PeerStreamer

/*

 * "Real" compatible demuxer.

 * Copyright (c) 2000, 2001 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/avstring.h"

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#include "riff.h"

#include "rm.h"

struct RMStream {

    AVPacket pkt;      ///< place to store merged video frame / reordered audio data

    int videobufsize;  ///< current assembled frame size

    int videobufpos;   ///< position for the next slice in the video buffer

    int curpic_num;    ///< picture number of current frame

    int cur_slice, slices;

    int64_t pktpos;    ///< first slice position in file

    /// Audio descrambling matrix parameters

    int64_t audiotimestamp; ///< Audio packet timestamp

    int sub_packet_cnt; // Subpacket counter, used while reading

    int sub_packet_size, sub_packet_h, coded_framesize; ///< Descrambling parameters from container

    int audio_framesize; /// Audio frame size from container

    int sub_packet_lengths[16]; /// Length of each subpacket

};

typedef struct {

    int nb_packets;

    int old_format;

    int current_stream;

    int remaining_len;

    int audio_stream_num; ///< Stream number for audio packets

    int audio_pkt_cnt; ///< Output packet counter

} RMDemuxContext;

static const unsigned char sipr_swaps[38][2] = {

    {  0, 63 }, {  1, 22 }, {  2, 44 }, {  3, 90 },

    {  5, 81 }, {  7, 31 }, {  8, 86 }, {  9, 58 },

    { 10, 36 }, { 12, 68 }, { 13, 39 }, { 14, 73 },

    { 15, 53 }, { 16, 69 }, { 17, 57 }, { 19, 88 },

    { 20, 34 }, { 21, 71 }, { 24, 46 }, { 25, 94 },

    { 26, 54 }, { 28, 75 }, { 29, 50 }, { 32, 70 },

    { 33, 92 }, { 35, 74 }, { 38, 85 }, { 40, 56 },

    { 42, 87 }, { 43, 65 }, { 45, 59 }, { 48, 79 },

    { 49, 93 }, { 51, 89 }, { 55, 95 }, { 61, 76 },

    { 67, 83 }, { 77, 80 }

};

const unsigned char ff_sipr_subpk_size[4] = { 29, 19, 37, 20 };

static inline void get_strl(AVIOContext *pb, char *buf, int buf_size, int len)

{

    int i;

    char *q, r;

    q = buf;

    for(i=0;i<len;i++) {

        r = avio_r8(pb);

        if (i < buf_size - 1)

            *q++ = r;

    }

    if (buf_size > 0) *q = '\0';

}

static void get_str8(AVIOContext *pb, char *buf, int buf_size)

{

    get_strl(pb, buf, buf_size, avio_r8(pb));

}

static int rm_read_extradata(AVIOContext *pb, AVCodecContext *avctx, unsigned size)

{

    if (size >= 1<<24)

        return -1;

    avctx->extradata = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);

    if (!avctx->extradata)

        return AVERROR(ENOMEM);

    avctx->extradata_size = avio_read(pb, avctx->extradata, size);

    memset(avctx->extradata + avctx->extradata_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);

    if (avctx->extradata_size != size)

        return AVERROR(EIO);

    return 0;

}

static void rm_read_metadata(AVFormatContext *s, int wide)

{

    char buf[1024];

    int i;

    for (i=0; i<FF_ARRAY_ELEMS(ff_rm_metadata); i++) {

        int len = wide ? avio_rb16(s->pb) : avio_r8(s->pb);

        get_strl(s->pb, buf, sizeof(buf), len);

        av_metadata_set2(&s->metadata, ff_rm_metadata[i], buf, 0);

    }

}

RMStream *ff_rm_alloc_rmstream (void)

{

    RMStream *rms = av_mallocz(sizeof(RMStream));

    rms->curpic_num = -1;

    return rms;

}

void ff_rm_free_rmstream (RMStream *rms)

{

    av_free_packet(&rms->pkt);

}

static int rm_read_audio_stream_info(AVFormatContext *s, AVIOContext *pb,

                                     AVStream *st, RMStream *ast, int read_all)

{

    char buf[256];

    uint32_t version;

    int ret;

