PeerStreamer

/*

 * Westwood Studios Multimedia Formats Demuxer (VQA, AUD)

 * Copyright (c) 2003 The ffmpeg Project

 *

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

 *

 * This library 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 this library; if not, write to the Free Software

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

 */

/**

 * @file westwood.c

 * Westwood Studios VQA & AUD file demuxers

 * by Mike Melanson (melanson@pcisys.net)

 * for more information on the Westwood file formats, visit:

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

 *   http://www.geocities.com/SiliconValley/8682/aud3.txt

 *

 * Implementation note: There is no definite file signature for AUD files.

 * The demuxer uses a probabilistic strategy for content detection. This

 * entails performing sanity checks on certain header values in order to

 * qualify a file. Refer to wsaud_probe() for the precise parameters.

 */

#include "avformat.h"

#define AUD_HEADER_SIZE 12

#define AUD_CHUNK_PREAMBLE_SIZE 8

#define AUD_CHUNK_SIGNATURE 0x0000DEAF

#define FORM_TAG MKBETAG('F', 'O', 'R', 'M')

#define WVQA_TAG MKBETAG('W', 'V', 'Q', 'A')

#define VQHD_TAG MKBETAG('V', 'Q', 'H', 'D')

#define FINF_TAG MKBETAG('F', 'I', 'N', 'F')

#define SND0_TAG MKBETAG('S', 'N', 'D', '0')

#define SND2_TAG MKBETAG('S', 'N', 'D', '2')

#define VQFR_TAG MKBETAG('V', 'Q', 'F', 'R')

/* don't know what these tags are for, but acknowledge their existence */

#define CINF_TAG MKBETAG('C', 'I', 'N', 'F')

#define CINH_TAG MKBETAG('C', 'I', 'N', 'H')

#define CIND_TAG MKBETAG('C', 'I', 'N', 'D')

#define PINF_TAG MKBETAG('P', 'I', 'N', 'F')

#define PINH_TAG MKBETAG('P', 'I', 'N', 'H')

#define PIND_TAG MKBETAG('P', 'I', 'N', 'D')

#define VQA_HEADER_SIZE 0x2A

#define VQA_FRAMERATE 15

#define VQA_VIDEO_PTS_INC (90000 / VQA_FRAMERATE)

#define VQA_PREAMBLE_SIZE 8

typedef struct WsAudDemuxContext {

    int audio_samplerate;

    int audio_channels;

    int audio_bits;

    int audio_type;

    int audio_stream_index;

    int64_t audio_frame_counter;

} WsAudDemuxContext;

typedef struct WsVqaDemuxContext {

    int audio_samplerate;

    int audio_channels;

    int audio_bits;

    int audio_stream_index;

    int video_stream_index;

    int64_t audio_frame_counter;

    int64_t video_pts;

} WsVqaDemuxContext;

static int wsaud_probe(AVProbeData *p)

{

    int field;

    /* Probabilistic content detection strategy: There is no file signature

     * so perform sanity checks on various header parameters:

     *   8000 <= sample rate (16 bits) <= 48000  ==> 40001 acceptable numbers

     *   compression type (8 bits) = 1 or 99     ==> 2 acceptable numbers

     * There is a total of 24 bits. The number space contains 2^24 =

     * 16777216 numbers. There are 40001 * 2 = 80002 acceptable combinations

     * of numbers. There is a 80002/16777216 = 0.48% chance of a false

     * positive.

     */

    if (p->buf_size < AUD_HEADER_SIZE)

        return 0;

    /* check sample rate */

    field = LE_16(&p->buf[0]);

    if ((field < 8000) || (field > 48000))

        return 0;

    /* note: only check for WS IMA (type 99) right now since there is no

     * support for type 1 */

    if (p->buf[11] != 99)

        return 0;

    /* return 1/2 certainty since this file check is a little sketchy */

    return AVPROBE_SCORE_MAX / 2;

}

static int wsaud_read_header(AVFormatContext *s,

                             AVFormatParameters *ap)

{

    WsAudDemuxContext *wsaud = (WsAudDemuxContext *)s->priv_data;

    ByteIOContext *pb = &s->pb;

    AVStream *st;

    unsigned char header[AUD_HEADER_SIZE];

    if (get_buffer(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)

        return AVERROR_IO;

    wsaud->audio_samplerate = LE_16(&header[0]);

    if (header[11] == 99)

        wsaud->audio_type = CODEC_ID_ADPCM_IMA_WS;

    else

        return AVERROR_INVALIDDATA;

