet */
            av_new_packet(&asf_st->pkt, asf->packet_obj_size);
            asf_st->seq = asf->packet_seq;
            asf_st->pkt.dts = asf->packet_frag_timestamp;
            asf_st->pkt.stream_index = asf->stream_index;
            asf_st->pkt.pos =
            asf_st->packet_pos= asf->packet_pos;
//printf("new packet: stream:%d key:%d packet_key:%d audio:%d size:%d\n",
//asf->stream_index, asf->packet_key_frame, asf_st->pkt.flags & PKT_FLAG_KEY,
//s->streams[asf->stream_index]->codec->codec_type == CODEC_TYPE_AUDIO, asf->packet_obj_size);
            if (s->streams[asf->stream_index]->codec->codec_type == CODEC_TYPE_AUDIO)
                asf->packet_key_frame = 1;
            if (asf->packet_key_frame)
                asf_st->pkt.flags |= PKT_FLAG_KEY;
        }

        /* read data */
        //printf("READ PACKET s:%d  os:%d  o:%d,%d  l:%d   DATA:%p\n",
        //       s->packet_size, asf_st->pkt.size, asf->packet_frag_offset,
        //       asf_st->frag_offset, asf->packet_frag_size, asf_st->pkt.data);
        asf->packet_size_left -= asf->packet_frag_size;
        if (asf->packet_size_left < 0)
            continue;

        if(   asf->packet_frag_offset >= asf_st->pkt.size
           || asf->packet_frag_size > asf_st->pkt.size - asf->packet_frag_offset){
            av_log(s, AV_LOG_ERROR, "packet fragment position invalid %u,%u not in %u\n",
                asf->packet_frag_offset, asf->packet_frag_size, asf_st->pkt.size);
            continue;
        }

        get_buffer(pb, asf_st->pkt.data + asf->packet_frag_offset,
                   asf->packet_frag_size);
        if (s->key && s->keylen == 20)
            ff_asfcrypt_dec(s->key, asf_st->pkt.data + asf->packet_frag_offset,
                            asf->packet_frag_size);
        asf_st->frag_offset += asf->packet_frag_size;
        /* test if whole packet is read */
        if (asf_st->frag_offset == asf_st->pkt.size) {
            //workaround for macroshit radio DVR-MS files
            if(   s->streams[asf->stream_index]->codec->codec_id == CODEC_ID_MPEG2VIDEO
               && asf_st->pkt.size > 100){
                int i;
                for(i=0; i<asf_st->pkt.size && !asf_st->pkt.data[i]; i++);
                if(i == asf_st->pkt.size){
                    av_log(s, AV_LOG_DEBUG, "discarding ms fart\n");
                    asf_st->frag_offset = 0;
                    av_free_packet(&asf_st->pkt);
                    continue;
                }
            }

            /* return packet */
            if (asf_st->ds_span > 1) {
              if(asf_st->pkt.size != asf_st->ds_packet_size * asf_st->ds_span){
                    av_log(s, AV_LOG_ERROR, "pkt.size != ds_packet_size * ds_span (%d %d %d)\n", asf_st->pkt.size, asf_st->ds_packet_size, asf_st->ds_span);
              }else{
                /* packet descrambling */
                uint8_t *newdata = av_malloc(asf_st->pkt.size);
                if (newdata) {
                    int offset = 0;
                    while (offset < asf_st->pkt.size) {
                        int off = offset / asf_st->ds_chunk_size;
                        int row = off / asf_st->ds_span;
                        int col = off % asf_st->ds_span;
                        int idx = row + col * asf_st->ds_packet_size / asf_st->ds_chunk_size;
                        //printf("off:%d  row:%d  col:%d  idx:%d\n", off, row, col, idx);

                        assert(offset + asf_st->ds_chunk_size <= asf_st->pkt.size);
                        assert(idx+1 <= asf_st->pkt.size / asf_st->ds_chunk_size);
                        memcpy(newdata + offset,
                               asf_st->pkt.data + idx * asf_st->ds_chunk_size,
                               asf_st->ds_chunk_size);
                        offset += asf_st->ds_chunk_size;
                    }
                    av_free(asf_st->pkt.data);
                    asf_st->pkt.data = newdata;
                }
              }
            }
            asf_st->frag_offset = 0;
            *pkt= asf_st->pkt;
            //printf("packet %d %d\n", asf_st->pkt.size, asf->packet_frag_size);
            asf_st->pkt.size = 0;
            asf_st->pkt.data = 0;
            break; // packet completed
        }
    }
    return 0;
}