    /* ra type header */

    version = avio_rb16(pb); /* version */

    if (version == 3) {

        int header_size = avio_rb16(pb);

        int64_t startpos = avio_tell(pb);

        avio_seek(pb, 14, SEEK_CUR);

        rm_read_metadata(s, 0);

        if ((startpos + header_size) >= avio_tell(pb) + 2) {

            // fourcc (should always be "lpcJ")

            avio_r8(pb);

            get_str8(pb, buf, sizeof(buf));

        }

        // Skip extra header crap (this should never happen)

        if ((startpos + header_size) > avio_tell(pb))

            avio_seek(pb, header_size + startpos - avio_tell(pb), SEEK_CUR);

        st->codec->sample_rate = 8000;

        st->codec->channels = 1;

        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

        st->codec->codec_id = CODEC_ID_RA_144;

    } else {

        int flavor, sub_packet_h, coded_framesize, sub_packet_size;

        int codecdata_length;

        /* old version (4) */

        avio_seek(pb, 2, SEEK_CUR); /* unused */

        avio_rb32(pb); /* .ra4 */

        avio_rb32(pb); /* data size */

        avio_rb16(pb); /* version2 */

        avio_rb32(pb); /* header size */

        flavor= avio_rb16(pb); /* add codec info / flavor */

        ast->coded_framesize = coded_framesize = avio_rb32(pb); /* coded frame size */

        avio_rb32(pb); /* ??? */

        avio_rb32(pb); /* ??? */

        avio_rb32(pb); /* ??? */

        ast->sub_packet_h = sub_packet_h = avio_rb16(pb); /* 1 */

        st->codec->block_align= avio_rb16(pb); /* frame size */

        ast->sub_packet_size = sub_packet_size = avio_rb16(pb); /* sub packet size */

        avio_rb16(pb); /* ??? */

        if (version == 5) {

            avio_rb16(pb); avio_rb16(pb); avio_rb16(pb);

        }

        st->codec->sample_rate = avio_rb16(pb);

        avio_rb32(pb);

        st->codec->channels = avio_rb16(pb);

        if (version == 5) {

            avio_rb32(pb);

            avio_read(pb, buf, 4);

            buf[4] = 0;

        } else {

            get_str8(pb, buf, sizeof(buf)); /* desc */

            get_str8(pb, buf, sizeof(buf)); /* desc */

        }

        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

        st->codec->codec_tag  = AV_RL32(buf);

        st->codec->codec_id   = ff_codec_get_id(ff_rm_codec_tags,

                                                st->codec->codec_tag);

        switch (st->codec->codec_id) {

        case CODEC_ID_AC3:

            st->need_parsing = AVSTREAM_PARSE_FULL;

            break;

        case CODEC_ID_RA_288:

            st->codec->extradata_size= 0;

            ast->audio_framesize = st->codec->block_align;

            st->codec->block_align = coded_framesize;

            if(ast->audio_framesize >= UINT_MAX / sub_packet_h){

                av_log(s, AV_LOG_ERROR, "ast->audio_framesize * sub_packet_h too large\n");

                return -1;

            }

            av_new_packet(&ast->pkt, ast->audio_framesize * sub_packet_h);

            break;

        case CODEC_ID_COOK:

        case CODEC_ID_ATRAC3:

        case CODEC_ID_SIPR:

            avio_rb16(pb); avio_r8(pb);

            if (version == 5)

                avio_r8(pb);

            codecdata_length = avio_rb32(pb);

            if(codecdata_length + FF_INPUT_BUFFER_PADDING_SIZE <= (unsigned)codecdata_length){

                av_log(s, AV_LOG_ERROR, "codecdata_length too large\n");

                return -1;

            }

            ast->audio_framesize = st->codec->block_align;

            if (st->codec->codec_id == CODEC_ID_SIPR) {

                if (flavor > 3) {

                    av_log(s, AV_LOG_ERROR, "bad SIPR file flavor %d\n",

                           flavor);

                    return -1;

                }

                st->codec->block_align = ff_sipr_subpk_size[flavor];

            } else {

                if(sub_packet_size <= 0){

                    av_log(s, AV_LOG_ERROR, "sub_packet_size is invalid\n");

                    return -1;

                }

                st->codec->block_align = ast->sub_packet_size;

            }

            if ((ret = rm_read_extradata(pb, st->codec, codecdata_length)) < 0)

                return ret;

            if(ast->audio_framesize >= UINT_MAX / sub_packet_h){

                av_log(s, AV_LOG_ERROR, "rm->audio_framesize * sub_packet_h too large\n");

                return -1;

