offset_t pos_min, pos_max;    int64_t pts_start;    offset_t ptr = url_ftell(pb);    pos_min = 0;    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;    pts_start = get_pts(s, pos_min);    pts = get_pts(s, pos_max);    if (pts - 100000 > pts_start)         goto end;    ffm->write_index = FFM_PACKET_SIZE;    pts_start = get_pts(s, pos_min);    pts = get_pts(s, pos_max);    if (pts - 100000 <= pts_start) {        while (1) {            offset_t newpos;            int64_t newpts;            newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;            if (newpos == pos_min)                break;            newpts = get_pts(s, newpos);            if (newpts - 100000 <= pts) {                pos_max = newpos;                pts = newpts;            } else {                pos_min = newpos;            }        }        ffm->write_index += pos_max;    }    //printf("Adjusted write index from %lld to %lld: pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);    //printf("pts range %0.6f - %0.6f\n", get_pts(s, 0) / 1000000. , get_pts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. ); end:    url_fseek(pb, ptr, SEEK_SET);}static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap){    FFMContext *ffm = s->priv_data;    AVStream *st;    FFMStream *fst;    ByteIOContext *pb = &s->pb;    AVCodecContext *codec;    int i, nb_streams;    uint32_t tag;    /* header */    tag = get_le32(pb);    if (tag != MKTAG('F', 'F', 'M', '1'))        goto fail;    ffm->packet_size = get_be32(pb);    if (ffm->packet_size != FFM_PACKET_SIZE)        goto fail;    ffm->write_index = get_be64(pb);    /* get also filesize */    if (!url_is_streamed(pb)) {        ffm->file_size = url_filesize(url_fileno(pb));        adjust_write_index(s);    } else {        ffm->file_size = (uint64_t_C(1) << 63) - 1;    }    nb_streams = get_be32(pb);    get_be32(pb); /* total bitrate */    /* read each stream */    for(i=0;i<nb_streams;i++) {        char rc_eq_buf[128];        st = av_new_stream(s, 0);        if (!st)            goto fail;        fst = av_mallocz(sizeof(FFMStream));        if (!fst)            goto fail;        st->priv_data = fst;        codec = &st->codec;        /* generic info */        st->codec.codec_id = get_be32(pb);        st->codec.codec_type = get_byte(pb); /* codec_type */        codec->bit_rate = get_be32(pb);	st->quality = get_be32(pb);        codec->flags = get_be32(pb);        /* specific info */        switch(codec->codec_type) {        case CODEC_TYPE_VIDEO:            codec->frame_rate_base = get_be32(pb);            codec->frame_rate = get_be32(pb);            codec->width = get_be16(pb);            codec->height = get_be16(pb);            codec->gop_size = get_be16(pb);            codec->qmin = get_byte(pb);            codec->qmax = get_byte(pb);            codec->max_qdiff = get_byte(pb);            codec->qcompress = get_be16(pb) / 10000.0;            codec->qblur = get_be16(pb) / 10000.0;            codec->bit_rate_tolerance = get_be32(pb);            codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));            codec->rc_max_rate = get_be32(pb);            codec->rc_min_rate = get_be32(pb);            codec->rc_buffer_size = get_be32(pb);            codec->i_quant_factor = get_be64_double(pb);            codec->b_quant_factor = get_be64_double(pb);            codec->i_quant_offset = get_be64_double(pb);            codec->b_quant_offset = get_be64_double(pb);            codec->dct_algo = get_be32(pb);            break;        case CODEC_TYPE_AUDIO:            codec->sample_rate = get_be32(pb);            codec->channels = get_le16(pb);            codec->frame_size = get_le16(pb);            break;        default:            goto fail;        }    }    /* get until end of block reached */    while ((url_ftell(pb) % ffm->packet_size) != 0)        get_byte(pb);    /* init packet demux */    ffm->packet_ptr = ffm->packet;    ffm->packet_end = ffm->packet;    ffm->frame_offset = 0;    ffm->pts = 0;    ffm->read_state = READ_HEADER;    ffm->first_packet = 1;    return 0; fail:    for(i=0;i<s->nb_streams;i++) {        st = s->streams[i];        if (st) {            av_freep(&st->priv_data);            av_free(st);        }    }    return -1;}/* return < 0 if eof */static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt){    int size;    FFMContext *ffm = s->priv_data;    int duration;    switch(ffm->read_state) {    case READ_HEADER:        if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE)) {            return -EAGAIN;        }#if 0        printf("pos=%08Lx spos=%Lx, write_index=%Lx size=%Lx\n",               url_ftell(&s->pb), s->pb.pos, ffm->write_index, ffm->file_size);#endif        if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=             