Statistics
| Branch: | Revision:

ffmpeg / libavcodec / libgsm.c @ bb4c2140

History | View | Annotate | Download (2.42 KB)

1
/*
2
 * Interface to libgsm for gsm encoding/decoding
3
 * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
4
 *
5
 * This library is free software; you can redistribute it and/or
6
 * modify it under the terms of the GNU Lesser General Public
7
 * License as published by the Free Software Foundation; either
8
 * version 2 of the License, or (at your option) any later version.
9
 *
10
 * This library 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 GNU
13
 * Lesser General Public License for more details.
14
 *
15
 * You should have received a copy of the GNU Lesser General Public
16
 * License along with this library; if not, write to the Free Software
17
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
 */
19
 
20
/**
21
 * @file libgsm.c
22
 * Interface to libgsm for gsm encoding/decoding
23
 */
24

    
25
#include "avcodec.h"
26
#include <gsm.h>
27

    
28
// gsm.h miss some essential constants
29
#define GSM_BLOCK_SIZE 33
30
#define GSM_FRAME_SIZE 160
31

    
32
static int libgsm_init(AVCodecContext *avctx) {
33
    if (avctx->channels > 1 || avctx->sample_rate != 8000)
34
        return -1;
35

    
36
    avctx->frame_size = GSM_FRAME_SIZE;
37
    avctx->block_align = GSM_BLOCK_SIZE;
38

    
39
    avctx->priv_data = gsm_create();
40
    
41
    avctx->coded_frame= avcodec_alloc_frame();
42
    avctx->coded_frame->key_frame= 1;
43
    
44
    return 0;
45
}
46

    
47
static int libgsm_close(AVCodecContext *avctx) {
48
    gsm_destroy(avctx->priv_data);
49
    avctx->priv_data = NULL;
50
    return 0;
51
}
52

    
53
static int libgsm_encode_frame(AVCodecContext *avctx,
54
                               unsigned char *frame, int buf_size, void *data) {
55
    // we need a full block
56
    if(buf_size < GSM_BLOCK_SIZE) return 0;
57

    
58
    gsm_encode(avctx->priv_data,data,frame);
59

    
60
    return GSM_BLOCK_SIZE;
61
}
62

    
63

    
64
AVCodec libgsm_encoder = {
65
    "gsm",
66
    CODEC_TYPE_AUDIO,
67
    CODEC_ID_GSM,
68
    0,
69
    libgsm_init,
70
    libgsm_encode_frame,
71
    libgsm_close,
72
};
73

    
74
static int libgsm_decode_frame(AVCodecContext *avctx,
75
                               void *data, int *data_size,
76
                               uint8_t *buf, int buf_size) {
77

    
78
    if(buf_size < GSM_BLOCK_SIZE) return 0;
79

    
80
    if(gsm_decode(avctx->priv_data,buf,data)) return -1;
81

    
82
    *data_size = GSM_FRAME_SIZE*2;
83
    return GSM_BLOCK_SIZE;
84
}
85

    
86
AVCodec libgsm_decoder = {
87
    "gsm",
88
    CODEC_TYPE_AUDIO,
89
    CODEC_ID_GSM,
90
    0,
91
    libgsm_init,
92
    NULL,
93
    libgsm_close,
94
    libgsm_decode_frame,
95
};