oggparseflac.c

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/*
 *    Copyright (C) 2005  Matthieu CASTET
 *
 * 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
 */
 
#include <stdlib.h>
#include "libavcodec/avcodec.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/flac.h"
#include "avformat.h"
#include "internal.h"
#include "oggdec.h"
 
#define OGG_FLAC_METADATA_TYPE_STREAMINFO 0x7F
#define OGG_FLAC_MAGIC "\177FLAC"
#define OGG_FLAC_MAGIC_SIZE sizeof(OGG_FLAC_MAGIC)-1
 
static int
flac_header (AVFormatContext * s, int idx)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + idx;
    AVStream *st = s->streams[idx];
    GetByteContext gb;
    int mdt, ret;
 
    if (os->buf[os->pstart] == 0xff)
        return 0;
 
    bytestream2_init(&gb, os->buf + os->pstart, os->psize);
    mdt = bytestream2_get_byte(&gb) & 0x7F;
 
    if (mdt == OGG_FLAC_METADATA_TYPE_STREAMINFO) {
        uint32_t samplerate;
 
        if (bytestream2_get_bytes_left(&gb) < 4 + 4 + 4 + 4 + FLAC_STREAMINFO_SIZE)
            return AVERROR_INVALIDDATA;
        bytestream2_skipu(&gb, 4); /* "FLAC" */
        if (bytestream2_get_byteu(&gb) != 1) /* unsupported major version */
            return -1;
        bytestream2_skipu(&gb, 1 + 2); /* minor version + header count */
        bytestream2_skipu(&gb, 4); /* "fLaC" */
 
        /* METADATA_BLOCK_HEADER */
        if (bytestream2_get_be32u(&gb) != FLAC_STREAMINFO_SIZE)
            return -1;
 
        st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
        st->codecpar->codec_id = AV_CODEC_ID_FLAC;
        ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS;
 
        if ((ret = ff_alloc_extradata(st->codecpar, FLAC_STREAMINFO_SIZE)) < 0)
            return ret;
        bytestream2_get_bufferu(&gb, st->codecpar->extradata, FLAC_STREAMINFO_SIZE);
 
        samplerate = AV_RB24(st->codecpar->extradata + 10) >> 4;
        if (!samplerate)
            return AVERROR_INVALIDDATA;
 
        avpriv_set_pts_info(st, 64, 1, samplerate);
    } else if (mdt == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
        ff_vorbis_stream_comment(s, st, os->buf + os->pstart + 4, os->psize - 4);
    }
 
    return 1;
}
 
static int
flac_packet (AVFormatContext * s, int idx)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + idx;
 
    if (os->psize > OGG_FLAC_MAGIC_SIZE &&
        !memcmp(
            os->buf + os->pstart,
            OGG_FLAC_MAGIC,
            OGG_FLAC_MAGIC_SIZE))
        return 1;
 
    if (os->psize > 0 &&
        ((os->buf[os->pstart] & 0x7F) == FLAC_METADATA_TYPE_VORBIS_COMMENT)) {
        return 1;
    }
 
    return 0;
}
 
static int
old_flac_header (AVFormatContext * s, int idx)
{
    struct ogg *ogg = s->priv_data;
    AVStream *st = s->streams[idx];
    struct ogg_stream *os = ogg->streams + idx;
    AVCodecParserContext *parser = av_parser_init(AV_CODEC_ID_FLAC);
    AVCodecContext *avctx;
    int size, ret;
    uint8_t *data;
 
    if (!parser)
        return -1;
 
    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
    st->codecpar->codec_id = AV_CODEC_ID_FLAC;
 
    avctx = avcodec_alloc_context3(NULL);
    if (!avctx) {
        ret = AVERROR(ENOMEM);
        goto fail;
    }
 
    ret = avcodec_parameters_to_context(avctx, st->codecpar);
    if (ret < 0)
        goto fail;
 
    parser->flags = PARSER_FLAG_COMPLETE_FRAMES;
    av_parser_parse2(parser, avctx,
                     &data, &size, os->buf + os->pstart, os->psize,
                     AV_NOPTS_VALUE, AV_NOPTS_VALUE, -1);
 
    av_parser_close(parser);
 
    if (avctx->sample_rate) {
        avpriv_set_pts_info(st, 64, 1, avctx->sample_rate);
        avcodec_free_context(&avctx);
        return 0;
    }
 
    avcodec_free_context(&avctx);
    return 1;
fail:
    av_parser_close(parser);
    avcodec_free_context(&avctx);
    return ret;
}
 
const struct ogg_codec ff_flac_codec = {
    .magic = OGG_FLAC_MAGIC,
    .magicsize = OGG_FLAC_MAGIC_SIZE,
    .header = flac_header,
    .nb_header = 2,
    .packet = flac_packet,
};
 
const struct ogg_codec ff_old_flac_codec = {
    .magic = "fLaC",
    .magicsize = 4,
    .header = old_flac_header,
    .nb_header = 0,
};