cosmetics: add a comment in flac_write_header().
[libav.git] / libavformat / flacenc.c
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1/*
2 * raw FLAC muxer
3 * Copyright (c) 2006-2009 Justin Ruggles
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
59c6178a 22#include "libavcodec/flac.h"
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23#include "avformat.h"
24
25static int flac_write_header(struct AVFormatContext *s)
26{
27 static const uint8_t header[8] = {
28 0x66, 0x4C, 0x61, 0x43, 0x80, 0x00, 0x00, 0x22
29 };
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30 AVCodecContext *codec = s->streams[0]->codec;
31 uint8_t *streaminfo;
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32 enum FLACExtradataFormat format;
33
34 if (!ff_flac_is_extradata_valid(codec, &format, &streaminfo))
35 return -1;
36
faec0eba 37 /* write "fLaC" stream marker and first metadata block header if needed */
59c6178a 38 if (format == FLAC_EXTRADATA_FORMAT_STREAMINFO) {
caee91f7 39 put_buffer(s->pb, header, 8);
caee91f7 40 }
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41
42 /* write STREAMINFO or full header */
43 put_buffer(s->pb, codec->extradata, codec->extradata_size);
44
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45 return 0;
46}
47
48static int flac_write_trailer(struct AVFormatContext *s)
49{
50 ByteIOContext *pb = s->pb;
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51 uint8_t *streaminfo;
52 enum FLACExtradataFormat format;
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53 int64_t file_size;
54
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55 if (!ff_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
56 return -1;
57
58 if (!url_is_streamed(pb)) {
59 /* rewrite the STREAMINFO header block data */
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60 file_size = url_ftell(pb);
61 url_fseek(pb, 8, SEEK_SET);
59c6178a 62 put_buffer(pb, streaminfo, FLAC_STREAMINFO_SIZE);
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63 url_fseek(pb, file_size, SEEK_SET);
64 put_flush_packet(pb);
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65 } else {
66 av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
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67 }
68 return 0;
69}
70
71static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
72{
73 put_buffer(s->pb, pkt->data, pkt->size);
74 put_flush_packet(s->pb);
75 return 0;
76}
77
78AVOutputFormat flac_muxer = {
79 "flac",
80 NULL_IF_CONFIG_SMALL("raw FLAC"),
81 "audio/x-flac",
82 "flac",
83 0,
84 CODEC_ID_FLAC,
85 CODEC_ID_NONE,
86 flac_write_header,
87 flac_write_packet,
88 flac_write_trailer,
89 .flags= AVFMT_NOTIMESTAMPS,
90};