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ffmpeg / libavformat / oggparsetheora.c @ 01f4895c

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/**
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      Copyright (C) 2005  Matthieu CASTET
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      Permission is hereby granted, free of charge, to any person
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      obtaining a copy of this software and associated documentation
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      files (the "Software"), to deal in the Software without
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      restriction, including without limitation the rights to use, copy,
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      modify, merge, publish, distribute, sublicense, and/or sell copies
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      of the Software, and to permit persons to whom the Software is
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      furnished to do so, subject to the following conditions:
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      The above copyright notice and this permission notice shall be
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      included in all copies or substantial portions of the Software.
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      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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      EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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      MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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      NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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      HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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      WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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      OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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      DEALINGS IN THE SOFTWARE.
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**/
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#include <stdlib.h>
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#include "avformat.h"
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#include "bitstream.h"
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#include "bswap.h"
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#include "ogg2.h"
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typedef struct theora_params {
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    int gpshift;
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    int gpmask;
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} theora_params_t;
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static int
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theora_header (AVFormatContext * s, int idx)
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{
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    ogg_t *ogg = s->priv_data;
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    ogg_stream_t *os = ogg->streams + idx;
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    AVStream *st = s->streams[idx];
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    theora_params_t *thp = os->private;
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    int cds = st->codec->extradata_size + os->psize + 2;
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    uint8_t *cdp;
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    if(!(os->buf[os->pstart] & 0x80))
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        return 0;
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    if(!thp){
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        thp = av_mallocz(sizeof(*thp));
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        os->private = thp;
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    }
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    if (os->buf[os->pstart] == 0x80) {
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        GetBitContext gb;
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        init_get_bits(&gb, os->buf + os->pstart, os->psize*8);
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        skip_bits(&gb, 7*8); /* 0x80"theora" */
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        if(get_bits(&gb, 8) != 3) /* major version */
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            return -1;
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        if(get_bits(&gb, 8) != 2) /* minor version */
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            return -1;
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        skip_bits(&gb, 8);      /* revision */
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        st->codec->width = get_bits(&gb, 16) << 4;
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        st->codec->height = get_bits(&gb, 16) << 4;
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        skip_bits(&gb, 64);
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        st->codec->time_base.den = get_bits(&gb, 32);
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        st->codec->time_base.num = get_bits(&gb, 32);
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        st->codec->sample_aspect_ratio.num = get_bits(&gb, 24);
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        st->codec->sample_aspect_ratio.den = get_bits(&gb, 24);
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        skip_bits(&gb, 38);
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        thp->gpshift = get_bits(&gb, 5);
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        thp->gpmask = (1 << thp->gpshift) - 1;
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        st->codec->codec_type = CODEC_TYPE_VIDEO;
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        st->codec->codec_id = CODEC_ID_THEORA;
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    } else if (os->buf[os->pstart] == 0x83) {
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        vorbis_comment (s, os->buf + os->pstart + 7, os->psize - 8);
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    }
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    st->codec->extradata = av_realloc (st->codec->extradata, cds);
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    cdp = st->codec->extradata + st->codec->extradata_size;
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    *cdp++ = os->psize >> 8;
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    *cdp++ = os->psize & 0xff;
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    memcpy (cdp, os->buf + os->pstart, os->psize);
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    st->codec->extradata_size = cds;
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    return 1;
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}
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static uint64_t
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theora_gptopts(AVFormatContext *ctx, int idx, uint64_t gp)
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{
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    AVStream *st = ctx->streams[idx];
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    ogg_t *ogg = ctx->priv_data;
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    ogg_stream_t *os = ogg->streams + idx;
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    theora_params_t *thp = os->private;
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    uint64_t iframe = gp >> thp->gpshift;
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    uint64_t pframe = gp & thp->gpmask;
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    return (iframe + pframe) * AV_TIME_BASE * st->codec->time_base.num /
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        st->codec->time_base.den;
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}
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ogg_codec_t theora_codec = {
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    .magic = "\200theora",
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    .magicsize = 7,
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    .header = theora_header,
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    .gptopts = theora_gptopts
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};