- Added MP3 encoding through libmp3lame contributed by Lennert Buytenhek.
[libav.git] / libavcodec / mp3lameaudio.c
CommitLineData
0716b577
J
1/*
2 * Interface to libmp3lame for mp3 encoding
3 * Copyright (c) 2002 Lennert Buytenhek <buytenh@gnu.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19
20#include "avcodec.h"
21#include <math.h>
22#include "mpegaudio.h"
23#include <lame/lame.h>
24
25typedef struct Mp3AudioContext {
26 lame_global_flags *gfp;
27 int first_frame;
28 int stereo;
29} Mp3AudioContext;
30
31
32static int MP3lame_encode_init(AVCodecContext *avctx)
33{
34 Mp3AudioContext *s = avctx->priv_data;
35
36 if (avctx->channels > 2)
37 return -1;
38
39 s->first_frame = 1;
40 s->stereo = avctx->channels > 1 ? 1 : 0;
41
42 if ((s->gfp = lame_init()) == NULL)
43 goto err;
44 lame_set_in_samplerate(s->gfp, avctx->sample_rate);
45 lame_set_num_channels(s->gfp, avctx->channels);
46 /* lame 3.91 dies on quality != 5 */
47 lame_set_quality(s->gfp, 5);
48 /* lame 3.91 doesn't work in mono */
49 lame_set_mode(s->gfp, JOINT_STEREO);
50 lame_set_brate(s->gfp, avctx->bit_rate/1000);
51 if (lame_init_params(s->gfp) < 0)
52 goto err_close;
53
54 avctx->frame_size = MPA_FRAME_SIZE;
55 avctx->key_frame = 1;
56
57 return 0;
58
59err_close:
60 lame_close(s->gfp);
61err:
62 return -1;
63}
64
65int MP3lame_encode_frame(AVCodecContext *avctx,
66 unsigned char *frame, int buf_size, void *data)
67{
68 Mp3AudioContext *s = avctx->priv_data;
69 int num;
70
71 /* lame 3.91 dies on '1-channel interleaved' data */
72 if (s->stereo) {
73 num = lame_encode_buffer_interleaved(s->gfp, data,
74 MPA_FRAME_SIZE, frame, buf_size);
75 } else {
76 num = lame_encode_buffer(s->gfp, data, data, MPA_FRAME_SIZE,
77 frame, buf_size);
78 }
79
80 /* lame 3.91 outputs the first frame as garbage */
81 if (s->first_frame)
82 s->first_frame = num = 0;
83
84 return num;
85}
86
87int MP3lame_encode_close(AVCodecContext *avctx)
88{
89 Mp3AudioContext *s = avctx->priv_data;
90
91 lame_close(s->gfp);
92 return 0;
93}
94
95
96AVCodec mp3lame_encoder = {
97 "mp3",
98 CODEC_TYPE_AUDIO,
99 CODEC_ID_MP3LAME,
100 sizeof(Mp3AudioContext),
101 MP3lame_encode_init,
102 MP3lame_encode_frame,
103 MP3lame_encode_close
104};