libgsm: simplify decoding by using a loop
[libav.git] / 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 static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
128 if (avctx->channels > 1) {
129 av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
130 avctx->channels);
131 return -1;
132 }
133
134 if (!avctx->channels)
135 avctx->channels = 1;
136
137 if (!avctx->sample_rate)
138 avctx->sample_rate = 8000;
139
140 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
141
142 avctx->priv_data = gsm_create();
143
144 switch(avctx->codec_id) {
145 case CODEC_ID_GSM:
146 avctx->frame_size = GSM_FRAME_SIZE;
147 avctx->block_align = GSM_BLOCK_SIZE;
148 break;
149 case CODEC_ID_GSM_MS: {
150 int one = 1;
151 gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
152 avctx->frame_size = 2 * GSM_FRAME_SIZE;
153 avctx->block_align = GSM_MS_BLOCK_SIZE;
154 }
155 }
156
157 return 0;
158 }
159
160 static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
161 gsm_destroy(avctx->priv_data);
162 avctx->priv_data = NULL;
163 return 0;
164 }
165
166 static int libgsm_decode_frame(AVCodecContext *avctx,
167 void *data, int *data_size,
168 AVPacket *avpkt) {
169 int i, ret;
170 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 int out_size = avctx->frame_size * av_get_bytes_per_sample(avctx->sample_fmt);
175
176 if (*data_size < out_size) {
177 av_log(avctx, AV_LOG_ERROR, "Output buffer is too small\n");
178 return AVERROR(EINVAL);
179 }
180
181 if (buf_size < avctx->block_align) {
182 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
183 return AVERROR_INVALIDDATA;
184 }
185
186 for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
187 if ((ret = gsm_decode(s, buf, samples)) < 0)
188 return -1;
189 buf += GSM_BLOCK_SIZE;
190 samples += GSM_FRAME_SIZE;
191 }
192
193 *data_size = out_size;
194 return avctx->block_align;
195 }
196
197 AVCodec ff_libgsm_decoder = {
198 .name = "libgsm",
199 .type = AVMEDIA_TYPE_AUDIO,
200 .id = CODEC_ID_GSM,
201 .init = libgsm_decode_init,
202 .close = libgsm_decode_close,
203 .decode = libgsm_decode_frame,
204 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
205 };
206
207 AVCodec ff_libgsm_ms_decoder = {
208 .name = "libgsm_ms",
209 .type = AVMEDIA_TYPE_AUDIO,
210 .id = CODEC_ID_GSM_MS,
211 .init = libgsm_decode_init,
212 .close = libgsm_decode_close,
213 .decode = libgsm_decode_frame,
214 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
215 };