57286c796f64a0611fd82ba744ffcf7aa4ff8590
[libav.git] / libavcodec / gsmdec.c
1 /*
2 * gsm 06.10 decoder
3 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 "avcodec.h"
28 #include "get_bits.h"
29 #include "msgsmdec.h"
30
31 #include "gsmdec_template.c"
32
33 static av_cold int gsm_init(AVCodecContext *avctx)
34 {
35 avctx->channels = 1;
36 if (!avctx->sample_rate)
37 avctx->sample_rate = 8000;
38 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
39
40 switch (avctx->codec_id) {
41 case CODEC_ID_GSM:
42 avctx->frame_size = GSM_FRAME_SIZE;
43 avctx->block_align = GSM_BLOCK_SIZE;
44 break;
45 case CODEC_ID_GSM_MS:
46 avctx->frame_size = 2 * GSM_FRAME_SIZE;
47 avctx->block_align = GSM_MS_BLOCK_SIZE;
48 }
49
50 return 0;
51 }
52
53 static int gsm_decode_frame(AVCodecContext *avctx, void *data,
54 int *data_size, AVPacket *avpkt)
55 {
56 int res;
57 GetBitContext gb;
58 const uint8_t *buf = avpkt->data;
59 int buf_size = avpkt->size;
60 int16_t *samples = data;
61 int frame_bytes = avctx->frame_size *
62 av_get_bytes_per_sample(avctx->sample_fmt);
63
64 if (*data_size < frame_bytes)
65 return -1;
66 *data_size = 0;
67 if(buf_size < avctx->block_align)
68 return AVERROR_INVALIDDATA;
69
70 switch (avctx->codec_id) {
71 case CODEC_ID_GSM:
72 init_get_bits(&gb, buf, buf_size * 8);
73 if (get_bits(&gb, 4) != 0xd)
74 av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
75 res = gsm_decode_block(avctx, samples, &gb);
76 if (res < 0)
77 return res;
78 break;
79 case CODEC_ID_GSM_MS:
80 res = ff_msgsm_decode_block(avctx, samples, buf);
81 if (res < 0)
82 return res;
83 }
84 *data_size = frame_bytes;
85 return avctx->block_align;
86 }
87
88 AVCodec ff_gsm_decoder = {
89 .name = "gsm",
90 .type = AVMEDIA_TYPE_AUDIO,
91 .id = CODEC_ID_GSM,
92 .priv_data_size = sizeof(GSMContext),
93 .init = gsm_init,
94 .decode = gsm_decode_frame,
95 .long_name = NULL_IF_CONFIG_SMALL("GSM"),
96 };
97
98 AVCodec ff_gsm_ms_decoder = {
99 .name = "gsm_ms",
100 .type = AVMEDIA_TYPE_AUDIO,
101 .id = CODEC_ID_GSM_MS,
102 .priv_data_size = sizeof(GSMContext),
103 .init = gsm_init,
104 .decode = gsm_decode_frame,
105 .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
106 };