PeerStreamer

/*

 * 4X Technologies .4xm File Demuxer (no muxer)

 * Copyright (c) 2003  The ffmpeg Project

 *

 * 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

 */

/**

 * @file

 * 4X Technologies file demuxer

 * by Mike Melanson (melanson@pcisys.net)

 * for more information on the .4xm file format, visit:

 *   http://www.pcisys.net/~melanson/codecs/

 */

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#define     RIFF_TAG MKTAG('R', 'I', 'F', 'F')

#define  FOURXMV_TAG MKTAG('4', 'X', 'M', 'V')

#define     LIST_TAG MKTAG('L', 'I', 'S', 'T')

#define     HEAD_TAG MKTAG('H', 'E', 'A', 'D')

#define     TRK__TAG MKTAG('T', 'R', 'K', '_')

#define     MOVI_TAG MKTAG('M', 'O', 'V', 'I')

#define     VTRK_TAG MKTAG('V', 'T', 'R', 'K')

#define     STRK_TAG MKTAG('S', 'T', 'R', 'K')

#define     std__TAG MKTAG('s', 't', 'd', '_')

#define     name_TAG MKTAG('n', 'a', 'm', 'e')

#define     vtrk_TAG MKTAG('v', 't', 'r', 'k')

#define     strk_TAG MKTAG('s', 't', 'r', 'k')

#define     ifrm_TAG MKTAG('i', 'f', 'r', 'm')

#define     pfrm_TAG MKTAG('p', 'f', 'r', 'm')

#define     cfrm_TAG MKTAG('c', 'f', 'r', 'm')

#define     ifr2_TAG MKTAG('i', 'f', 'r', '2')

#define     pfr2_TAG MKTAG('p', 'f', 'r', '2')

#define     cfr2_TAG MKTAG('c', 'f', 'r', '2')

#define     snd__TAG MKTAG('s', 'n', 'd', '_')

#define vtrk_SIZE 0x44

#define strk_SIZE 0x28

#define GET_LIST_HEADER() \

    fourcc_tag = avio_rl32(pb); \

    size = avio_rl32(pb); \

    if (fourcc_tag != LIST_TAG) \

        return AVERROR_INVALIDDATA; \

    fourcc_tag = avio_rl32(pb);

typedef struct AudioTrack {

    int sample_rate;

    int bits;

    int channels;

    int stream_index;

    int adpcm;

    int64_t audio_pts;

} AudioTrack;

typedef struct FourxmDemuxContext {

    int width;

    int height;

    int video_stream_index;

    int track_count;

    AudioTrack *tracks;

    int64_t video_pts;

    float fps;

} FourxmDemuxContext;

static int fourxm_probe(AVProbeData *p)

{

    if ((AV_RL32(&p->buf[0]) != RIFF_TAG) ||

        (AV_RL32(&p->buf[8]) != FOURXMV_TAG))

        return 0;

    return AVPROBE_SCORE_MAX;

}

static int fourxm_read_header(AVFormatContext *s,

                              AVFormatParameters *ap)

{

    AVIOContext *pb = s->pb;

    unsigned int fourcc_tag;

    unsigned int size;

    int header_size;

    FourxmDemuxContext *fourxm = s->priv_data;

    unsigned char *header;

    int i, ret;

    AVStream *st;

    fourxm->track_count = 0;

    fourxm->tracks = NULL;

    fourxm->fps = 1.0;

    /* skip the first 3 32-bit numbers */

    avio_seek(pb, 12, SEEK_CUR);

    /* check for LIST-HEAD */

    GET_LIST_HEADER();

    header_size = size - 4;

    if (fourcc_tag != HEAD_TAG || header_size < 0)

        return AVERROR_INVALIDDATA;

    /* allocate space for the header and load the whole thing */

    header = av_malloc(header_size);

    if (!header)

        return AVERROR(ENOMEM);

    if (avio_read(pb, header, header_size) != header_size){

        av_free(header);

        return AVERROR(EIO);

