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ffmpeg / libavformat / sol.c @ 5509bffa

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/*
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 * Sierra SOL decoder
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 * Copyright Konstantin Shishkov.
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 *
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 * This library 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 of the License, or (at your option) any later version.
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 *
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 * This library 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 this library; 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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 * Based on documents from Game Audio Player and own research
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 */
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#include "avformat.h"
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#include "avi.h"
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#include "bswap.h"
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/* if we don't know the size in advance */
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#define AU_UNKOWN_SIZE ((uint32_t)(~0))
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static int sol_probe(AVProbeData *p)
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{
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    /* check file header */
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    uint16_t magic;
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    if (p->buf_size <= 14)
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        return 0;
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    magic=le2me_16(*((uint16_t*)p->buf));
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    if ((magic == 0x0B8D || magic == 0x0C0D || magic == 0x0C8D) &&
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        p->buf[2] == 'S' && p->buf[3] == 'O' &&
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        p->buf[4] == 'L' && p->buf[5] == 0)
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        return AVPROBE_SCORE_MAX;
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    else
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        return 0;
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}
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#define SOL_DPCM    1
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#define SOL_16BIT   4
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#define SOL_STEREO 16
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static int sol_codec_id(int magic, int type)
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{
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    if (magic == 0x0B8D)
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    {
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        if (type & SOL_DPCM) return CODEC_ID_SOL_DPCM;
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        else return CODEC_ID_PCM_U8;
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    }
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    if (type & SOL_DPCM)
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    {
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        if (type & SOL_16BIT) return CODEC_ID_SOL_DPCM;
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        else if (magic == 0x0C8D) return CODEC_ID_SOL_DPCM;
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        else return CODEC_ID_SOL_DPCM;
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    }
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    if (type & SOL_16BIT) return CODEC_ID_PCM_S16LE;
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    return CODEC_ID_PCM_U8;
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}
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static int sol_codec_type(int magic, int type)
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{
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    if (magic == 0x0B8D) return 1;//SOL_DPCM_OLD;
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    if (type & SOL_DPCM)
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    {
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        if (type & SOL_16BIT) return 3;//SOL_DPCM_NEW16;
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        else if (magic == 0x0C8D) return 1;//SOL_DPCM_OLD;
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        else return 2;//SOL_DPCM_NEW8;
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    }
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    return -1;
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}
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static int sol_channels(int magic, int type)
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{
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    if (magic == 0x0B8D || !(type & SOL_STEREO)) return 1;
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    return 2;
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}
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static int sol_read_header(AVFormatContext *s,
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                          AVFormatParameters *ap)
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{
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    int size;
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    unsigned int magic,tag;
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    ByteIOContext *pb = &s->pb;
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    unsigned int id, codec, channels, rate, type;
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    AVStream *st;
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    /* check ".snd" header */
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    magic = get_le16(pb);
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    tag = get_le32(pb);
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    if (tag != MKTAG('S', 'O', 'L', 0))
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        return -1;
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    rate = get_le16(pb);
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    type = get_byte(pb);
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    size = get_le32(pb);
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    if (magic != 0x0B8D)
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        get_byte(pb); /* newer SOLs contain padding byte */
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    codec = sol_codec_id(magic, type);
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    channels = sol_channels(magic, type);
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    if (codec == CODEC_ID_SOL_DPCM)
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        id = sol_codec_type(magic, type);
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    else id = 0;
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    /* now we are ready: build format streams */
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    st = av_new_stream(s, 0);
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    if (!st)
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        return -1;
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    st->codec->codec_type = CODEC_TYPE_AUDIO;
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    st->codec->codec_tag = id;
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    st->codec->codec_id = codec;
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    st->codec->channels = channels;
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    st->codec->sample_rate = rate;
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    av_set_pts_info(st, 64, 1, rate);
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    return 0;
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}
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#define MAX_SIZE 4096
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static int sol_read_packet(AVFormatContext *s,
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                          AVPacket *pkt)
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{
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    int ret;
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    if (url_feof(&s->pb))
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        return -EIO;
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    ret= av_get_packet(&s->pb, pkt, MAX_SIZE);
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    pkt->stream_index = 0;
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    /* note: we need to modify the packet size here to handle the last
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       packet */
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    pkt->size = ret;
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    return 0;
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}
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static int sol_read_close(AVFormatContext *s)
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{
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    return 0;
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}
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static AVInputFormat sol_iformat = {
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    "sol",
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    "Sierra SOL Format",
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    0,
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    sol_probe,
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    sol_read_header,
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    sol_read_packet,
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    sol_read_close,
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    pcm_read_seek,
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};
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int sol_init(void)
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{
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    av_register_input_format(&sol_iformat);
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    return 0;
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}