1 /*
2 * gsm 06.10 decoder
3 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * GSM decoder
25 */
26
27 #include "libavutil/channel_layout.h"
28 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "internal.h"
31 #include "msgsmdec.h"
32
33 #include "gsmdec_template.c"
34
gsm_init(AVCodecContext * avctx)35 static av_cold int gsm_init(AVCodecContext *avctx)
36 {
37 avctx->channels = 1;
38 avctx->channel_layout = AV_CH_LAYOUT_MONO;
39 if (!avctx->sample_rate)
40 avctx->sample_rate = 8000;
41 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
42
43 switch (avctx->codec_id) {
44 case AV_CODEC_ID_GSM:
45 avctx->frame_size = GSM_FRAME_SIZE;
46 avctx->block_align = GSM_BLOCK_SIZE;
47 break;
48 case AV_CODEC_ID_GSM_MS:
49 avctx->frame_size = 2 * GSM_FRAME_SIZE;
50 if (!avctx->block_align)
51 avctx->block_align = GSM_MS_BLOCK_SIZE;
52 else
53 if (avctx->block_align < MSN_MIN_BLOCK_SIZE ||
54 avctx->block_align > GSM_MS_BLOCK_SIZE ||
55 (avctx->block_align - MSN_MIN_BLOCK_SIZE) % 3) {
56 av_log(avctx, AV_LOG_ERROR, "Invalid block alignment %d\n",
57 avctx->block_align);
58 return AVERROR_INVALIDDATA;
59 }
60 }
61
62 return 0;
63 }
64
gsm_decode_frame(AVCodecContext * avctx,void * data,int * got_frame_ptr,AVPacket * avpkt)65 static int gsm_decode_frame(AVCodecContext *avctx, void *data,
66 int *got_frame_ptr, AVPacket *avpkt)
67 {
68 AVFrame *frame = data;
69 int res;
70 GetBitContext gb;
71 const uint8_t *buf = avpkt->data;
72 int buf_size = avpkt->size;
73 int16_t *samples;
74
75 if (buf_size < avctx->block_align) {
76 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
77 return AVERROR_INVALIDDATA;
78 }
79
80 /* get output buffer */
81 frame->nb_samples = avctx->frame_size;
82 if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
83 return res;
84 samples = (int16_t *)frame->data[0];
85
86 switch (avctx->codec_id) {
87 case AV_CODEC_ID_GSM:
88 init_get_bits(&gb, buf, buf_size * 8);
89 if (get_bits(&gb, 4) != 0xd)
90 av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
91 res = gsm_decode_block(avctx, samples, &gb, GSM_13000);
92 if (res < 0)
93 return res;
94 break;
95 case AV_CODEC_ID_GSM_MS:
96 res = ff_msgsm_decode_block(avctx, samples, buf,
97 (GSM_MS_BLOCK_SIZE - avctx->block_align) / 3);
98 if (res < 0)
99 return res;
100 }
101
102 *got_frame_ptr = 1;
103
104 return avctx->block_align;
105 }
106
gsm_flush(AVCodecContext * avctx)107 static void gsm_flush(AVCodecContext *avctx)
108 {
109 GSMContext *s = avctx->priv_data;
110 memset(s, 0, sizeof(*s));
111 }
112
113 #if CONFIG_GSM_DECODER
114 AVCodec ff_gsm_decoder = {
115 .name = "gsm",
116 .long_name = NULL_IF_CONFIG_SMALL("GSM"),
117 .type = AVMEDIA_TYPE_AUDIO,
118 .id = AV_CODEC_ID_GSM,
119 .priv_data_size = sizeof(GSMContext),
120 .init = gsm_init,
121 .decode = gsm_decode_frame,
122 .flush = gsm_flush,
123 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
124 };
125 #endif
126 #if CONFIG_GSM_MS_DECODER
127 AVCodec ff_gsm_ms_decoder = {
128 .name = "gsm_ms",
129 .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
130 .type = AVMEDIA_TYPE_AUDIO,
131 .id = AV_CODEC_ID_GSM_MS,
132 .priv_data_size = sizeof(GSMContext),
133 .init = gsm_init,
134 .decode = gsm_decode_frame,
135 .flush = gsm_flush,
136 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
137 };
138 #endif
139