    }

    /* take the lazy approach and search for any and all vtrk and strk chunks */

    for (i = 0; i < header_size - 8; i++) {

        fourcc_tag = AV_RL32(&header[i]);

        size = AV_RL32(&header[i + 4]);

        if (fourcc_tag == std__TAG) {

            fourxm->fps = av_int2flt(AV_RL32(&header[i + 12]));

        } else if (fourcc_tag == vtrk_TAG) {

            /* check that there is enough data */

            if (size != vtrk_SIZE) {

                ret= AVERROR_INVALIDDATA;

                goto fail;

            }

            fourxm->width  = AV_RL32(&header[i + 36]);

            fourxm->height = AV_RL32(&header[i + 40]);

            /* allocate a new AVStream */

            st = av_new_stream(s, 0);

            if (!st){

                ret= AVERROR(ENOMEM);

                goto fail;

            }

            av_set_pts_info(st, 60, 1, fourxm->fps);

            fourxm->video_stream_index = st->index;

            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

            st->codec->codec_id = CODEC_ID_4XM;

            st->codec->extradata_size = 4;

            st->codec->extradata = av_malloc(4);

            AV_WL32(st->codec->extradata, AV_RL32(&header[i + 16]));

            st->codec->width  = fourxm->width;

            st->codec->height = fourxm->height;

            i += 8 + size;

        } else if (fourcc_tag == strk_TAG) {

            int current_track;

            /* check that there is enough data */

            if (size != strk_SIZE) {

                ret= AVERROR_INVALIDDATA;

                goto fail;

            }

            current_track = AV_RL32(&header[i + 8]);

            if((unsigned)current_track >= UINT_MAX / sizeof(AudioTrack) - 1){

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

                ret= -1;

                goto fail;

            }

            if (current_track + 1 > fourxm->track_count) {

                fourxm->track_count = current_track + 1;

                fourxm->tracks = av_realloc(fourxm->tracks,

                    fourxm->track_count * sizeof(AudioTrack));

                if (!fourxm->tracks) {

                    ret=  AVERROR(ENOMEM);

                    goto fail;

                }

            }

            fourxm->tracks[current_track].adpcm       = AV_RL32(&header[i + 12]);

            fourxm->tracks[current_track].channels    = AV_RL32(&header[i + 36]);

            fourxm->tracks[current_track].sample_rate = AV_RL32(&header[i + 40]);

            fourxm->tracks[current_track].bits        = AV_RL32(&header[i + 44]);

            fourxm->tracks[current_track].audio_pts   = 0;

            if(   fourxm->tracks[current_track].channels    <= 0

               || fourxm->tracks[current_track].sample_rate <= 0

               || fourxm->tracks[current_track].bits        <  0){

                av_log(s, AV_LOG_ERROR, "audio header invalid\n");

                ret= -1;

                goto fail;

            }

            i += 8 + size;

            /* allocate a new AVStream */

            st = av_new_stream(s, current_track);

            if (!st){

                ret= AVERROR(ENOMEM);

                goto fail;

            }

            av_set_pts_info(st, 60, 1, fourxm->tracks[current_track].sample_rate);

            fourxm->tracks[current_track].stream_index = st->index;

            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

            st->codec->codec_tag = 0;

            st->codec->channels              = fourxm->tracks[current_track].channels;

            st->codec->sample_rate           = fourxm->tracks[current_track].sample_rate;

            st->codec->bits_per_coded_sample = fourxm->tracks[current_track].bits;

            st->codec->bit_rate              = st->codec->channels * st->codec->sample_rate *

                st->codec->bits_per_coded_sample;

            st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;

            if (fourxm->tracks[current_track].adpcm){

                st->codec->codec_id = CODEC_ID_ADPCM_4XM;

            }else if (st->codec->bits_per_coded_sample == 8){

                st->codec->codec_id = CODEC_ID_PCM_U8;

