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/*
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 * Westwood Studios Multimedia Formats Demuxer (VQA, AUD)
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 * Copyright (c) 2003 The ffmpeg Project
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file westwood.c
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 * Westwood Studios VQA & AUD file demuxers
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 * by Mike Melanson (melanson@pcisys.net)
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 * for more information on the Westwood file formats, visit:
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 *   http://www.pcisys.net/~melanson/codecs/
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 *   http://www.geocities.com/SiliconValley/8682/aud3.txt
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 *
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 * Implementation note: There is no definite file signature for AUD files.
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 * The demuxer uses a probabilistic strategy for content detection. This
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 * entails performing sanity checks on certain header values in order to
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 * qualify a file. Refer to wsaud_probe() for the precise parameters.
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 */
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#include "avformat.h"
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#define AUD_HEADER_SIZE 12
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#define AUD_CHUNK_PREAMBLE_SIZE 8
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#define AUD_CHUNK_SIGNATURE 0x0000DEAF
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#define FORM_TAG MKBETAG('F', 'O', 'R', 'M')
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#define WVQA_TAG MKBETAG('W', 'V', 'Q', 'A')
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#define VQHD_TAG MKBETAG('V', 'Q', 'H', 'D')
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#define FINF_TAG MKBETAG('F', 'I', 'N', 'F')
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#define SND0_TAG MKBETAG('S', 'N', 'D', '0')
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#define SND1_TAG MKBETAG('S', 'N', 'D', '1')
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#define SND2_TAG MKBETAG('S', 'N', 'D', '2')
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#define VQFR_TAG MKBETAG('V', 'Q', 'F', 'R')
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/* don't know what these tags are for, but acknowledge their existence */
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#define CINF_TAG MKBETAG('C', 'I', 'N', 'F')
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#define CINH_TAG MKBETAG('C', 'I', 'N', 'H')
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#define CIND_TAG MKBETAG('C', 'I', 'N', 'D')
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#define PINF_TAG MKBETAG('P', 'I', 'N', 'F')
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#define PINH_TAG MKBETAG('P', 'I', 'N', 'H')
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#define PIND_TAG MKBETAG('P', 'I', 'N', 'D')
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#define CMDS_TAG MKBETAG('C', 'M', 'D', 'S')
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#define VQA_HEADER_SIZE 0x2A
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#define VQA_FRAMERATE 15
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#define VQA_VIDEO_PTS_INC (90000 / VQA_FRAMERATE)
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#define VQA_PREAMBLE_SIZE 8
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typedef struct WsAudDemuxContext {
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    int audio_samplerate;
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    int audio_channels;
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    int audio_bits;
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    int audio_type;
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    int audio_stream_index;
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    int64_t audio_frame_counter;
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} WsAudDemuxContext;
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typedef struct WsVqaDemuxContext {
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    int audio_samplerate;
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    int audio_channels;
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    int audio_bits;
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    int audio_stream_index;
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    int video_stream_index;
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    int64_t audio_frame_counter;
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    int64_t video_pts;
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} WsVqaDemuxContext;
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static int wsaud_probe(AVProbeData *p)
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{
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    int field;
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    /* Probabilistic content detection strategy: There is no file signature
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     * so perform sanity checks on various header parameters:
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     *   8000 <= sample rate (16 bits) <= 48000  ==> 40001 acceptable numbers
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     *   flags <= 0x03 (2 LSBs are used)         ==> 4 acceptable numbers
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     *   compression type (8 bits) = 1 or 99     ==> 2 acceptable numbers
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     *   first audio chunk signature (32 bits)   ==> 1 acceptable number
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     * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 =
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     * 320008 acceptable number combinations.
