blob: a503215f679b0be08590e3f2e3c2caaad06ce52d
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 = AV_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 = AV_CODEC_CAP_DR1, |
152 | }; |
153 | #endif |
154 |