mp4: Don't read an empty Decoder Config Descriptor
[libav.git] / libavcodec / 8svx.c
CommitLineData
cb21e0a7 1/*
4477dedc 2 * 8SVX audio decoder
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3 * Copyright (C) 2008 Jaikrishnan Menon
4 *
2912e87a 5 * This file is part of Libav.
cb21e0a7 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/**
ba87f080 23 * @file
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24 * 8svx audio decoder
25 * @author Jaikrishnan Menon
ec679eb4 26 *
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27 * supports: fibonacci delta encoding
28 * : exponential encoding
29 */
30
31#include "avcodec.h"
32
1b41f260 33/** decoder context */
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34typedef struct EightSvxContext {
35 int16_t fib_acc;
19998314 36 const int16_t *table;
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37} EightSvxContext;
38
6dbfb7de 39static const int16_t fibonacci[16] = { -34<<8, -21<<8, -13<<8, -8<<8, -5<<8, -3<<8, -2<<8, -1<<8,
cb21e0a7 40 0, 1<<8, 2<<8, 3<<8, 5<<8, 8<<8, 13<<8, 21<<8 };
6dbfb7de 41static const int16_t exponential[16] = { -128<<8, -64<<8, -32<<8, -16<<8, -8<<8, -4<<8, -2<<8, -1<<8,
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42 0, 1<<8, 2<<8, 4<<8, 8<<8, 16<<8, 32<<8, 64<<8 };
43
1b41f260 44/** decode a frame */
cb21e0a7 45static int eightsvx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
7a00bbad 46 AVPacket *avpkt)
cb21e0a7 47{
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48 const uint8_t *buf = avpkt->data;
49 int buf_size = avpkt->size;
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50 EightSvxContext *esc = avctx->priv_data;
51 int16_t *out_data = data;
52 int consumed = buf_size;
53 const uint8_t *buf_end = buf + buf_size;
54
55 if((*data_size >> 2) < buf_size)
56 return -1;
57
58 if(avctx->frame_number == 0) {
59 esc->fib_acc = buf[1] << 8;
60 buf_size -= 2;
61 buf += 2;
62 }
63
64 *data_size = buf_size << 2;
65
66 while(buf < buf_end) {
67 uint8_t d = *buf++;
68 esc->fib_acc += esc->table[d & 0x0f];
69 *out_data++ = esc->fib_acc;
70 esc->fib_acc += esc->table[d >> 4];
71 *out_data++ = esc->fib_acc;
72 }
73
74 return consumed;
75}
76
1b41f260 77/** initialize 8svx decoder */
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78static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
79{
80 EightSvxContext *esc = avctx->priv_data;
81
82 switch(avctx->codec->id) {
83 case CODEC_ID_8SVX_FIB:
84 esc->table = fibonacci;
85 break;
86 case CODEC_ID_8SVX_EXP:
87 esc->table = exponential;
88 break;
89 default:
90 return -1;
91 }
5d6e4c16 92 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
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93 return 0;
94}
95
d36beb3f 96AVCodec ff_eightsvx_fib_decoder = {
99e3913d 97 .name = "8svx_fib",
72415b2a 98 .type = AVMEDIA_TYPE_AUDIO,
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99 .id = CODEC_ID_8SVX_FIB,
100 .priv_data_size = sizeof (EightSvxContext),
101 .init = eightsvx_decode_init,
102 .decode = eightsvx_decode_frame,
fe4bf374 103 .long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
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104};
105
d36beb3f 106AVCodec ff_eightsvx_exp_decoder = {
99e3913d 107 .name = "8svx_exp",
72415b2a 108 .type = AVMEDIA_TYPE_AUDIO,
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109 .id = CODEC_ID_8SVX_EXP,
110 .priv_data_size = sizeof (EightSvxContext),
111 .init = eightsvx_decode_init,
112 .decode = eightsvx_decode_frame,
fe4bf374 113 .long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),
cb21e0a7 114};