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     */
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    if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE)
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        return 0;
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    /* check sample rate */
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    field = AV_RL16(&p->buf[0]);
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    if ((field < 8000) || (field > 48000))
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        return 0;
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    /* enforce the rule that the top 6 bits of this flags field are reserved (0);
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     * this might not be true, but enforce it until deemed unnecessary */
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    if (p->buf[10] & 0xFC)
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        return 0;
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    /* note: only check for WS IMA (type 99) right now since there is no
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     * support for type 1 */
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    if (p->buf[11] != 99)
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        return 0;
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    /* read ahead to the first audio chunk and validate the first header signature */
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    if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE)
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        return 0;
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    /* return 1/2 certainty since this file check is a little sketchy */
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    return AVPROBE_SCORE_MAX / 2;
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}
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static int wsaud_read_header(AVFormatContext *s,
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                             AVFormatParameters *ap)
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{
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    WsAudDemuxContext *wsaud = s->priv_data;
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    ByteIOContext *pb = s->pb;
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    AVStream *st;
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    unsigned char header[AUD_HEADER_SIZE];
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    if (get_buffer(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)
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        return AVERROR(EIO);
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    wsaud->audio_samplerate = AV_RL16(&header[0]);
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    if (header[11] == 99)
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        wsaud->audio_type = CODEC_ID_ADPCM_IMA_WS;
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    else
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        return AVERROR_INVALIDDATA;
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    /* flag 0 indicates stereo */
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    wsaud->audio_channels = (header[10] & 0x1) + 1;
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    /* flag 1 indicates 16 bit audio */
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    wsaud->audio_bits = (((header[10] & 0x2) >> 1) + 1) * 8;
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    /* initialize the audio decoder stream */
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    st = av_new_stream(s, 0);
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    if (!st)
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        return AVERROR(ENOMEM);
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    av_set_pts_info(st, 33, 1, wsaud->audio_samplerate);
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    st->codec->codec_type = CODEC_TYPE_AUDIO;
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    st->codec->codec_id = wsaud->audio_type;
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    st->codec->codec_tag = 0;  /* no tag */
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    st->codec->channels = wsaud->audio_channels;
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    st->codec->sample_rate = wsaud->audio_samplerate;
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    st->codec->bits_per_sample = wsaud->audio_bits;
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    st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
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        st->codec->bits_per_sample / 4;
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    st->codec->block_align = st->codec->channels * st->codec->bits_per_sample;
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    wsaud->audio_stream_index = st->index;
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    wsaud->audio_frame_counter = 0;
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    return 0;
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}
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static int wsaud_read_packet(AVFormatContext *s,
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                             AVPacket *pkt)
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{
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    WsAudDemuxContext *wsaud = s->priv_data;
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    ByteIOContext *pb = s->pb;
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    unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE];
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    unsigned int chunk_size;
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    int ret = 0;
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    if (get_buffer(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=
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        AUD_CHUNK_PREAMBLE_SIZE)
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        return AVERROR(EIO);
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    /* validate the chunk */
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    if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE)
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        return AVERROR_INVALIDDATA;
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    chunk_size = AV_RL16(&preamble[0]);
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    ret= av_get_packet(pb, pkt, chunk_size);
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    if (ret != chunk_size)
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        return AVERROR(EIO);
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    pkt->stream_index = wsaud->audio_stream_index;
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    pkt->pts = wsaud->audio_frame_counter;
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    pkt->pts /= wsaud->audio_samplerate;
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    /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
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    wsaud->audio_frame_counter += (chunk_size * 2) / wsaud->audio_channels;
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    return ret;
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}
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static int wsvqa_probe(AVProbeData *p)
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{
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    /* need 12 bytes to qualify */
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    if (p->buf_size < 12)
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        return 0;
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    /* check for the VQA signatures */
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    if ((AV_RB32(&p->buf[0]) != FORM_TAG) ||
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        (AV_RB32(&p->buf[8]) != WVQA_TAG))
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        return 0;
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    return AVPROBE_SCORE_MAX;
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}
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static int wsvqa_read_header(AVFormatContext *s,
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                             AVFormatParameters *ap)
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{
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    WsVqaDemuxContext *wsvqa = s->priv_data;
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    ByteIOContext *pb = s->pb;
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    AVStream *st;
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    unsigned char *header;
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    unsigned char scratch[VQA_PREAMBLE_SIZE];
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    unsigned int chunk_tag;
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    unsigned int chunk_size;
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    /* initialize the video decoder stream */
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    st = av_new_stream(s, 0);
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    if (!st)
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        return AVERROR(ENOMEM);
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    av_set_pts_info(st, 33, 1, VQA_FRAMERATE);
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    wsvqa->video_stream_index = st->index;
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    st->codec->codec_type = CODEC_TYPE_VIDEO;
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    st->codec->codec_id = CODEC_ID_WS_VQA;
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    st->codec->codec_tag = 0;  /* no fourcc */
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    /* skip to the start of the VQA header */
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    url_fseek(pb, 20, SEEK_SET);
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    /* the VQA header needs to go to the decoder */
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    st->codec->extradata_size = VQA_HEADER_SIZE;
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    st->codec->extradata = av_mallocz(VQA_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
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    header = (unsigned char *)st->codec->extradata;
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    if (get_buffer(pb, st->codec->extradata, VQA_HEADER_SIZE) !=
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        VQA_HEADER_SIZE) {
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        av_free(st->codec->extradata);
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        return AVERROR(EIO);
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    }
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    st->codec->width = AV_RL16(&header[6]);
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    st->codec->height = AV_RL16(&header[8]);
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    /* initialize the audio decoder stream for VQA v1 or nonzero samplerate */
