libgsm.c 6.89 KB
Newer Older
1 2 3
/*
 * Interface to libgsm for gsm encoding/decoding
 * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
4
 * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
5
 *
6
 * This file is part of Libav.
7
 *
8
 * Libav is free software; you can redistribute it and/or
9 10
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * Libav is distributed in the hope that it will be useful,
14 15 16 17 18
 * 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
19
 * License along with Libav; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22

23
/**
24
 * @file
25 26 27
 * Interface to libgsm for gsm encoding/decoding
 */

28 29
// The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html

30
#include "avcodec.h"
31
#include <gsm/gsm.h>
32

33
// gsm.h misses some essential constants
34
#define GSM_BLOCK_SIZE 33
35
#define GSM_MS_BLOCK_SIZE 65
36 37
#define GSM_FRAME_SIZE 160

38
static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
39 40 41
    if (avctx->channels > 1) {
        av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
               avctx->channels);
42
        return -1;
43
    }
Michael Niedermayer's avatar
Michael Niedermayer committed
44

45 46 47 48 49 50 51 52 53 54 55 56 57 58
    if (avctx->sample_rate != 8000) {
        av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
               avctx->sample_rate);
        if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
            return -1;
    }
    if (avctx->bit_rate != 13000 /* Official */ &&
        avctx->bit_rate != 13200 /* Very common */ &&
        avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
        av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
               avctx->bit_rate);
        if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
            return -1;
    }
59 60

    avctx->priv_data = gsm_create();
61

62 63 64 65 66 67 68 69 70 71 72 73 74
    switch(avctx->codec_id) {
    case CODEC_ID_GSM:
        avctx->frame_size = GSM_FRAME_SIZE;
        avctx->block_align = GSM_BLOCK_SIZE;
        break;
    case CODEC_ID_GSM_MS: {
        int one = 1;
        gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
        avctx->frame_size = 2*GSM_FRAME_SIZE;
        avctx->block_align = GSM_MS_BLOCK_SIZE;
        }
    }

75 76
    avctx->coded_frame= avcodec_alloc_frame();
    avctx->coded_frame->key_frame= 1;
77

78 79 80
    return 0;
}

81
static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
82
    av_freep(&avctx->coded_frame);
83 84 85 86 87 88 89 90
    gsm_destroy(avctx->priv_data);
    avctx->priv_data = NULL;
    return 0;
}

static int libgsm_encode_frame(AVCodecContext *avctx,
                               unsigned char *frame, int buf_size, void *data) {
    // we need a full block
91 92 93 94 95 96 97 98 99 100 101
    if(buf_size < avctx->block_align) return 0;

    switch(avctx->codec_id) {
    case CODEC_ID_GSM:
        gsm_encode(avctx->priv_data,data,frame);
        break;
    case CODEC_ID_GSM_MS:
        gsm_encode(avctx->priv_data,data,frame);
        gsm_encode(avctx->priv_data,((short*)data)+GSM_FRAME_SIZE,frame+32);
    }
    return avctx->block_align;
102 103 104
}


105
AVCodec ff_libgsm_encoder = {
106 107 108
    .name           = "libgsm",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_GSM,
109
    .init           = libgsm_encode_init,
110
    .encode         = libgsm_encode_frame,
111
    .close          = libgsm_encode_close,
112
    .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
113
    .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
114 115
};

116
AVCodec ff_libgsm_ms_encoder = {
117 118 119
    .name           = "libgsm_ms",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_GSM_MS,
120
    .init           = libgsm_encode_init,
121
    .encode         = libgsm_encode_frame,
122
    .close          = libgsm_encode_close,
123
    .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
124
    .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
125 126
};

127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
    if (avctx->channels > 1) {
        av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
               avctx->channels);
        return -1;
    }

    if (!avctx->channels)
        avctx->channels = 1;

    if (!avctx->sample_rate)
        avctx->sample_rate = 8000;

    avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    avctx->priv_data = gsm_create();

    switch(avctx->codec_id) {
    case CODEC_ID_GSM:
        avctx->frame_size  = GSM_FRAME_SIZE;
        avctx->block_align = GSM_BLOCK_SIZE;
        break;
    case CODEC_ID_GSM_MS: {
        int one = 1;
        gsm_option(avctx->priv_data, 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) {
    gsm_destroy(avctx->priv_data);
    avctx->priv_data = NULL;
    return 0;
}

166 167
static int libgsm_decode_frame(AVCodecContext *avctx,
                               void *data, int *data_size,
168
                               AVPacket *avpkt) {
169 170
    int i, ret;
    struct gsm_state *s = avctx->priv_data;
171
    uint8_t *buf = avpkt->data;
172
    int buf_size = avpkt->size;
173
    int16_t *samples = data;
174 175 176 177 178 179 180
    int out_size = avctx->frame_size * av_get_bytes_per_sample(avctx->sample_fmt);

    if (*data_size < out_size) {
        av_log(avctx, AV_LOG_ERROR, "Output buffer is too small\n");
        return AVERROR(EINVAL);
    }

181 182 183 184 185
    if (buf_size < avctx->block_align) {
        av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
        return AVERROR_INVALIDDATA;
    }

186 187 188 189 190
    for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
        if ((ret = gsm_decode(s, buf, samples)) < 0)
            return -1;
        buf     += GSM_BLOCK_SIZE;
        samples += GSM_FRAME_SIZE;
191
    }
192 193

    *data_size = out_size;
194
    return avctx->block_align;
195 196
}

197 198 199 200 201
static void libgsm_flush(AVCodecContext *avctx) {
    gsm_destroy(avctx->priv_data);
    avctx->priv_data = gsm_create();
}

202
AVCodec ff_libgsm_decoder = {
203 204 205
    .name           = "libgsm",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_GSM,
206 207
    .init           = libgsm_decode_init,
    .close          = libgsm_decode_close,
208
    .decode         = libgsm_decode_frame,
209
    .flush          = libgsm_flush,
210
    .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
211
};
212

213
AVCodec ff_libgsm_ms_decoder = {
214 215 216
    .name           = "libgsm_ms",
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = CODEC_ID_GSM_MS,
217 218
    .init           = libgsm_decode_init,
    .close          = libgsm_decode_close,
219
    .decode         = libgsm_decode_frame,
220
    .flush          = libgsm_flush,
221
    .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
222
};