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 FFmpeg.
7 *
8 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 "config.h"
31#if HAVE_GSM_H
32#include <gsm.h>
33#else
34#include <gsm/gsm.h>
35#endif
36
37#include "libavutil/channel_layout.h"
38#include "libavutil/common.h"
39#include "avcodec.h"
40#include "internal.h"
41#include "gsm.h"
42
43static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
44    gsm_destroy(avctx->priv_data);
45    avctx->priv_data = NULL;
46    return 0;
47}
48
49static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
50    if (avctx->channels > 1) {
51        av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
52               avctx->channels);
53        return -1;
54    }
55
56    if (avctx->sample_rate != 8000) {
57        av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
58               avctx->sample_rate);
59        if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
60            return -1;
61    }
62    if (avctx->bit_rate != 13000 /* Official */ &&
63        avctx->bit_rate != 13200 /* Very common */ &&
64        avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
65        av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
66               avctx->bit_rate);
67        if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
68            return -1;
69    }
70
71    avctx->priv_data = gsm_create();
72    if (!avctx->priv_data)
73        goto error;
74
75    switch(avctx->codec_id) {
76    case AV_CODEC_ID_GSM:
77        avctx->frame_size = GSM_FRAME_SIZE;
78        avctx->block_align = GSM_BLOCK_SIZE;
79        break;
80    case AV_CODEC_ID_GSM_MS: {
81        int one = 1;
82        gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
83        avctx->frame_size = 2*GSM_FRAME_SIZE;
84        avctx->block_align = GSM_MS_BLOCK_SIZE;
85        }
86    }
87
88    return 0;
89error:
90    libgsm_encode_close(avctx);
91    return -1;
92}
93
94static int libgsm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
95                               const AVFrame *frame, int *got_packet_ptr)
96{
97    int ret;
98    gsm_signal *samples = (gsm_signal *)frame->data[0];
99    struct gsm_state *state = avctx->priv_data;
100
101    if ((ret = ff_alloc_packet2(avctx, avpkt, avctx->block_align)) < 0)
102        return ret;
103
104    switch(avctx->codec_id) {
105    case AV_CODEC_ID_GSM:
106        gsm_encode(state, samples, avpkt->data);
107        break;
108    case AV_CODEC_ID_GSM_MS:
109        gsm_encode(state, samples,                  avpkt->data);
110        gsm_encode(state, samples + GSM_FRAME_SIZE, avpkt->data + 32);
111    }
112
113    *got_packet_ptr = 1;
114    return 0;
115}
116
117
118#if CONFIG_LIBGSM_ENCODER
119AVCodec ff_libgsm_encoder = {
120    .name           = "libgsm",
121    .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM"),
122    .type           = AVMEDIA_TYPE_AUDIO,
123    .id             = AV_CODEC_ID_GSM,
124    .init           = libgsm_encode_init,
125    .encode2        = libgsm_encode_frame,
126    .close          = libgsm_encode_close,
127    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
128                                                     AV_SAMPLE_FMT_NONE },
129};
130#endif
131#if CONFIG_LIBGSM_MS_ENCODER
132AVCodec ff_libgsm_ms_encoder = {
133    .name           = "libgsm_ms",
134    .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
135    .type           = AVMEDIA_TYPE_AUDIO,
136    .id             = AV_CODEC_ID_GSM_MS,
137    .init           = libgsm_encode_init,
138    .encode2        = libgsm_encode_frame,
139    .close          = libgsm_encode_close,
140    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
141                                                     AV_SAMPLE_FMT_NONE },
142};
143#endif
144
145typedef struct LibGSMDecodeContext {
146    struct gsm_state *state;
147} LibGSMDecodeContext;
148
149static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
150    LibGSMDecodeContext *s = avctx->priv_data;
151
152    avctx->channels       = 1;
153    avctx->channel_layout = AV_CH_LAYOUT_MONO;
154    if (!avctx->sample_rate)
155        avctx->sample_rate = 8000;
156    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;
157
158    s->state = gsm_create();
159
160    switch(avctx->codec_id) {
161    case AV_CODEC_ID_GSM:
162        avctx->frame_size  = GSM_FRAME_SIZE;
163        avctx->block_align = GSM_BLOCK_SIZE;
164        break;
165    case AV_CODEC_ID_GSM_MS: {
166        int one = 1;
167        gsm_option(s->state, GSM_OPT_WAV49, &one);
168        avctx->frame_size  = 2 * GSM_FRAME_SIZE;
169        avctx->block_align = GSM_MS_BLOCK_SIZE;
170        }
171    }
172
173    return 0;
174}
175
176static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
177    LibGSMDecodeContext *s = avctx->priv_data;
178
179    gsm_destroy(s->state);
180    s->state = NULL;
181    return 0;
182}
183
184static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
185                               int *got_frame_ptr, AVPacket *avpkt)
186{
187    int i, ret;
188    LibGSMDecodeContext *s = avctx->priv_data;
189    AVFrame *frame         = data;
190    uint8_t *buf = avpkt->data;
191    int buf_size = avpkt->size;
192    int16_t *samples;
193
194    if (buf_size < avctx->block_align) {
195        av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
196        return AVERROR_INVALIDDATA;
197    }
198
199    /* get output buffer */
200    frame->nb_samples = avctx->frame_size;
201    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
202        return ret;
203    samples = (int16_t *)frame->data[0];
204
205    for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
206        if ((ret = gsm_decode(s->state, buf, samples)) < 0)
207            return -1;
208        buf     += GSM_BLOCK_SIZE;
209        samples += GSM_FRAME_SIZE;
210    }
211
212    *got_frame_ptr = 1;
213
214    return avctx->block_align;
215}
216
217static void libgsm_flush(AVCodecContext *avctx) {
218    LibGSMDecodeContext *s = avctx->priv_data;
219    int one = 1;
220
221    gsm_destroy(s->state);
222    s->state = gsm_create();
223    if (avctx->codec_id == AV_CODEC_ID_GSM_MS)
224        gsm_option(s->state, GSM_OPT_WAV49, &one);
225}
226
227#if CONFIG_LIBGSM_DECODER
228AVCodec ff_libgsm_decoder = {
229    .name           = "libgsm",
230    .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM"),
231    .type           = AVMEDIA_TYPE_AUDIO,
232    .id             = AV_CODEC_ID_GSM,
233    .priv_data_size = sizeof(LibGSMDecodeContext),
234    .init           = libgsm_decode_init,
235    .close          = libgsm_decode_close,
236    .decode         = libgsm_decode_frame,
237    .flush          = libgsm_flush,
238    .capabilities   = CODEC_CAP_DR1,
239};
240#endif
241#if CONFIG_LIBGSM_MS_DECODER
242AVCodec ff_libgsm_ms_decoder = {
243    .name           = "libgsm_ms",
244    .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
245    .type           = AVMEDIA_TYPE_AUDIO,
246    .id             = AV_CODEC_ID_GSM_MS,
247    .priv_data_size = sizeof(LibGSMDecodeContext),
248    .init           = libgsm_decode_init,
249    .close          = libgsm_decode_close,
250    .decode         = libgsm_decode_frame,
251    .flush          = libgsm_flush,
252    .capabilities   = CODEC_CAP_DR1,
253};
254#endif
255