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ffmpeg / libavformat / flacenc.c @ 03700d39

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/*
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 * raw FLAC muxer
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 * Copyright (c) 2006-2009 Justin Ruggles
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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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#include "libavcodec/flac.h"
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#include "avformat.h"
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#include "flacenc.h"
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#include "metadata.h"
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#include "vorbiscomment.h"
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#include "libavcodec/bytestream.h"
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static int flac_write_block_padding(ByteIOContext *pb, unsigned int n_padding_bytes,
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                                    int last_block)
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{
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    put_byte(pb, last_block ? 0x81 : 0x01);
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    put_be24(pb, n_padding_bytes);
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    while (n_padding_bytes > 0) {
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        put_byte(pb, 0);
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        n_padding_bytes--;
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    }
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    return 0;
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}
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static int flac_write_block_comment(ByteIOContext *pb, AVMetadata **m,
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                                    int last_block, int bitexact)
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{
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    const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
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    unsigned int len, count;
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    uint8_t *p, *p0;
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    len = ff_vorbiscomment_length(*m, vendor, &count);
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    p0 = av_malloc(len+4);
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    if (!p0)
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        return AVERROR(ENOMEM);
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    p = p0;
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    bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
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    bytestream_put_be24(&p, len);
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    ff_vorbiscomment_write(&p, m, vendor, count);
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    put_buffer(pb, p0, len+4);
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    av_freep(&p0);
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    p = NULL;
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    return 0;
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}
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static int flac_write_header(struct AVFormatContext *s)
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{
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    int ret;
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    AVCodecContext *codec = s->streams[0]->codec;
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    ret = ff_flac_write_header(s->pb, codec, 0);
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    if (ret)
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        return ret;
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    ret = flac_write_block_comment(s->pb, &s->metadata, 0,
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                                   codec->flags & CODEC_FLAG_BITEXACT);
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    if (ret)
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        return ret;
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    /* The command line flac encoder defaults to placing a seekpoint
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     * every 10s.  So one might add padding to allow that later
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     * but there seems to be no simple way to get the duration here.
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     * So let's try the flac default of 8192 bytes */
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    flac_write_block_padding(s->pb, 8192, 1);
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    return ret;
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}
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static int flac_write_trailer(struct AVFormatContext *s)
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{
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    ByteIOContext *pb = s->pb;
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    uint8_t *streaminfo;
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    enum FLACExtradataFormat format;
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    int64_t file_size;
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    if (!ff_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
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        return -1;
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    if (!url_is_streamed(pb)) {
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        /* rewrite the STREAMINFO header block data */
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        file_size = url_ftell(pb);
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        url_fseek(pb, 8, SEEK_SET);
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        put_buffer(pb, streaminfo, FLAC_STREAMINFO_SIZE);
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        url_fseek(pb, file_size, SEEK_SET);
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        put_flush_packet(pb);
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    } else {
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        av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
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    }
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    return 0;
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}
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static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
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{
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    put_buffer(s->pb, pkt->data, pkt->size);
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    put_flush_packet(s->pb);
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    return 0;
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}
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AVOutputFormat flac_muxer = {
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    "flac",
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    NULL_IF_CONFIG_SMALL("raw FLAC"),
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    "audio/x-flac",
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    "flac",
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    0,
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    CODEC_ID_FLAC,
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    CODEC_ID_NONE,
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    flac_write_header,
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    flac_write_packet,
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    flac_write_trailer,
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    .flags= AVFMT_NOTIMESTAMPS,
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};