            }

            av_new_packet(&ast->pkt, ast->audio_framesize * sub_packet_h);

            break;

        case CODEC_ID_AAC:

            avio_rb16(pb); avio_r8(pb);

            if (version == 5)

                avio_r8(pb);

            codecdata_length = avio_rb32(pb);

            if(codecdata_length + FF_INPUT_BUFFER_PADDING_SIZE <= (unsigned)codecdata_length){

                av_log(s, AV_LOG_ERROR, "codecdata_length too large\n");

                return -1;

            }

            if (codecdata_length >= 1) {

                avio_r8(pb);

                if ((ret = rm_read_extradata(pb, st->codec, codecdata_length - 1)) < 0)

                    return ret;

            }

            break;

        default:

            av_strlcpy(st->codec->codec_name, buf, sizeof(st->codec->codec_name));

        }

        if (read_all) {

            avio_r8(pb);

            avio_r8(pb);

            avio_r8(pb);

            rm_read_metadata(s, 0);

        }

    }

    return 0;

}

int

ff_rm_read_mdpr_codecdata (AVFormatContext *s, AVIOContext *pb,

                           AVStream *st, RMStream *rst, int codec_data_size)

{

    unsigned int v;

    int size;

    int64_t codec_pos;

    int ret;

    av_set_pts_info(st, 64, 1, 1000);

    codec_pos = avio_tell(pb);

    v = avio_rb32(pb);

    if (v == MKTAG(0xfd, 'a', 'r', '.')) {

        /* ra type header */

        if (rm_read_audio_stream_info(s, pb, st, rst, 0))

            return -1;

    } else {

        int fps, fps2;

        if (avio_rl32(pb) != MKTAG('V', 'I', 'D', 'O')) {

        fail1:

            av_log(st->codec, AV_LOG_ERROR, "Unsupported video codec\n");

            goto skip;

        }

        st->codec->codec_tag = avio_rl32(pb);

        st->codec->codec_id  = ff_codec_get_id(ff_rm_codec_tags,

                                               st->codec->codec_tag);

//        av_log(s, AV_LOG_DEBUG, "%X %X\n", st->codec->codec_tag, MKTAG('R', 'V', '2', '0'));

        if (st->codec->codec_id == CODEC_ID_NONE)

            goto fail1;

        st->codec->width = avio_rb16(pb);

        st->codec->height = avio_rb16(pb);

        st->codec->time_base.num= 1;

        fps= avio_rb16(pb);

        st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

        avio_rb32(pb);

        fps2= avio_rb16(pb);

        avio_rb16(pb);

        if ((ret = rm_read_extradata(pb, st->codec, codec_data_size - (avio_tell(pb) - codec_pos))) < 0)

            return ret;

//        av_log(s, AV_LOG_DEBUG, "fps= %d fps2= %d\n", fps, fps2);

        st->codec->time_base.den = fps * st->codec->time_base.num;

        //XXX: do we really need that?

        switch(st->codec->extradata[4]>>4){

        case 1: st->codec->codec_id = CODEC_ID_RV10; break;

        case 2: st->codec->codec_id = CODEC_ID_RV20; break;

        case 3: st->codec->codec_id = CODEC_ID_RV30; break;

        case 4: st->codec->codec_id = CODEC_ID_RV40; break;

        default:

            av_log(st->codec, AV_LOG_ERROR, "extra:%02X %02X %02X %02X %02X\n", st->codec->extradata[0], st->codec->extradata[1], st->codec->extradata[2], st->codec->extradata[3], st->codec->extradata[4]);

            goto fail1;

        }

    }

skip:

    /* skip codec info */

    size = avio_tell(pb) - codec_pos;

    avio_seek(pb, codec_data_size - size, SEEK_CUR);

    return 0;

}

/** this function assumes that the demuxer has already seeked to the start

 * of the INDX chunk, and will bail out if not. */

static int rm_read_index(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    unsigned int size, n_pkts, str_id, next_off, n, pos, pts;

    AVStream *st;

    do {

        if (avio_rl32(pb) != MKTAG('I','N','D','X'))

            return -1;

        size     = avio_rb32(pb);

        if (size < 20)

            return -1;

        avio_seek(pb, 2, SEEK_CUR);

        n_pkts   = avio_rb32(pb);

        str_id   = avio_rb16(pb);

        next_off = avio_rb32(pb);

        for (n = 0; n < s->nb_streams; n++)

            if (s->streams[n]->id == str_id) {

                st = s->streams[n];

                break;