    /* flag 0 indicates stereo */

    wsaud->audio_channels = (header[10] & 0x1) + 1;

    /* flag 1 indicates 16 bit audio */

    wsaud->audio_bits = (((header[10] & 0x2) >> 1) + 1) * 8;

    /* initialize the audio decoder stream */

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR_NOMEM;

    av_set_pts_info(st, 33, 1, wsaud->audio_samplerate);

    st->codec->codec_type = CODEC_TYPE_AUDIO;

    st->codec->codec_id = wsaud->audio_type;

    st->codec->codec_tag = 0;  /* no tag */

    st->codec->channels = wsaud->audio_channels;

    st->codec->sample_rate = wsaud->audio_samplerate;

    st->codec->bits_per_sample = wsaud->audio_bits;

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

        st->codec->bits_per_sample / 4;

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

    wsaud->audio_stream_index = st->index;

    wsaud->audio_frame_counter = 0;

    return 0;

}

static int wsaud_read_packet(AVFormatContext *s,

                             AVPacket *pkt)

{

    WsAudDemuxContext *wsaud = (WsAudDemuxContext *)s->priv_data;

    ByteIOContext *pb = &s->pb;

    unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE];

    unsigned int chunk_size;

    int ret = 0;

    if (get_buffer(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=

        AUD_CHUNK_PREAMBLE_SIZE)

        return AVERROR_IO;

    /* validate the chunk */

    if (LE_32(&preamble[4]) != AUD_CHUNK_SIGNATURE)

        return AVERROR_INVALIDDATA;

    chunk_size = LE_16(&preamble[0]);

    ret= av_get_packet(pb, pkt, chunk_size);

    if (ret != chunk_size)

        return AVERROR_IO;

    pkt->stream_index = wsaud->audio_stream_index;

    pkt->pts = wsaud->audio_frame_counter;

    pkt->pts /= wsaud->audio_samplerate;

    /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */

    wsaud->audio_frame_counter += (chunk_size * 2) / wsaud->audio_channels;

    return ret;

}

static int wsaud_read_close(AVFormatContext *s)

{

//    WsAudDemuxContext *wsaud = (WsAudDemuxContext *)s->priv_data;

    return 0;

}

static int wsvqa_probe(AVProbeData *p)

{

    /* need 12 bytes to qualify */

    if (p->buf_size < 12)

        return 0;

    /* check for the VQA signatures */

    if ((BE_32(&p->buf[0]) != FORM_TAG) ||

        (BE_32(&p->buf[8]) != WVQA_TAG))

        return 0;

    return AVPROBE_SCORE_MAX;

}

static int wsvqa_read_header(AVFormatContext *s,

                             AVFormatParameters *ap)

{

    WsVqaDemuxContext *wsvqa = (WsVqaDemuxContext *)s->priv_data;

    ByteIOContext *pb = &s->pb;

    AVStream *st;

    unsigned char *header;

    unsigned char scratch[VQA_PREAMBLE_SIZE];

    unsigned int chunk_tag;

    unsigned int chunk_size;

    /* initialize the video decoder stream */

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR_NOMEM;

    av_set_pts_info(st, 33, 1, 90000);

    wsvqa->video_stream_index = st->index;

    st->codec->codec_type = CODEC_TYPE_VIDEO;

    st->codec->codec_id = CODEC_ID_WS_VQA;

    st->codec->codec_tag = 0;  /* no fourcc */

    /* skip to the start of the VQA header */

    url_fseek(pb, 20, SEEK_SET);

    /* the VQA header needs to go to the decoder */

    st->codec->extradata_size = VQA_HEADER_SIZE;

    st->codec->extradata = av_mallocz(VQA_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);

    header = (unsigned char *)st->codec->extradata;

    if (get_buffer(pb, st->codec->extradata, VQA_HEADER_SIZE) !=

        VQA_HEADER_SIZE) {

        av_free(st->codec->extradata);

        return AVERROR_IO;

    }

    st->codec->width = LE_16(&header[6]);

    st->codec->height = LE_16(&header[8]);

