summaryrefslogtreecommitdiffstats
path: root/libavcodec/libgsmdec.c
blob: a503215f679b0be08590e3f2e3c2caaad06ce52d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/*
 * Interface to libgsm for GSM decoding
 * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
 * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Interface to libgsm for GSM decoding
 */

// The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html

#include "config.h"
#if HAVE_GSM_H
#include <gsm.h>
#else
#include <gsm/gsm.h>
#endif

#include "libavutil/channel_layout.h"
#include "libavutil/common.h"

#include "avcodec.h"
#include "internal.h"
#include "gsm.h"

typedef struct LibGSMDecodeContext {
    struct gsm_state *state;
} LibGSMDecodeContext;

static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
    LibGSMDecodeContext *s = avctx->priv_data;

    avctx->channels       = 1;
    avctx->channel_layout = AV_CH_LAYOUT_MONO;
    if (!avctx->sample_rate)
        avctx->sample_rate = 8000;
    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;

    s->state = gsm_create();

    switch(avctx->codec_id) {
    case AV_CODEC_ID_GSM:
        avctx->frame_size  = GSM_FRAME_SIZE;
        avctx->block_align = GSM_BLOCK_SIZE;
        break;
    case AV_CODEC_ID_GSM_MS: {
        int one = 1;
        gsm_option(s->state, GSM_OPT_WAV49, &one);
        avctx->frame_size  = 2 * GSM_FRAME_SIZE;
        avctx->block_align = GSM_MS_BLOCK_SIZE;
        }
    }

    return 0;
}

static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
    LibGSMDecodeContext *s = avctx->priv_data;

    gsm_destroy(s->state);
    s->state = NULL;
    return 0;
}

static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
                               int *got_frame_ptr, AVPacket *avpkt)
{
    int i, ret;
    LibGSMDecodeContext *s = avctx->priv_data;
    AVFrame *frame         = data;
    uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    int16_t *samples;

    if (buf_size < avctx->block_align) {
        av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
        return AVERROR_INVALIDDATA;
    }

    /* get output buffer */
    frame->nb_samples = avctx->frame_size;
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
        return ret;
    samples = (int16_t *)frame->data[0];

    for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
        if ((ret = gsm_decode(s->state, buf, samples)) < 0)
            return -1;
        buf     += GSM_BLOCK_SIZE;
        samples += GSM_FRAME_SIZE;
    }

    *got_frame_ptr = 1;

    return avctx->block_align;
}

static void libgsm_flush(AVCodecContext *avctx) {
    LibGSMDecodeContext *s = avctx->priv_data;
    int one = 1;

    gsm_destroy(s->state);
    s->state = gsm_create();
    if (avctx->codec_id == AV_CODEC_ID_GSM_MS)
        gsm_option(s->state, GSM_OPT_WAV49, &one);
}

#if CONFIG_LIBGSM_DECODER
AVCodec ff_libgsm_decoder = {
    .name           = "libgsm",
    .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_GSM,
    .priv_data_size = sizeof(LibGSMDecodeContext),
    .init           = libgsm_decode_init,
    .close          = libgsm_decode_close,
    .decode         = libgsm_decode_frame,
    .flush          = libgsm_flush,
    .capabilities   = AV_CODEC_CAP_DR1,
};
#endif
#if CONFIG_LIBGSM_MS_DECODER
AVCodec ff_libgsm_ms_decoder = {
    .name           = "libgsm_ms",
    .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_GSM_MS,
    .priv_data_size = sizeof(LibGSMDecodeContext),
    .init           = libgsm_decode_init,
    .close          = libgsm_decode_close,
    .decode         = libgsm_decode_frame,
    .flush          = libgsm_flush,
    .capabilities   = AV_CODEC_CAP_DR1,
};
#endif
OpenPOWER on IntegriCloud