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libavformat
flacenc.c
Go to the documentation of this file.
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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 Libav.
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*
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* Libav 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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* Libav 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 Libav; 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 "
vorbiscomment.h
"
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#include "
libavcodec/bytestream.h
"
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static
int
flac_write_block_padding
(
AVIOContext
*pb,
unsigned
int
n_padding_bytes,
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int
last_block)
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{
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avio_w8
(pb, last_block ? 0x81 : 0x01);
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avio_wb24
(pb, n_padding_bytes);
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while
(n_padding_bytes > 0) {
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avio_w8
(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
(
AVIOContext
*pb,
AVDictionary
**m,
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int
last_block,
int
bitexact)
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{
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const
char
*vendor = bitexact ?
"Libav"
:
LIBAVFORMAT_IDENT
;
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unsigned
int
len
, count;
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uint8_t *p, *p0;
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ff_metadata_conv
(m,
ff_vorbiscomment_metadata_conv
,
NULL
);
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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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avio_write
(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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AVIOContext
*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
(!
avpriv_flac_is_extradata_valid
(s->
streams
[0]->
codec
, &format, &streaminfo))
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return
-1;
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if
(pb->
seekable
) {
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/* rewrite the STREAMINFO header block data */
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file_size =
avio_tell
(pb);
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avio_seek
(pb, 8, SEEK_SET);
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avio_write
(pb, streaminfo,
FLAC_STREAMINFO_SIZE
);
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avio_seek
(pb, file_size, SEEK_SET);
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avio_flush
(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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avio_write
(s->
pb
, pkt->
data
, pkt->
size
);
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avio_flush
(s->
pb
);
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return
0;
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}
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AVOutputFormat
ff_flac_muxer
= {
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.
name
=
"flac"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"raw FLAC"
),
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.mime_type =
"audio/x-flac"
,
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.extensions =
"flac"
,
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.audio_codec =
CODEC_ID_FLAC
,
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.video_codec =
CODEC_ID_NONE
,
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.write_header =
flac_write_header
,
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.write_packet =
flac_write_packet
,
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.write_trailer =
flac_write_trailer
,
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.flags=
AVFMT_NOTIMESTAMPS
,
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};