2 * Copyright (C) 2008 Jaikrishnan Menon
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * supports: fibonacci delta encoding
25 * : exponential encoding
27 * For more information about the 8SVX format:
28 * http://netghost.narod.ru/gff/vendspec/iff/iff.txt
29 * http://sox.sourceforge.net/AudioFormats-11.html
30 * http://aminet.net/package/mus/misc/wavepak
31 * http://amigan.1emu.net/reg/8SVX.txt
33 * Samples can be found here:
34 * http://aminet.net/mods/smpl/
39 /** decoder context */
40 typedef struct EightSvxContext {
45 static const int16_t fibonacci[16] = { -34<<8, -21<<8, -13<<8, -8<<8, -5<<8, -3<<8, -2<<8, -1<<8,
46 0, 1<<8, 2<<8, 3<<8, 5<<8, 8<<8, 13<<8, 21<<8 };
47 static const int16_t exponential[16] = { -128<<8, -64<<8, -32<<8, -16<<8, -8<<8, -4<<8, -2<<8, -1<<8,
48 0, 1<<8, 2<<8, 4<<8, 8<<8, 16<<8, 32<<8, 64<<8 };
51 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
54 const uint8_t *buf = avpkt->data;
55 int buf_size = avpkt->size;
56 EightSvxContext *esc = avctx->priv_data;
57 int16_t *out_data = data;
58 int consumed = buf_size;
59 const uint8_t *buf_end = buf + buf_size;
61 if((*data_size >> 2) < buf_size)
64 if(avctx->frame_number == 0) {
65 esc->fib_acc = buf[1] << 8;
70 *data_size = buf_size << 2;
72 while(buf < buf_end) {
74 esc->fib_acc += esc->table[d & 0x0f];
75 *out_data++ = esc->fib_acc;
76 esc->fib_acc += esc->table[d >> 4];
77 *out_data++ = esc->fib_acc;
83 /** initialize 8svx decoder */
84 static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
86 EightSvxContext *esc = avctx->priv_data;
88 switch(avctx->codec->id) {
89 case CODEC_ID_8SVX_FIB:
90 esc->table = fibonacci;
92 case CODEC_ID_8SVX_EXP:
93 esc->table = exponential;
98 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
102 AVCodec ff_eightsvx_fib_decoder = {
104 .type = AVMEDIA_TYPE_AUDIO,
105 .id = CODEC_ID_8SVX_FIB,
106 .priv_data_size = sizeof (EightSvxContext),
107 .init = eightsvx_decode_init,
108 .decode = eightsvx_decode_frame,
109 .long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
112 AVCodec ff_eightsvx_exp_decoder = {
114 .type = AVMEDIA_TYPE_AUDIO,
115 .id = CODEC_ID_8SVX_EXP,
116 .priv_data_size = sizeof (EightSvxContext),
117 .init = eightsvx_decode_init,
118 .decode = eightsvx_decode_frame,
119 .long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),