gsmdec: add flush function to reset the decoder state when seeking
[libav.git] / libavcodec / gsmdec.c
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1/*
2 * gsm 06.10 decoder
3 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
4 *
2912e87a 5 * This file is part of Libav.
b576934d 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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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 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 18 * License along with Libav; if not, write to the Free Software
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * GSM decoder
25 */
26
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27#include "avcodec.h"
28#include "get_bits.h"
645e7599 29#include "msgsmdec.h"
b576934d 30
645e7599 31#include "gsmdec_template.c"
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32
33static av_cold int gsm_init(AVCodecContext *avctx)
34{
35 avctx->channels = 1;
36 if (!avctx->sample_rate)
37 avctx->sample_rate = 8000;
5d6e4c16 38 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
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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
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53static 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;
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61 int frame_bytes = avctx->frame_size *
62 av_get_bytes_per_sample(avctx->sample_fmt);
b576934d 63
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64 if (*data_size < frame_bytes) {
65 av_log(avctx, AV_LOG_ERROR, "Output buffer is too small\n");
66 return AVERROR(EINVAL);
67 }
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68 *data_size = 0;
69 if(buf_size < avctx->block_align)
70 return AVERROR_INVALIDDATA;
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71
72 switch (avctx->codec_id) {
73 case CODEC_ID_GSM:
645e7599 74 init_get_bits(&gb, buf, buf_size * 8);
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75 if (get_bits(&gb, 4) != 0xd)
76 av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
77 res = gsm_decode_block(avctx, samples, &gb);
78 if (res < 0)
79 return res;
80 break;
81 case CODEC_ID_GSM_MS:
645e7599 82 res = ff_msgsm_decode_block(avctx, samples, buf);
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83 if (res < 0)
84 return res;
85 }
86 *data_size = frame_bytes;
87 return avctx->block_align;
88}
89
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90static void gsm_flush(AVCodecContext *avctx)
91{
92 GSMContext *s = avctx->priv_data;
93 memset(s, 0, sizeof(*s));
94}
95
d36beb3f 96AVCodec ff_gsm_decoder = {
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97 .name = "gsm",
98 .type = AVMEDIA_TYPE_AUDIO,
99 .id = CODEC_ID_GSM,
100 .priv_data_size = sizeof(GSMContext),
101 .init = gsm_init,
102 .decode = gsm_decode_frame,
fc43fc9f 103 .flush = gsm_flush,
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104 .long_name = NULL_IF_CONFIG_SMALL("GSM"),
105};
106
d36beb3f 107AVCodec ff_gsm_ms_decoder = {
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108 .name = "gsm_ms",
109 .type = AVMEDIA_TYPE_AUDIO,
110 .id = CODEC_ID_GSM_MS,
111 .priv_data_size = sizeof(GSMContext),
112 .init = gsm_init,
113 .decode = gsm_decode_frame,
fc43fc9f 114 .flush = gsm_flush,
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115 .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
116};