libavcodec/libgsm.c

   1 /*
   2  * Interface to libgsm for gsm encoding/decoding
   3  * 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  * modify it under the terms of the GNU Lesser General Public
  10  * 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  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * 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  * Interface to libgsm for gsm encoding/decoding
  26  */
  27
  28 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
  29
  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 #define GSM_FRAME_SIZE 160
  37
  38 static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
  39     if (avctx->channels > 1) {
  40         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
  41                avctx->channels);
  42         return -1;
  43     }
  44
  45     if (avctx->sample_rate != 8000) {
  46         av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
  47                avctx->sample_rate);
  48         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
  49             return -1;
  50     }
  51     if (avctx->bit_rate != 13000 /* Official */ &&
  52         avctx->bit_rate != 13200 /* Very common */ &&
  53         avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
  54         av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
  55                avctx->bit_rate);
  56         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
  57             return -1;
  58     }
  59
  60     avctx->priv_data = gsm_create();
  61
  62     switch(avctx->codec_id) {
  63     case CODEC_ID_GSM:
  64         avctx->frame_size = GSM_FRAME_SIZE;
  65         avctx->block_align = GSM_BLOCK_SIZE;
  66         break;
  67     case CODEC_ID_GSM_MS: {
  68         int one = 1;
  69         gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
  70         avctx->frame_size = 2*GSM_FRAME_SIZE;
  71         avctx->block_align = GSM_MS_BLOCK_SIZE;
  72         }
  73     }
  74
  75     avctx->coded_frame= avcodec_alloc_frame();
  76     avctx->coded_frame->key_frame= 1;
  77
  78     return 0;
  79 }
  80
  81 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
  82     av_freep(&avctx->coded_frame);
  83     gsm_destroy(avctx->priv_data);
  84     avctx->priv_data = NULL;
  85     return 0;
  86 }
  87
  88 static int libgsm_encode_frame(AVCodecContext *avctx,
  89                                unsigned char *frame, int buf_size, void *data) {
  90     // we need a full block
  91     if(buf_size < avctx->block_align) return 0;
  92
  93     switch(avctx->codec_id) {
  94     case CODEC_ID_GSM:
  95         gsm_encode(avctx->priv_data,data,frame);
  96         break;
  97     case CODEC_ID_GSM_MS:
  98         gsm_encode(avctx->priv_data,data,frame);
  99         gsm_encode(avctx->priv_data,((short*)data)+GSM_FRAME_SIZE,frame+32);
 100     }
 101     return avctx->block_align;
 102 }
 103
 104
 105 AVCodec ff_libgsm_encoder = {
 106     .name           = "libgsm",
 107     .type           = AVMEDIA_TYPE_AUDIO,
 108     .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     .name           = "libgsm_ms",
 118     .type           = AVMEDIA_TYPE_AUDIO,
 119     .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 typedef struct LibGSMDecodeContext {
 128     AVFrame frame;
 129     struct gsm_state *state;
 130 } LibGSMDecodeContext;
 131
 132 static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
 133     LibGSMDecodeContext *s = avctx->priv_data;
 134
 135     if (avctx->channels > 1) {
 136         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
 137                avctx->channels);
 138         return -1;
 139     }
 140
 141     if (!avctx->channels)
 142         avctx->channels = 1;
 143
 144     if (!avctx->sample_rate)
 145         avctx->sample_rate = 8000;
 146
 147     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
 148
 149     s->state = gsm_create();
 150
 151     switch(avctx->codec_id) {
 152     case CODEC_ID_GSM:
 153         avctx->frame_size  = GSM_FRAME_SIZE;
 154         avctx->block_align = GSM_BLOCK_SIZE;
 155         break;
 156     case CODEC_ID_GSM_MS: {
 157         int one = 1;
 158         gsm_option(s->state, GSM_OPT_WAV49, &one);
 159         avctx->frame_size  = 2 * GSM_FRAME_SIZE;
 160         avctx->block_align = GSM_MS_BLOCK_SIZE;
 161         }
 162     }
 163
 164     avcodec_get_frame_defaults(&s->frame);
 165     avctx->coded_frame = &s->frame;
 166
 167     return 0;
 168 }
 169
 170 static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
 171     LibGSMDecodeContext *s = avctx->priv_data;
 172
 173     gsm_destroy(s->state);
 174     s->state = NULL;
 175     return 0;
 176 }
 177
 178 static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
 179                                int *got_frame_ptr, AVPacket *avpkt)
 180 {
 181     int i, ret;
 182     LibGSMDecodeContext *s = avctx->priv_data;
 183     uint8_t *buf = avpkt->data;
 184     int buf_size = avpkt->size;
 185     int16_t *samples;
 186
 187     if (buf_size < avctx->block_align) {
 188         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
 189         return AVERROR_INVALIDDATA;
 190     }
 191
 192     /* get output buffer */
 193     s->frame.nb_samples = avctx->frame_size;
 194     if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
 195         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 196         return ret;
 197     }
 198     samples = (int16_t *)s->frame.data[0];
 199
 200     for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
 201         if ((ret = gsm_decode(s->state, buf, samples)) < 0)
 202             return -1;
 203         buf     += GSM_BLOCK_SIZE;
 204         samples += GSM_FRAME_SIZE;
 205     }
 206
 207     *got_frame_ptr   = 1;
 208     *(AVFrame *)data = s->frame;
 209
 210     return avctx->block_align;
 211 }
 212
 213 static void libgsm_flush(AVCodecContext *avctx) {
 214     LibGSMDecodeContext *s = avctx->priv_data;
 215
 216     gsm_destroy(s->state);
 217     s->state = gsm_create();
 218 }
 219
 220 AVCodec ff_libgsm_decoder = {
 221     .name           = "libgsm",
 222     .type           = AVMEDIA_TYPE_AUDIO,
 223     .id             = CODEC_ID_GSM,
 224     .priv_data_size = sizeof(LibGSMDecodeContext),
 225     .init           = libgsm_decode_init,
 226     .close          = libgsm_decode_close,
 227     .decode         = libgsm_decode_frame,
 228     .flush          = libgsm_flush,
 229     .capabilities   = CODEC_CAP_DR1,
 230     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
 231 };
 232
 233 AVCodec ff_libgsm_ms_decoder = {
 234     .name           = "libgsm_ms",
 235     .type           = AVMEDIA_TYPE_AUDIO,
 236     .id             = CODEC_ID_GSM_MS,
 237     .priv_data_size = sizeof(LibGSMDecodeContext),
 238     .init           = libgsm_decode_init,
 239     .close          = libgsm_decode_close,
 240     .decode         = libgsm_decode_frame,
 241     .flush          = libgsm_flush,
 242     .capabilities   = CODEC_CAP_DR1,
 243     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
 244 };