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    if (AV_RL16(&header[24]) || (AV_RL16(&header[0]) == 1 && AV_RL16(&header[2]) == 1)) {
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        st = av_new_stream(s, 0);
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        if (!st)
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            return AVERROR(ENOMEM);
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        av_set_pts_info(st, 33, 1, VQA_FRAMERATE);
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        st->codec->codec_type = CODEC_TYPE_AUDIO;
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        if (AV_RL16(&header[0]) == 1)
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            st->codec->codec_id = CODEC_ID_WESTWOOD_SND1;
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        else
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            st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;
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        st->codec->codec_tag = 0;  /* no tag */
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        st->codec->sample_rate = AV_RL16(&header[24]);
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        if (!st->codec->sample_rate)
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            st->codec->sample_rate = 22050;
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        st->codec->channels = header[26];
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        if (!st->codec->channels)
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            st->codec->channels = 1;
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        st->codec->bits_per_sample = 16;
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        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
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            st->codec->bits_per_sample / 4;
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        st->codec->block_align = st->codec->channels * st->codec->bits_per_sample;
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        wsvqa->audio_stream_index = st->index;
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        wsvqa->audio_samplerate = st->codec->sample_rate;
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        wsvqa->audio_channels = st->codec->channels;
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        wsvqa->audio_frame_counter = 0;
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    }
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    /* there are 0 or more chunks before the FINF chunk; iterate until
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     * FINF has been skipped and the file will be ready to be demuxed */
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    do {
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        if (get_buffer(pb, scratch, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE) {
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            av_free(st->codec->extradata);
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            return AVERROR(EIO);
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        }
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        chunk_tag = AV_RB32(&scratch[0]);
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        chunk_size = AV_RB32(&scratch[4]);
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        /* catch any unknown header tags, for curiousity */
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        switch (chunk_tag) {
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        case CINF_TAG:
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        case CINH_TAG:
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        case CIND_TAG:
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        case PINF_TAG:
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        case PINH_TAG:
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        case PIND_TAG:
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        case FINF_TAG:
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        case CMDS_TAG:
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            break;
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        default:
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            av_log (s, AV_LOG_ERROR, " note: unknown chunk seen (%c%c%c%c)\n",
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                scratch[0], scratch[1],
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                scratch[2], scratch[3]);
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            break;
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        }
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        url_fseek(pb, chunk_size, SEEK_CUR);
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    } while (chunk_tag != FINF_TAG);
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    wsvqa->video_pts = wsvqa->audio_frame_counter = 0;
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    return 0;
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}
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static int wsvqa_read_packet(AVFormatContext *s,
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                             AVPacket *pkt)
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{
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    WsVqaDemuxContext *wsvqa = s->priv_data;
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    ByteIOContext *pb = s->pb;
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    int ret = -1;
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    unsigned char preamble[VQA_PREAMBLE_SIZE];
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    unsigned int chunk_type;
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    unsigned int chunk_size;
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    int skip_byte;
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    while (get_buffer(pb, preamble, VQA_PREAMBLE_SIZE) == VQA_PREAMBLE_SIZE) {
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        chunk_type = AV_RB32(&preamble[0]);
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        chunk_size = AV_RB32(&preamble[4]);
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        skip_byte = chunk_size & 0x01;
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        if ((chunk_type == SND1_TAG) || (chunk_type == SND2_TAG) || (chunk_type == VQFR_TAG)) {
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            if (av_new_packet(pkt, chunk_size))
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                return AVERROR(EIO);
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            ret = get_buffer(pb, pkt->data, chunk_size);
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            if (ret != chunk_size) {
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                av_free_packet(pkt);
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                return AVERROR(EIO);
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            }
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            if (chunk_type == SND2_TAG) {
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                pkt->stream_index = wsvqa->audio_stream_index;
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                /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
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                wsvqa->audio_frame_counter += (chunk_size * 2) / wsvqa->audio_channels;
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            } else if(chunk_type == SND1_TAG) {
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                pkt->stream_index = wsvqa->audio_stream_index;
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                /* unpacked size is stored in header */
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                wsvqa->audio_frame_counter += AV_RL16(pkt->data) / wsvqa->audio_channels;
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            } else {
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                pkt->stream_index = wsvqa->video_stream_index;
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                wsvqa->video_pts += VQA_VIDEO_PTS_INC;
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            }
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            /* stay on 16-bit alignment */
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            if (skip_byte)
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                url_fseek(pb, 1, SEEK_CUR);
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            return ret;
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        } else {
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            switch(chunk_type){
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            case CMDS_TAG:
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            case SND0_TAG:
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                break;
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            default:
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                av_log(s, AV_LOG_INFO, "Skipping unknown chunk 0x%08X\n", chunk_type);
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            }
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            url_fseek(pb, chunk_size + skip_byte, SEEK_CUR);
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        }
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    }
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    return ret;
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}
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#ifdef CONFIG_WSAUD_DEMUXER
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AVInputFormat wsaud_demuxer = {
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    "wsaud",
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    NULL_IF_CONFIG_SMALL("Westwood Studios audio format"),
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    sizeof(WsAudDemuxContext),
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    wsaud_probe,
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    wsaud_read_header,
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    wsaud_read_packet,
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};
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#endif
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#ifdef CONFIG_WSVQA_DEMUXER
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AVInputFormat wsvqa_demuxer = {
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    "wsvqa",
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    NULL_IF_CONFIG_SMALL("Westwood Studios VQA format"),
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    sizeof(WsVqaDemuxContext),
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    wsvqa_probe,
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    wsvqa_read_header,
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    wsvqa_read_packet,
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};
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#endif