            }

        if (n == s->nb_streams)

            goto skip;

        for (n = 0; n < n_pkts; n++) {

            avio_seek(pb, 2, SEEK_CUR);

            pts = avio_rb32(pb);

            pos = avio_rb32(pb);

            avio_seek(pb, 4, SEEK_CUR); /* packet no. */

            av_add_index_entry(st, pos, pts, 0, 0, AVINDEX_KEYFRAME);

        }

skip:

        if (next_off && avio_tell(pb) != next_off &&

            avio_seek(pb, next_off, SEEK_SET) < 0)

            return -1;

    } while (next_off);

    return 0;

}

static int rm_read_header_old(AVFormatContext *s, AVFormatParameters *ap)

{

    RMDemuxContext *rm = s->priv_data;

    AVStream *st;

    rm->old_format = 1;

    st = av_new_stream(s, 0);

    if (!st)

        return -1;

    st->priv_data = ff_rm_alloc_rmstream();

    return rm_read_audio_stream_info(s, s->pb, st, st->priv_data, 1);

}

static int rm_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    RMDemuxContext *rm = s->priv_data;

    AVStream *st;

    AVIOContext *pb = s->pb;

    unsigned int tag;

    int tag_size;

    unsigned int start_time, duration;

    unsigned int data_off = 0, indx_off = 0;

    char buf[128];

    int flags = 0;

    tag = avio_rl32(pb);

    if (tag == MKTAG('.', 'r', 'a', 0xfd)) {

        /* very old .ra format */

        return rm_read_header_old(s, ap);

    } else if (tag != MKTAG('.', 'R', 'M', 'F')) {

        return AVERROR(EIO);

    }

    avio_rb32(pb); /* header size */

    avio_rb16(pb);

    avio_rb32(pb);

    avio_rb32(pb); /* number of headers */

    for(;;) {

        if (url_feof(pb))

            return -1;

        tag = avio_rl32(pb);

        tag_size = avio_rb32(pb);

        avio_rb16(pb);

#if 0

        printf("tag=%c%c%c%c (%08x) size=%d\n",

               (tag) & 0xff,

               (tag >> 8) & 0xff,

               (tag >> 16) & 0xff,

               (tag >> 24) & 0xff,

               tag,

               tag_size);

#endif

        if (tag_size < 10 && tag != MKTAG('D', 'A', 'T', 'A'))

            return -1;

        switch(tag) {

        case MKTAG('P', 'R', 'O', 'P'):

            /* file header */

            avio_rb32(pb); /* max bit rate */

            avio_rb32(pb); /* avg bit rate */

            avio_rb32(pb); /* max packet size */

            avio_rb32(pb); /* avg packet size */

            avio_rb32(pb); /* nb packets */

            avio_rb32(pb); /* duration */

            avio_rb32(pb); /* preroll */

            indx_off = avio_rb32(pb); /* index offset */

            data_off = avio_rb32(pb); /* data offset */

            avio_rb16(pb); /* nb streams */

            flags = avio_rb16(pb); /* flags */

            break;

        case MKTAG('C', 'O', 'N', 'T'):

            rm_read_metadata(s, 1);

            break;

        case MKTAG('M', 'D', 'P', 'R'):

            st = av_new_stream(s, 0);

            if (!st)

                return AVERROR(ENOMEM);

            st->id = avio_rb16(pb);

            avio_rb32(pb); /* max bit rate */

            st->codec->bit_rate = avio_rb32(pb); /* bit rate */

            avio_rb32(pb); /* max packet size */

            avio_rb32(pb); /* avg packet size */

            start_time = avio_rb32(pb); /* start time */

            avio_rb32(pb); /* preroll */

            duration = avio_rb32(pb); /* duration */

            st->start_time = start_time;

            st->duration = duration;

            get_str8(pb, buf, sizeof(buf)); /* desc */

            get_str8(pb, buf, sizeof(buf)); /* mimetype */

            st->codec->codec_type = AVMEDIA_TYPE_DATA;

            st->priv_data = ff_rm_alloc_rmstream();

            if (ff_rm_read_mdpr_codecdata(s, s->pb, st, st->priv_data,

                                          avio_rb32(pb)) < 0)

                return -1;

            break;

        case MKTAG('D', 'A', 'T', 'A'):

            goto header_end;

        default:

            /* unknown tag: skip it */

            avio_seek(pb, tag_size - 10, SEEK_CUR);

            break;

        }

    }

 header_end:

    rm->nb_packets = avio_rb32(pb); /* number of packets */

    if (!rm->nb_packets && (flags & 4))

        rm->nb_packets = 3600 * 25;

    avio_rb32(pb); /* next data header */

    if (!data_off)

        data_off = avio_tell(pb) - 18;

    if (indx_off && !url_is_streamed(pb) && !(s->flags & AVFMT_FLAG_IGNIDX) &&

        avio_seek(pb, indx_off, SEEK_SET) >= 0) {

        rm_read_index(s);

        avio_seek(pb, data_off + 18, SEEK_SET);

    }

    return 0;

}

static int get_num(AVIOContext *pb, int *len)

{

    int n, n1;

    n = avio_rb16(pb);

    (*len)-=2;

    n &= 0x7FFF;

    if (n >= 0x4000) {

        return n - 0x4000;

    } else {

        n1 = avio_rb16(pb);

        (*len)-=2;

        return (n << 16) | n1;

    }

}

/* multiple of 20 bytes for ra144 (ugly) */

#define RAW_PACKET_SIZE 1000

static int sync(AVFormatContext *s, int64_t *timestamp, int *flags, int *stream_index, int64_t *pos){

    RMDemuxContext *rm = s->priv_data;

    AVIOContext *pb = s->pb;

    AVStream *st;

    uint32_t state=0xFFFFFFFF;

    while(!url_feof(pb)){

        int len, num, i;

        *pos= avio_tell(pb) - 3;

        if(rm->remaining_len > 0){

            num= rm->current_stream;

            len= rm->remaining_len;

            *timestamp = AV_NOPTS_VALUE;

            *flags= 0;

        }else{

            state= (state<<8) + avio_r8(pb);

            if(state == MKBETAG('I', 'N', 'D', 'X')){

                int n_pkts, expected_len;

                len = avio_rb32(pb);

                avio_seek(pb, 2, SEEK_CUR);

                n_pkts = avio_rb32(pb);

                expected_len = 20 + n_pkts * 14;

                if (len == 20)

                    /* some files don't add index entries to chunk size... */

                    len = expected_len;

                else if (len != expected_len)

                    av_log(s, AV_LOG_WARNING,

                           "Index size %d (%d pkts) is wrong, should be %d.\n",

                           len, n_pkts, expected_len);

                len -= 14; // we already read part of the index header

                if(len<0)

                    continue;

                goto skip;

            } else if (state == MKBETAG('D','A','T','A')) {

                av_log(s, AV_LOG_WARNING,

                       "DATA tag in middle of chunk, file may be broken.\n");

            }

            if(state > (unsigned)0xFFFF || state <= 12)

                continue;

            len=state - 12;

            state= 0xFFFFFFFF;

            num = avio_rb16(pb);

            *timestamp = avio_rb32(pb);

            avio_r8(pb); /* reserved */

            *flags = avio_r8(pb); /* flags */

        }

        for(i=0;i<s->nb_streams;i++) {

            st = s->streams[i];

            if (num == st->id)

                break;

        }

        if (i == s->nb_streams) {

skip:

            /* skip packet if unknown number */

            avio_seek(pb, len, SEEK_CUR);

            rm->remaining_len = 0;

            continue;

        }

        *stream_index= i;

        return len;

    }

    return -1;

}

static int rm_assemble_video_frame(AVFormatContext *s, AVIOContext *pb,

                                   RMDemuxContext *rm, RMStream *vst,

                                   AVPacket *pkt, int len, int *pseq)

{

    int hdr, seq, pic_num, len2, pos;

    int type;

    hdr = avio_r8(pb); len--;

    type = hdr >> 6;

    if(type != 3){  // not frame as a part of packet

        seq = avio_r8(pb); len--;

    }

    if(type != 1){  // not whole frame

        len2 = get_num(pb, &len);

        pos  = get_num(pb, &len);

        pic_num = avio_r8(pb); len--;