FRAME_HEADER_SIZE)            return -EAGAIN;#if 0        {            int i;            for(i=0;i<FRAME_HEADER_SIZE;i++)                printf("%02x ", ffm->header[i]);            printf("\n");        }#endif        ffm->read_state = READ_DATA;        /* fall thru */    case READ_DATA:        size = (ffm->header[2] << 16) | (ffm->header[3] << 8) | ffm->header[4];        if (!ffm_is_avail_data(s, size)) {            return -EAGAIN;        }        duration = (ffm->header[5] << 16) | (ffm->header[6] << 8) | ffm->header[7];        av_new_packet(pkt, size);        pkt->stream_index = ffm->header[0];        if (ffm->header[1] & FLAG_KEY_FRAME)            pkt->flags |= PKT_FLAG_KEY;        ffm->read_state = READ_HEADER;        if (ffm_read_data(s, pkt->data, size, 0) != size) {            /* bad case: desynchronized packet. we cancel all the packet loading */            av_free_packet(pkt);            return -EAGAIN;        }        pkt->pts = ffm->pts;        pkt->duration = duration;        break;    }    return 0;}//#define DEBUG_SEEK/* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated   by the write position inside this function */static void ffm_seek1(AVFormatContext *s, offset_t pos1){    FFMContext *ffm = s->priv_data;    ByteIOContext *pb = &s->pb;    offset_t pos;    pos = pos1 + ffm->write_index;    if (pos >= ffm->file_size)        pos -= (ffm->file_size - FFM_PACKET_SIZE);#ifdef DEBUG_SEEK    printf("seek to %Lx -> %Lx\n", pos1, pos);#endif    url_fseek(pb, pos, SEEK_SET);}static int64_t get_pts(AVFormatContext *s, offset_t pos){    ByteIOContext *pb = &s->pb;    int64_t pts;    ffm_seek1(s, pos);    url_fskip(pb, 4);    pts = get_be64(pb);#ifdef DEBUG_SEEK    printf("pts=%0.6f\n", pts / 1000000.0);#endif    return pts;}/* seek to a given time in the file. The file read pointer is   positionned at or before pts. XXX: the following code is quite   approximative */static int ffm_seek(AVFormatContext *s, int64_t wanted_pts){    FFMContext *ffm = s->priv_data;    offset_t pos_min, pos_max, pos;    int64_t pts_min, pts_max, pts;    double pos1;#ifdef DEBUG_SEEK    printf("wanted_pts=%0.6f\n", wanted_pts / 1000000.0);#endif    /* find the position using linear interpolation (better than       dichotomy in typical cases) */    pos_min = 0;    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;    while (pos_min <= pos_max) {        pts_min = get_pts(s, pos_min);        pts_max = get_pts(s, pos_max);        /* linear interpolation */        pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /            (double)(pts_max - pts_min);        pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;        if (pos <= pos_min)            pos = pos_min;        else if (pos >= pos_max)            pos = pos_max;        pts = get_pts(s, pos);        /* check if we are lucky */        if (pts == wanted_pts) {            goto found;        } else if (pts > wanted_pts) {            pos_max = pos - FFM_PACKET_SIZE;        } else {            pos_min = pos + FFM_PACKET_SIZE;        }    }    pos = pos_min;    if (pos > 0)        pos -= FFM_PACKET_SIZE; found:    ffm_seek1(s, pos);    return 0;}offset_t ffm_read_write_index(int fd){    uint8_t buf[8];    offset_t pos;    int i;    lseek(fd, 8, SEEK_SET);    read(fd, buf, 8);    pos = 0;    for(i=0;i<8;i++)        pos |= (int64_t)buf[i] << (56 - i * 8);    return pos;}void ffm_write_write_index(int fd, offset_t pos){    uint8_t buf[8];    int i;    for(i=0;i<8;i++)        buf[i] = (pos >> (56 - i * 8)) & 0xff;    lseek(fd, 8, SEEK_SET);    write(fd, buf, 8);}void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size){    FFMContext *ffm = s->priv_data;    ffm->write_index = pos;    ffm->file_size = file_size;}static int ffm_read_close(AVFormatContext *s){    AVStream *st;    int i;    for(i=0;i<s->nb_streams;i++) {        st = s->streams[i];        av_freep(&st->priv_data);    }    return 0;}static int ffm_probe(AVProbeData *p){    if (p->buf_size >= 4 &&        p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&         p->buf[3] == '1')        return AVPROBE_SCORE_MAX + 1;    return 0;}static AVInputFormat ffm_iformat = {    "ffm",    "ffm format",    sizeof(FFMContext),    ffm_probe,    ffm_read_header,    ffm_read_packet,    ffm_read_close,    ffm_seek,};#ifdef CONFIG_ENCODERSstatic AVOutputFormat ffm_oformat = {    "ffm",    "ffm format",    "",    "ffm",    sizeof(FFMContext),    /* not really used */    CODEC_ID_MP2,    CODEC_ID_MPEG1VIDEO,    ffm_write_header,    ffm_write_packet,    ffm_write_trailer,};#endif //CONFIG_ENCODERSint ffm_init(void){    av_register_input_format(&ffm_iformat);#ifdef CONFIG_ENCODERS    av_register_output_format(&ffm_oformat);#endif //CONFIG_ENCODERS    return 0;}