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1 | /* |
2 | * Interface to libgsm for GSM 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 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 | ||
40 | #include "avcodec.h" | |
41 | #include "internal.h" | |
42 | #include "gsm.h" | |
43 | ||
44 | typedef struct LibGSMDecodeContext { | |
45 | struct gsm_state *state; | |
46 | } LibGSMDecodeContext; | |
47 | ||
48 | static av_cold int libgsm_decode_init(AVCodecContext *avctx) { | |
49 | LibGSMDecodeContext *s = avctx->priv_data; | |
50 | ||
51 | avctx->channels = 1; | |
52 | avctx->channel_layout = AV_CH_LAYOUT_MONO; | |
53 | if (!avctx->sample_rate) | |
54 | avctx->sample_rate = 8000; | |
55 | avctx->sample_fmt = AV_SAMPLE_FMT_S16; | |
56 | ||
57 | s->state = gsm_create(); | |
58 | ||
59 | switch(avctx->codec_id) { | |
60 | case AV_CODEC_ID_GSM: | |
61 | avctx->frame_size = GSM_FRAME_SIZE; | |
62 | avctx->block_align = GSM_BLOCK_SIZE; | |
63 | break; | |
64 | case AV_CODEC_ID_GSM_MS: { | |
65 | int one = 1; | |
66 | gsm_option(s->state, GSM_OPT_WAV49, &one); | |
67 | avctx->frame_size = 2 * GSM_FRAME_SIZE; | |
68 | avctx->block_align = GSM_MS_BLOCK_SIZE; | |
69 | } | |
70 | } | |
71 | ||
72 | return 0; | |
73 | } | |
74 | ||
75 | static av_cold int libgsm_decode_close(AVCodecContext *avctx) { | |
76 | LibGSMDecodeContext *s = avctx->priv_data; | |
77 | ||
78 | gsm_destroy(s->state); | |
79 | s->state = NULL; | |
80 | return 0; | |
81 | } | |
82 | ||
83 | static int libgsm_decode_frame(AVCodecContext *avctx, void *data, | |
84 | int *got_frame_ptr, AVPacket *avpkt) | |
85 | { | |
86 | int i, ret; | |
87 | LibGSMDecodeContext *s = avctx->priv_data; | |
88 | AVFrame *frame = data; | |
89 | uint8_t *buf = avpkt->data; | |
90 | int buf_size = avpkt->size; | |
91 | int16_t *samples; | |
92 | ||
93 | if (buf_size < avctx->block_align) { | |
94 | av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); | |
95 | return AVERROR_INVALIDDATA; | |
96 | } | |
97 | ||
98 | /* get output buffer */ | |
99 | frame->nb_samples = avctx->frame_size; | |
100 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) | |
101 | return ret; | |
102 | samples = (int16_t *)frame->data[0]; | |
103 | ||
104 | for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) { | |
105 | if ((ret = gsm_decode(s->state, buf, samples)) < 0) | |
106 | return -1; | |
107 | buf += GSM_BLOCK_SIZE; | |
108 | samples += GSM_FRAME_SIZE; | |
109 | } | |
110 | ||
111 | *got_frame_ptr = 1; | |
112 | ||
113 | return avctx->block_align; | |
114 | } | |
115 | ||
116 | static void libgsm_flush(AVCodecContext *avctx) { | |
117 | LibGSMDecodeContext *s = avctx->priv_data; | |
118 | int one = 1; | |
119 | ||
120 | gsm_destroy(s->state); | |
121 | s->state = gsm_create(); | |
122 | if (avctx->codec_id == AV_CODEC_ID_GSM_MS) | |
123 | gsm_option(s->state, GSM_OPT_WAV49, &one); | |
124 | } | |
125 | ||
126 | #if CONFIG_LIBGSM_DECODER | |
127 | AVCodec ff_libgsm_decoder = { | |
128 | .name = "libgsm", | |
129 | .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"), | |
130 | .type = AVMEDIA_TYPE_AUDIO, | |
131 | .id = AV_CODEC_ID_GSM, | |
132 | .priv_data_size = sizeof(LibGSMDecodeContext), | |
133 | .init = libgsm_decode_init, | |
134 | .close = libgsm_decode_close, | |
135 | .decode = libgsm_decode_frame, | |
136 | .flush = libgsm_flush, | |
137 | .capabilities = CODEC_CAP_DR1, | |
138 | }; | |
139 | #endif | |
140 | #if CONFIG_LIBGSM_MS_DECODER | |
141 | AVCodec ff_libgsm_ms_decoder = { | |
142 | .name = "libgsm_ms", | |
143 | .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"), | |
144 | .type = AVMEDIA_TYPE_AUDIO, | |
145 | .id = AV_CODEC_ID_GSM_MS, | |
146 | .priv_data_size = sizeof(LibGSMDecodeContext), | |
147 | .init = libgsm_decode_init, | |
148 | .close = libgsm_decode_close, | |
149 | .decode = libgsm_decode_frame, | |
150 | .flush = libgsm_flush, | |
151 | .capabilities = CODEC_CAP_DR1, | |
152 | }; | |
153 | #endif |