    }

    if(len<0)

        return -1;

    rm->remaining_len = len;

    if(type&1){     // frame, not slice

        if(type == 3)  // frame as a part of packet

            len= len2;

        if(rm->remaining_len < len)

            return -1;

        rm->remaining_len -= len;

        if(av_new_packet(pkt, len + 9) < 0)

            return AVERROR(EIO);

        pkt->data[0] = 0;

        AV_WL32(pkt->data + 1, 1);

        AV_WL32(pkt->data + 5, 0);

        avio_read(pb, pkt->data + 9, len);

        return 0;

    }

    //now we have to deal with single slice

    *pseq = seq;

    if((seq & 0x7F) == 1 || vst->curpic_num != pic_num){

        vst->slices = ((hdr & 0x3F) << 1) + 1;

        vst->videobufsize = len2 + 8*vst->slices + 1;

        av_free_packet(&vst->pkt); //FIXME this should be output.

        if(av_new_packet(&vst->pkt, vst->videobufsize) < 0)

            return AVERROR(ENOMEM);

        vst->videobufpos = 8*vst->slices + 1;

        vst->cur_slice = 0;

        vst->curpic_num = pic_num;

        vst->pktpos = avio_tell(pb);

    }

    if(type == 2)

        len = FFMIN(len, pos);

    if(++vst->cur_slice > vst->slices)

        return 1;

    AV_WL32(vst->pkt.data - 7 + 8*vst->cur_slice, 1);

    AV_WL32(vst->pkt.data - 3 + 8*vst->cur_slice, vst->videobufpos - 8*vst->slices - 1);

    if(vst->videobufpos + len > vst->videobufsize)

        return 1;

    if (avio_read(pb, vst->pkt.data + vst->videobufpos, len) != len)

        return AVERROR(EIO);

    vst->videobufpos += len;

    rm->remaining_len-= len;

    if(type == 2 || (vst->videobufpos) == vst->videobufsize){

        vst->pkt.data[0] = vst->cur_slice-1;

        *pkt= vst->pkt;

        vst->pkt.data= NULL;

        vst->pkt.size= 0;

        if(vst->slices != vst->cur_slice) //FIXME find out how to set slices correct from the begin

            memmove(pkt->data + 1 + 8*vst->cur_slice, pkt->data + 1 + 8*vst->slices,

                vst->videobufpos - 1 - 8*vst->slices);

        pkt->size = vst->videobufpos + 8*(vst->cur_slice - vst->slices);

        pkt->pts = AV_NOPTS_VALUE;

        pkt->pos = vst->pktpos;

        vst->slices = 0;

        return 0;

    }

    return 1;

}

static inline void

rm_ac3_swap_bytes (AVStream *st, AVPacket *pkt)

{

    uint8_t *ptr;

    int j;

    if (st->codec->codec_id == CODEC_ID_AC3) {

        ptr = pkt->data;

        for (j=0;j<pkt->size;j+=2) {

            FFSWAP(int, ptr[0], ptr[1]);

            ptr += 2;

        }

    }

}

/**

 * Perform 4-bit block reordering for SIPR data.

 * @todo This can be optimized, e.g. use memcpy() if data blocks are aligned

 */

void ff_rm_reorder_sipr_data(uint8_t *buf, int sub_packet_h, int framesize)

{

    int n, bs = sub_packet_h * framesize * 2 / 96; // nibbles per subpacket

    for (n = 0; n < 38; n++) {

        int j;

        int i = bs * sipr_swaps[n][0];

        int o = bs * sipr_swaps[n][1];

        /* swap 4bit-nibbles of block 'i' with 'o' */

        for (j = 0; j < bs; j++, i++, o++) {

            int x = (buf[i >> 1] >> (4 * (i & 1))) & 0xF,

                y = (buf[o >> 1] >> (4 * (o & 1))) & 0xF;

            buf[o >> 1] = (x << (4 * (o & 1))) |

                (buf[o >> 1] & (0xF << (4 * !(o & 1))));

            buf[i >> 1] = (y << (4 * (i & 1))) |

                (buf[i >> 1] & (0xF << (4 * !(i & 1))));

        }

    }

}

int

ff_rm_parse_packet (AVFormatContext *s, AVIOContext *pb,

                    AVStream *st, RMStream *ast, int len, AVPacket *pkt,

                    int *seq, int flags, int64_t timestamp)

{

    RMDemuxContext *rm = s->priv_data;

