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FFmpeg/libavformat/flacenc.c
Clément Bœsch 7308439158 lavf: Don't explicitly flush after each written packet in muxers
Since 596e5d4783, this is not necessary anymore. It also allows to
actually disable the flushing, improving write performance (but
possibly giving worse latency in real-time streaming).

Signed-off-by: Martin Storsjö <martin@martin.st>
2013-09-16 22:17:33 +03:00

131 lines
3.8 KiB
C

/*
* raw FLAC muxer
* Copyright (c) 2006-2009 Justin Ruggles
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavcodec/flac.h"
#include "avformat.h"
#include "flacenc.h"
#include "vorbiscomment.h"
#include "libavcodec/bytestream.h"
static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
int last_block)
{
avio_w8(pb, last_block ? 0x81 : 0x01);
avio_wb24(pb, n_padding_bytes);
while (n_padding_bytes > 0) {
avio_w8(pb, 0);
n_padding_bytes--;
}
return 0;
}
static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
int last_block, int bitexact)
{
const char *vendor = bitexact ? "Libav" : LIBAVFORMAT_IDENT;
unsigned int len, count;
uint8_t *p, *p0;
ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
len = ff_vorbiscomment_length(*m, vendor, &count);
p0 = av_malloc(len+4);
if (!p0)
return AVERROR(ENOMEM);
p = p0;
bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
bytestream_put_be24(&p, len);
ff_vorbiscomment_write(&p, m, vendor, count);
avio_write(pb, p0, len+4);
av_freep(&p0);
p = NULL;
return 0;
}
static int flac_write_header(struct AVFormatContext *s)
{
int ret;
AVCodecContext *codec = s->streams[0]->codec;
ret = ff_flac_write_header(s->pb, codec, 0);
if (ret)
return ret;
ret = flac_write_block_comment(s->pb, &s->metadata, 0,
codec->flags & CODEC_FLAG_BITEXACT);
if (ret)
return ret;
/* The command line flac encoder defaults to placing a seekpoint
* every 10s. So one might add padding to allow that later
* but there seems to be no simple way to get the duration here.
* So let's try the flac default of 8192 bytes */
flac_write_block_padding(s->pb, 8192, 1);
return ret;
}
static int flac_write_trailer(struct AVFormatContext *s)
{
AVIOContext *pb = s->pb;
uint8_t *streaminfo;
enum FLACExtradataFormat format;
int64_t file_size;
if (!avpriv_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
return -1;
if (pb->seekable) {
/* rewrite the STREAMINFO header block data */
file_size = avio_tell(pb);
avio_seek(pb, 8, SEEK_SET);
avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
avio_seek(pb, file_size, SEEK_SET);
avio_flush(pb);
} else {
av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
}
return 0;
}
static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
{
avio_write(s->pb, pkt->data, pkt->size);
return 0;
}
AVOutputFormat ff_flac_muxer = {
.name = "flac",
.long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
.mime_type = "audio/x-flac",
.extensions = "flac",
.audio_codec = AV_CODEC_ID_FLAC,
.video_codec = AV_CODEC_ID_NONE,
.write_header = flac_write_header,
.write_packet = flac_write_packet,
.write_trailer = flac_write_trailer,
.flags = AVFMT_NOTIMESTAMPS,
};