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>
6 * This file is part of Libav.
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.
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.
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
25 * Interface to libgsm for gsm encoding/decoding
28 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
37 #include "libavutil/channel_layout.h"
38 #include "libavutil/common.h"
43 static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
44 if (avctx->channels > 1) {
45 av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
50 if (avctx->sample_rate != 8000) {
51 av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
53 if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
56 if (avctx->bit_rate != 13000 /* Official */ &&
57 avctx->bit_rate != 13200 /* Very common */ &&
58 avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
59 av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
61 if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
65 avctx->priv_data = gsm_create();
67 switch(avctx->codec_id) {
69 avctx->frame_size = GSM_FRAME_SIZE;
70 avctx->block_align = GSM_BLOCK_SIZE;
72 case AV_CODEC_ID_GSM_MS: {
74 gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
75 avctx->frame_size = 2*GSM_FRAME_SIZE;
76 avctx->block_align = GSM_MS_BLOCK_SIZE;
83 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
84 gsm_destroy(avctx->priv_data);
85 avctx->priv_data = NULL;
89 static int libgsm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
90 const AVFrame *frame, int *got_packet_ptr)
93 gsm_signal *samples = (gsm_signal *)frame->data[0];
94 struct gsm_state *state = avctx->priv_data;
96 if ((ret = ff_alloc_packet(avpkt, avctx->block_align))) {
97 av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
101 switch(avctx->codec_id) {
102 case AV_CODEC_ID_GSM:
103 gsm_encode(state, samples, avpkt->data);
105 case AV_CODEC_ID_GSM_MS:
106 gsm_encode(state, samples, avpkt->data);
107 gsm_encode(state, samples + GSM_FRAME_SIZE, avpkt->data + 32);
115 AVCodec ff_libgsm_encoder = {
117 .type = AVMEDIA_TYPE_AUDIO,
118 .id = AV_CODEC_ID_GSM,
119 .init = libgsm_encode_init,
120 .encode2 = libgsm_encode_frame,
121 .close = libgsm_encode_close,
122 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
123 AV_SAMPLE_FMT_NONE },
124 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
127 AVCodec ff_libgsm_ms_encoder = {
129 .type = AVMEDIA_TYPE_AUDIO,
130 .id = AV_CODEC_ID_GSM_MS,
131 .init = libgsm_encode_init,
132 .encode2 = libgsm_encode_frame,
133 .close = libgsm_encode_close,
134 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
135 AV_SAMPLE_FMT_NONE },
136 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
139 typedef struct LibGSMDecodeContext {
140 struct gsm_state *state;
141 } LibGSMDecodeContext;
143 static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
144 LibGSMDecodeContext *s = avctx->priv_data;
147 avctx->channel_layout = AV_CH_LAYOUT_MONO;
148 avctx->sample_rate = 8000;
149 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
151 s->state = gsm_create();
153 switch(avctx->codec_id) {
154 case AV_CODEC_ID_GSM:
155 avctx->frame_size = GSM_FRAME_SIZE;
156 avctx->block_align = GSM_BLOCK_SIZE;
158 case AV_CODEC_ID_GSM_MS: {
160 gsm_option(s->state, GSM_OPT_WAV49, &one);
161 avctx->frame_size = 2 * GSM_FRAME_SIZE;
162 avctx->block_align = GSM_MS_BLOCK_SIZE;
169 static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
170 LibGSMDecodeContext *s = avctx->priv_data;
172 gsm_destroy(s->state);
177 static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
178 int *got_frame_ptr, AVPacket *avpkt)
181 LibGSMDecodeContext *s = avctx->priv_data;
182 AVFrame *frame = data;
183 uint8_t *buf = avpkt->data;
184 int buf_size = avpkt->size;
187 if (buf_size < avctx->block_align) {
188 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
189 return AVERROR_INVALIDDATA;
192 /* get output buffer */
193 frame->nb_samples = avctx->frame_size;
194 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
195 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
198 samples = (int16_t *)frame->data[0];
200 for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
201 if ((ret = gsm_decode(s->state, buf, samples)) < 0)
203 buf += GSM_BLOCK_SIZE;
204 samples += GSM_FRAME_SIZE;
209 return avctx->block_align;
212 static void libgsm_flush(AVCodecContext *avctx) {
213 LibGSMDecodeContext *s = avctx->priv_data;
216 gsm_destroy(s->state);
217 s->state = gsm_create();
218 if (avctx->codec_id == AV_CODEC_ID_GSM_MS)
219 gsm_option(s->state, GSM_OPT_WAV49, &one);
222 AVCodec ff_libgsm_decoder = {
224 .type = AVMEDIA_TYPE_AUDIO,
225 .id = AV_CODEC_ID_GSM,
226 .priv_data_size = sizeof(LibGSMDecodeContext),
227 .init = libgsm_decode_init,
228 .close = libgsm_decode_close,
229 .decode = libgsm_decode_frame,
230 .flush = libgsm_flush,
231 .capabilities = CODEC_CAP_DR1,
232 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
235 AVCodec ff_libgsm_ms_decoder = {
237 .type = AVMEDIA_TYPE_AUDIO,
238 .id = AV_CODEC_ID_GSM_MS,
239 .priv_data_size = sizeof(LibGSMDecodeContext),
240 .init = libgsm_decode_init,
241 .close = libgsm_decode_close,
242 .decode = libgsm_decode_frame,
243 .flush = libgsm_flush,
244 .capabilities = CODEC_CAP_DR1,
245 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),