    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

        rm->current_stream= st->id;

        if(rm_assemble_video_frame(s, pb, rm, ast, pkt, len, seq))

            return -1; //got partial frame

    } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {

        if ((st->codec->codec_id == CODEC_ID_RA_288) ||

            (st->codec->codec_id == CODEC_ID_COOK) ||

            (st->codec->codec_id == CODEC_ID_ATRAC3) ||

            (st->codec->codec_id == CODEC_ID_SIPR)) {

            int x;

            int sps = ast->sub_packet_size;

            int cfs = ast->coded_framesize;

            int h = ast->sub_packet_h;

            int y = ast->sub_packet_cnt;

            int w = ast->audio_framesize;

            if (flags & 2)

                y = ast->sub_packet_cnt = 0;

            if (!y)

                ast->audiotimestamp = timestamp;

            switch(st->codec->codec_id) {

                case CODEC_ID_RA_288:

                    for (x = 0; x < h/2; x++)

                        avio_read(pb, ast->pkt.data+x*2*w+y*cfs, cfs);

                    break;

                case CODEC_ID_ATRAC3:

                case CODEC_ID_COOK:

                    for (x = 0; x < w/sps; x++)

                        avio_read(pb, ast->pkt.data+sps*(h*x+((h+1)/2)*(y&1)+(y>>1)), sps);

                    break;

                case CODEC_ID_SIPR:

                    avio_read(pb, ast->pkt.data + y * w, w);

                    break;

            }

            if (++(ast->sub_packet_cnt) < h)

                return -1;

            if (st->codec->codec_id == CODEC_ID_SIPR)

                ff_rm_reorder_sipr_data(ast->pkt.data, h, w);

             ast->sub_packet_cnt = 0;

             rm->audio_stream_num = st->index;

             rm->audio_pkt_cnt = h * w / st->codec->block_align;

        } else if (st->codec->codec_id == CODEC_ID_AAC) {

            int x;

            rm->audio_stream_num = st->index;

            ast->sub_packet_cnt = (avio_rb16(pb) & 0xf0) >> 4;

            if (ast->sub_packet_cnt) {

                for (x = 0; x < ast->sub_packet_cnt; x++)

                    ast->sub_packet_lengths[x] = avio_rb16(pb);

                rm->audio_pkt_cnt = ast->sub_packet_cnt;

                ast->audiotimestamp = timestamp;

            } else

                return -1;

        } else {

            av_get_packet(pb, pkt, len);

            rm_ac3_swap_bytes(st, pkt);

        }

    } else

        av_get_packet(pb, pkt, len);

    pkt->stream_index = st->index;

#if 0

    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

        if(st->codec->codec_id == CODEC_ID_RV20){

            int seq= 128*(pkt->data[2]&0x7F) + (pkt->data[3]>>1);

            av_log(s, AV_LOG_DEBUG, "%d %"PRId64" %d\n", *timestamp, *timestamp*512LL/25, seq);

            seq |= (timestamp&~0x3FFF);

            if(seq - timestamp >  0x2000) seq -= 0x4000;

            if(seq - timestamp < -0x2000) seq += 0x4000;

        }

    }

#endif

    pkt->pts= timestamp;

    if (flags & 2)

        pkt->flags |= AV_PKT_FLAG_KEY;

    return st->codec->codec_type == AVMEDIA_TYPE_AUDIO ? rm->audio_pkt_cnt : 0;

}

int

ff_rm_retrieve_cache (AVFormatContext *s, AVIOContext *pb,

                      AVStream *st, RMStream *ast, AVPacket *pkt)

{

    RMDemuxContext *rm = s->priv_data;

    assert (rm->audio_pkt_cnt > 0);

    if (st->codec->codec_id == CODEC_ID_AAC)

        av_get_packet(pb, pkt, ast->sub_packet_lengths[ast->sub_packet_cnt - rm->audio_pkt_cnt]);

    else {

        av_new_packet(pkt, st->codec->block_align);

        memcpy(pkt->data, ast->pkt.data + st->codec->block_align * //FIXME avoid this

               (ast->sub_packet_h * ast->audio_framesize / st->codec->block_align - rm->audio_pkt_cnt),

               st->codec->block_align);

    }

    rm->audio_pkt_cnt--;

    if ((pkt->pts = ast->audiotimestamp) != AV_NOPTS_VALUE) {

        ast->audiotimestamp = AV_NOPTS_VALUE;

        pkt->flags = AV_PKT_FLAG_KEY;