            }else

                st->codec->codec_id = CODEC_ID_PCM_S16LE;

        }

    }

    /* skip over the LIST-MOVI chunk (which is where the stream should be */

    GET_LIST_HEADER();

    if (fourcc_tag != MOVI_TAG){

        ret= AVERROR_INVALIDDATA;

        goto fail;

    }

    av_free(header);

    /* initialize context members */

    fourxm->video_pts = -1;  /* first frame will push to 0 */

    return 0;

fail:

    av_freep(&fourxm->tracks);

    av_free(header);

    return ret;

}

static int fourxm_read_packet(AVFormatContext *s,

                              AVPacket *pkt)

{

    FourxmDemuxContext *fourxm = s->priv_data;

    AVIOContext *pb = s->pb;

    unsigned int fourcc_tag;

    unsigned int size, out_size;

    int ret = 0;

    unsigned int track_number;

    int packet_read = 0;

    unsigned char header[8];

    int audio_frame_count;

    while (!packet_read) {

        if ((ret = avio_read(s->pb, header, 8)) < 0)

            return ret;

        fourcc_tag = AV_RL32(&header[0]);

        size = AV_RL32(&header[4]);

        if (url_feof(pb))

            return AVERROR(EIO);

        switch (fourcc_tag) {

        case LIST_TAG:

            /* this is a good time to bump the video pts */

            fourxm->video_pts ++;

            /* skip the LIST-* tag and move on to the next fourcc */

            avio_rl32(pb);

            break;

        case ifrm_TAG:

        case pfrm_TAG:

        case cfrm_TAG:

        case ifr2_TAG:

        case pfr2_TAG:

        case cfr2_TAG:

            /* allocate 8 more bytes than 'size' to account for fourcc

             * and size */

            if (size + 8 < size || av_new_packet(pkt, size + 8))

                return AVERROR(EIO);

            pkt->stream_index = fourxm->video_stream_index;

            pkt->pts = fourxm->video_pts;

            pkt->pos = avio_tell(s->pb);

            memcpy(pkt->data, header, 8);

            ret = avio_read(s->pb, &pkt->data[8], size);

            if (ret < 0){

                av_free_packet(pkt);

            }else

                packet_read = 1;

            break;

        case snd__TAG:

            track_number = avio_rl32(pb);

            out_size= avio_rl32(pb);

            size-=8;

            if (track_number < fourxm->track_count && fourxm->tracks[track_number].channels>0) {

                ret= av_get_packet(s->pb, pkt, size);

                if(ret<0)

                    return AVERROR(EIO);

                pkt->stream_index =

                    fourxm->tracks[track_number].stream_index;

                pkt->pts = fourxm->tracks[track_number].audio_pts;

                packet_read = 1;

                /* pts accounting */

                audio_frame_count = size;

                if (fourxm->tracks[track_number].adpcm)

                    audio_frame_count -=

                        2 * (fourxm->tracks[track_number].channels);

                audio_frame_count /=

                      fourxm->tracks[track_number].channels;

                if (fourxm->tracks[track_number].adpcm){

                    audio_frame_count *= 2;

                }else

                    audio_frame_count /=

                    (fourxm->tracks[track_number].bits / 8);

                fourxm->tracks[track_number].audio_pts += audio_frame_count;

            } else {

                avio_seek(pb, size, SEEK_CUR);

            }

            break;

        default:

            avio_seek(pb, size, SEEK_CUR);

            break;

        }

    }

    return ret;

}

static int fourxm_read_close(AVFormatContext *s)

{

    FourxmDemuxContext *fourxm = s->priv_data;

    av_freep(&fourxm->tracks);

    return 0;

}

AVInputFormat ff_fourxm_demuxer = {

    "4xm",

    NULL_IF_CONFIG_SMALL("4X Technologies format"),

    sizeof(FourxmDemuxContext),

    fourxm_probe,

    fourxm_read_header,

    fourxm_read_packet,

    fourxm_read_close,

};