FFmpeg/libavformat/westwood_vqa.c

/*
 * Westwood Studios VQA Format Demuxer
 * 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
 * Westwood Studios VQA file demuxer
 * 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
 */

#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"

#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 SND1_TAG MKBETAG('S', 'N', 'D', '1')
#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 CMDS_TAG MKBETAG('C', 'M', 'D', 'S')

#define VQA_HEADER_SIZE 0x2A
#define VQA_FRAMERATE 15
#define VQA_PREAMBLE_SIZE 8

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;
} WsVqaDemuxContext;

static int wsvqa_probe(AVProbeData *p)
{
    /* need 12 bytes to qualify */
    if (p->buf_size < 12)
        return 0;

    /* check for the VQA signatures */
    if ((AV_RB32(&p->buf[0]) != FORM_TAG) ||
        (AV_RB32(&p->buf[8]) != WVQA_TAG))
        return 0;

    return AVPROBE_SCORE_MAX;
}

static int wsvqa_read_header(AVFormatContext *s,
                             AVFormatParameters *ap)
{
    WsVqaDemuxContext *wsvqa = s->priv_data;
    AVIOContext *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 = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);
    avpriv_set_pts_info(st, 33, 1, VQA_FRAMERATE);
    wsvqa->video_stream_index = st->index;
    st->codec->codec_type = AVMEDIA_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 */
    avio_seek(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 (avio_read(pb, st->codec->extradata, VQA_HEADER_SIZE) !=
        VQA_HEADER_SIZE) {
        av_free(st->codec->extradata);
        return AVERROR(EIO);
    }
    st->codec->width = AV_RL16(&header[6]);
    st->codec->height = AV_RL16(&header[8]);

    /* initialize the audio decoder stream for VQA v1 or nonzero samplerate */
    if (AV_RL16(&header[24]) || (AV_RL16(&header[0]) == 1 && AV_RL16(&header[2]) == 1)) {
        st = avformat_new_stream(s, NULL);
        if (!st)
            return AVERROR(ENOMEM);
        avpriv_set_pts_info(st, 33, 1, VQA_FRAMERATE);
        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        if (AV_RL16(&header[0]) == 1)
            st->codec->codec_id = CODEC_ID_WESTWOOD_SND1;
        else
            st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;
        st->codec->codec_tag = 0;  /* no tag */
        st->codec->sample_rate = AV_RL16(&header[24]);
        if (!st->codec->sample_rate)
            st->codec->sample_rate = 22050;
        st->codec->channels = header[26];
        if (!st->codec->channels)
            st->codec->channels = 1;
        st->codec->bits_per_coded_sample = 16;
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
            st->codec->bits_per_coded_sample / 4;
        st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_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 (avio_read(pb, scratch, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE)
            return AVERROR(EIO);
        chunk_tag = AV_RB32(&scratch[0]);
        chunk_size = AV_RB32(&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:
        case CMDS_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;
        }

        avio_skip(pb, chunk_size);
    } while (chunk_tag != FINF_TAG);

    return 0;
}

static int wsvqa_read_packet(AVFormatContext *s,
                             AVPacket *pkt)
{
    WsVqaDemuxContext *wsvqa = s->priv_data;
    AVIOContext *pb = s->pb;
    int ret = -1;
    unsigned char preamble[VQA_PREAMBLE_SIZE];
    unsigned int chunk_type;
    unsigned int chunk_size;
    int skip_byte;

    while (avio_read(pb, preamble, VQA_PREAMBLE_SIZE) == VQA_PREAMBLE_SIZE) {
        chunk_type = AV_RB32(&preamble[0]);
        chunk_size = AV_RB32(&preamble[4]);

        skip_byte = chunk_size & 0x01;

        if ((chunk_type == SND2_TAG || chunk_type == SND1_TAG) && wsvqa->audio_channels == 0) {
            av_log(s, AV_LOG_ERROR, "audio chunk without any audio header information found\n");
            return AVERROR_INVALIDDATA;
        }

        if ((chunk_type == SND1_TAG) || (chunk_type == SND2_TAG) || (chunk_type == VQFR_TAG)) {

            ret= av_get_packet(pb, pkt, chunk_size);
            if (ret<0)
                return AVERROR(EIO);

            if (chunk_type == SND2_TAG) {
                pkt->stream_index = wsvqa->audio_stream_index;
                /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
                wsvqa->audio_frame_counter += (chunk_size * 2) / wsvqa->audio_channels;
            } else if(chunk_type == SND1_TAG) {
                pkt->stream_index = wsvqa->audio_stream_index;
                /* unpacked size is stored in header */
                wsvqa->audio_frame_counter += AV_RL16(pkt->data) / wsvqa->audio_channels;
            } else {
                pkt->stream_index = wsvqa->video_stream_index;
            }
            /* stay on 16-bit alignment */
            if (skip_byte)
                avio_skip(pb, 1);

            return ret;
        } else {
            switch(chunk_type){
            case CMDS_TAG:
            case SND0_TAG:
                break;
            default:
                av_log(s, AV_LOG_INFO, "Skipping unknown chunk 0x%08X\n", chunk_type);
            }
            avio_skip(pb, chunk_size + skip_byte);
        }
    }

    return ret;
}

AVInputFormat ff_wsvqa_demuxer = {
    .name           = "wsvqa",
    .long_name      = NULL_IF_CONFIG_SMALL("Westwood Studios VQA format"),
    .priv_data_size = sizeof(WsVqaDemuxContext),
    .read_probe     = wsvqa_probe,
    .read_header    = wsvqa_read_header,
    .read_packet    = wsvqa_read_packet,
};