1 /*
2 * Interface to libgsm for GSM encoding
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
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/common.h"
38
39 #include "avcodec.h"
40 #include "internal.h"
41 #include "gsm.h"
42
libgsm_encode_close(AVCodecContext * avctx)43 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
44 gsm_destroy(avctx->priv_data);
45 avctx->priv_data = NULL;
46 return 0;
47 }
48
libgsm_encode_init(AVCodecContext * avctx)49 static 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 %"PRId64"bps\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;
89 error:
90 libgsm_encode_close(avctx);
91 return -1;
92 }
93
libgsm_encode_frame(AVCodecContext * avctx,AVPacket * avpkt,const AVFrame * frame,int * got_packet_ptr)94 static 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)) < 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 static const AVCodecDefault libgsm_defaults[] = {
118 { "b", "13000" },
119 { NULL },
120 };
121
122 #if CONFIG_LIBGSM_ENCODER
123 AVCodec ff_libgsm_encoder = {
124 .name = "libgsm",
125 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
126 .type = AVMEDIA_TYPE_AUDIO,
127 .id = AV_CODEC_ID_GSM,
128 .init = libgsm_encode_init,
129 .encode2 = libgsm_encode_frame,
130 .close = libgsm_encode_close,
131 .defaults = libgsm_defaults,
132 .channel_layouts= (const uint64_t[]) { AV_CH_LAYOUT_MONO, 0 },
133 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
134 AV_SAMPLE_FMT_NONE },
135 .wrapper_name = "libgsm",
136 };
137 #endif
138 #if CONFIG_LIBGSM_MS_ENCODER
139 AVCodec ff_libgsm_ms_encoder = {
140 .name = "libgsm_ms",
141 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
142 .type = AVMEDIA_TYPE_AUDIO,
143 .id = AV_CODEC_ID_GSM_MS,
144 .init = libgsm_encode_init,
145 .encode2 = libgsm_encode_frame,
146 .close = libgsm_encode_close,
147 .defaults = libgsm_defaults,
148 .channel_layouts= (const uint64_t[]) { AV_CH_LAYOUT_MONO, 0 },
149 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
150 AV_SAMPLE_FMT_NONE },
151 .wrapper_name = "libgsm",
152 };
153 #endif
154