    /* initialize the audio decoder stream is sample rate is non-zero */

    if (LE_16(&header[24])) {

        st = av_new_stream(s, 0);

        if (!st)

            return AVERROR_NOMEM;

        av_set_pts_info(st, 33, 1, 90000);

        st->codec->codec_type = CODEC_TYPE_AUDIO;

        st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;

        st->codec->codec_tag = 0;  /* no tag */

        st->codec->sample_rate = LE_16(&header[24]);

        st->codec->channels = header[26];

        st->codec->bits_per_sample = 16;

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

            st->codec->bits_per_sample / 4;

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

        wsvqa->audio_stream_index = st->index;

        wsvqa->audio_samplerate = st->codec->sample_rate;

        wsvqa->audio_channels = st->codec->channels;

        wsvqa->audio_frame_counter = 0;

    }

    /* there are 0 or more chunks before the FINF chunk; iterate until

     * FINF has been skipped and the file will be ready to be demuxed */

    do {

        if (get_buffer(pb, scratch, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE) {

            av_free(st->codec->extradata);

            return AVERROR_IO;

        }

        chunk_tag = BE_32(&scratch[0]);

        chunk_size = BE_32(&scratch[4]);

        /* catch any unknown header tags, for curiousity */

        switch (chunk_tag) {

        case CINF_TAG:

        case CINH_TAG:

        case CIND_TAG:

        case PINF_TAG:

        case PINH_TAG:

        case PIND_TAG:

        case FINF_TAG:

            break;

        default:

            av_log (s, AV_LOG_ERROR, " note: unknown chunk seen (%c%c%c%c)\n",

                scratch[0], scratch[1],

                scratch[2], scratch[3]);

            break;

        }

        url_fseek(pb, chunk_size, SEEK_CUR);

    } while (chunk_tag != FINF_TAG);

    wsvqa->video_pts = wsvqa->audio_frame_counter = 0;

    return 0;

}

static int wsvqa_read_packet(AVFormatContext *s,

                             AVPacket *pkt)

{

    WsVqaDemuxContext *wsvqa = (WsVqaDemuxContext *)s->priv_data;

    ByteIOContext *pb = &s->pb;

    int ret = 0;

    unsigned char preamble[VQA_PREAMBLE_SIZE];

    unsigned int chunk_type;

    unsigned int chunk_size;

    int skip_byte;

    if (get_buffer(pb, preamble, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE)

        return AVERROR_IO;

    chunk_type = BE_32(&preamble[0]);

    chunk_size = BE_32(&preamble[4]);

    skip_byte = chunk_size & 0x01;

    if ((chunk_type == SND2_TAG) || (chunk_type == VQFR_TAG)) {

        av_get_packet(pb, pkt, chunk_size);

        if (ret != chunk_size) {

            ret = AVERROR_IO;

        }

        if (chunk_type == SND2_TAG) {

            pkt->stream_index = wsvqa->audio_stream_index;

            pkt->pts = 90000;

            pkt->pts *= wsvqa->audio_frame_counter;

            pkt->pts /= wsvqa->audio_samplerate;

            /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */

            wsvqa->audio_frame_counter += (chunk_size * 2) /

                wsvqa->audio_channels;

        } else {

            pkt->stream_index = wsvqa->video_stream_index;

            pkt->pts = wsvqa->video_pts;

            wsvqa->video_pts += VQA_VIDEO_PTS_INC;

        }

    } else

        return AVERROR_INVALIDDATA;

    /* stay on 16-bit alignment */

    if (skip_byte)

        url_fseek(pb, 1, SEEK_CUR);

    return ret;

}

static int wsvqa_read_close(AVFormatContext *s)

{

//    WsVqaDemuxContext *wsvqa = (WsVqaDemuxContext *)s->priv_data;

    return 0;

}

static AVInputFormat wsaud_iformat = {

    "wsaud",

    "Westwood Studios audio format",

    sizeof(WsAudDemuxContext),

    wsaud_probe,

    wsaud_read_header,

    wsaud_read_packet,

    wsaud_read_close,

};

static AVInputFormat wsvqa_iformat = {

    "wsvqa",

    "Westwood Studios VQA format",

    sizeof(WsVqaDemuxContext),

    wsvqa_probe,

    wsvqa_read_header,

    wsvqa_read_packet,

    wsvqa_read_close,

};

int westwood_init(void)

{

    av_register_input_format(&wsaud_iformat);

    av_register_input_format(&wsvqa_iformat);

    return 0;

}