    } else

        pkt->flags = 0;

    pkt->stream_index = st->index;

    return rm->audio_pkt_cnt;

}

static int rm_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    RMDemuxContext *rm = s->priv_data;

    AVStream *st;

    int i, len, res, seq = 1;

    int64_t timestamp, pos;

    int flags;

    for (;;) {

        if (rm->audio_pkt_cnt) {

            // If there are queued audio packet return them first

            st = s->streams[rm->audio_stream_num];

            ff_rm_retrieve_cache(s, s->pb, st, st->priv_data, pkt);

            flags = 0;

        } else {

            if (rm->old_format) {

                RMStream *ast;

                st = s->streams[0];

                ast = st->priv_data;

                timestamp = AV_NOPTS_VALUE;

                len = !ast->audio_framesize ? RAW_PACKET_SIZE :

                    ast->coded_framesize * ast->sub_packet_h / 2;

                flags = (seq++ == 1) ? 2 : 0;

                pos = avio_tell(s->pb);

            } else {

                len=sync(s, &timestamp, &flags, &i, &pos);

                if (len > 0)

                    st = s->streams[i];

            }

            if(len<0 || url_feof(s->pb))

                return AVERROR(EIO);

            res = ff_rm_parse_packet (s, s->pb, st, st->priv_data, len, pkt,

                                      &seq, flags, timestamp);

            if((flags&2) && (seq&0x7F) == 1)

                av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);

            if (res)

                continue;

        }

        if(  (st->discard >= AVDISCARD_NONKEY && !(flags&2))

           || st->discard >= AVDISCARD_ALL){

            av_free_packet(pkt);

        } else

            break;

    }

    return 0;

}

static int rm_read_close(AVFormatContext *s)

{

    int i;

    for (i=0;i<s->nb_streams;i++)

        ff_rm_free_rmstream(s->streams[i]->priv_data);

    return 0;

}

static int rm_probe(AVProbeData *p)

{

    /* check file header */

    if ((p->buf[0] == '.' && p->buf[1] == 'R' &&

         p->buf[2] == 'M' && p->buf[3] == 'F' &&

         p->buf[4] == 0 && p->buf[5] == 0) ||

        (p->buf[0] == '.' && p->buf[1] == 'r' &&

         p->buf[2] == 'a' && p->buf[3] == 0xfd))

        return AVPROBE_SCORE_MAX;

    else

        return 0;

}

static int64_t rm_read_dts(AVFormatContext *s, int stream_index,

                               int64_t *ppos, int64_t pos_limit)

{

    RMDemuxContext *rm = s->priv_data;

    int64_t pos, dts;

    int stream_index2, flags, len, h;

    pos = *ppos;

    if(rm->old_format)

        return AV_NOPTS_VALUE;

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

    rm->remaining_len=0;

    for(;;){

        int seq=1;

        AVStream *st;

        len=sync(s, &dts, &flags, &stream_index2, &pos);

        if(len<0)

            return AV_NOPTS_VALUE;

        st = s->streams[stream_index2];

        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

            h= avio_r8(s->pb); len--;

            if(!(h & 0x40)){

                seq = avio_r8(s->pb); len--;

            }

        }

        if((flags&2) && (seq&0x7F) == 1){

//            av_log(s, AV_LOG_DEBUG, "%d %d-%d %"PRId64" %d\n", flags, stream_index2, stream_index, dts, seq);

            av_add_index_entry(st, pos, dts, 0, 0, AVINDEX_KEYFRAME);

            if(stream_index2 == stream_index)

                break;

        }

        avio_seek(s->pb, len, SEEK_CUR);

    }

    *ppos = pos;

    return dts;

}

AVInputFormat ff_rm_demuxer = {

    "rm",

    NULL_IF_CONFIG_SMALL("RealMedia format"),

    sizeof(RMDemuxContext),

    rm_probe,

    rm_read_header,

    rm_read_packet,

    rm_read_close,

    NULL,

    rm_read_dts,

};

AVInputFormat ff_rdt_demuxer = {

    "rdt",

    NULL_IF_CONFIG_SMALL("RDT demuxer"),

    sizeof(RMDemuxContext),

    NULL,

    NULL,

    NULL,

    rm_read_close,

};