1 /*
2 * Copyright (C) 2008 Jaikrishnan Menon
3 * Copyright (C) 2011 Stefano Sabatini
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
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 *
12 * FFmpeg is distributed in the hope that it will be useful,
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
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * 8svx audio decoder
25 * @author Jaikrishnan Menon
26 *
27 * supports: fibonacci delta encoding
28 * : exponential encoding
29 *
30 * For more information about the 8SVX format:
31 * http://netghost.narod.ru/gff/vendspec/iff/iff.txt
32 * http://sox.sourceforge.net/AudioFormats-11.html
33 * http://aminet.net/package/mus/misc/wavepak
34 * http://amigan.1emu.net/reg/8SVX.txt
35 *
36 * Samples can be found here:
37 * http://aminet.net/mods/smpl/
38 */
39
40 #include "libavutil/avassert.h"
41 #include "avcodec.h"
42 #include "internal.h"
43 #include "libavutil/common.h"
44
45 /** decoder context */
46 typedef struct EightSvxContext {
47 uint8_t fib_acc[2];
48 const int8_t *table;
49
50 /* buffer used to store the whole first packet.
51 data is only sent as one large packet */
52 uint8_t *data[2];
53 int data_size;
54 int data_idx;
55 } EightSvxContext;
56
57 static const int8_t fibonacci[16] = { -34, -21, -13, -8, -5, -3, -2, -1, 0, 1, 2, 3, 5, 8, 13, 21 };
58 static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1, 0, 1, 2, 4, 8, 16, 32, 64 };
59
60 #define MAX_FRAME_SIZE 2048
61
62 /**
63 * Delta decode the compressed values in src, and put the resulting
64 * decoded samples in dst.
65 *
66 * @param[in,out] state starting value. it is saved for use in the next call.
67 * @param table delta sequence table
68 */
delta_decode(uint8_t * dst,const uint8_t * src,int src_size,uint8_t * state,const int8_t * table)69 static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
70 uint8_t *state, const int8_t *table)
71 {
72 uint8_t val = *state;
73
74 while (src_size--) {
75 uint8_t d = *src++;
76 val = av_clip_uint8(val + table[d & 0xF]);
77 *dst++ = val;
78 val = av_clip_uint8(val + table[d >> 4]);
79 *dst++ = val;
80 }
81
82 *state = val;
83 }
84
85 /** decode a frame */
eightsvx_decode_frame(AVCodecContext * avctx,void * data,int * got_frame_ptr,AVPacket * avpkt)86 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
87 int *got_frame_ptr, AVPacket *avpkt)
88 {
89 EightSvxContext *esc = avctx->priv_data;
90 AVFrame *frame = data;
91 int buf_size;
92 int ch, ret;
93 int hdr_size = 2;
94
95 /* decode and interleave the first packet */
96 if (!esc->data[0] && avpkt) {
97 int chan_size = avpkt->size / avctx->channels - hdr_size;
98
99 if (avpkt->size % avctx->channels) {
100 av_log(avctx, AV_LOG_WARNING, "Packet with odd size, ignoring last byte\n");
101 }
102 if (avpkt->size < (hdr_size + 1) * avctx->channels) {
103 av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
104 return AVERROR_INVALIDDATA;
105 }
106
107 esc->fib_acc[0] = avpkt->data[1] + 128;
108 if (avctx->channels == 2)
109 esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;
110
111 esc->data_idx = 0;
112 esc->data_size = chan_size;
113 if (!(esc->data[0] = av_malloc(chan_size)))
114 return AVERROR(ENOMEM);
115 if (avctx->channels == 2) {
116 if (!(esc->data[1] = av_malloc(chan_size))) {
117 av_freep(&esc->data[0]);
118 return AVERROR(ENOMEM);
119 }
120 }
121 memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
122 if (avctx->channels == 2)
123 memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
124 }
125 if (!esc->data[0]) {
126 av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
127 return AVERROR_INVALIDDATA;
128 }
129
130 /* decode next piece of data from the buffer */
131 buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
132 if (buf_size <= 0) {
133 *got_frame_ptr = 0;
134 return avpkt->size;
135 }
136
137 /* get output buffer */
138 frame->nb_samples = buf_size * 2;
139 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
140 return ret;
141
142 for (ch = 0; ch < avctx->channels; ch++) {
143 delta_decode(frame->data[ch], &esc->data[ch][esc->data_idx],
144 buf_size, &esc->fib_acc[ch], esc->table);
145 }
146
147 esc->data_idx += buf_size;
148
149 *got_frame_ptr = 1;
150
151 return ((avctx->frame_number == 0)*hdr_size + buf_size)*avctx->channels;
152 }
153
eightsvx_decode_init(AVCodecContext * avctx)154 static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
155 {
156 EightSvxContext *esc = avctx->priv_data;
157
158 if (avctx->channels < 1 || avctx->channels > 2) {
159 av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
160 return AVERROR_INVALIDDATA;
161 }
162
163 switch (avctx->codec->id) {
164 case AV_CODEC_ID_8SVX_FIB: esc->table = fibonacci; break;
165 case AV_CODEC_ID_8SVX_EXP: esc->table = exponential; break;
166 default:
167 av_assert1(0);
168 }
169 avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
170
171 return 0;
172 }
173
eightsvx_decode_close(AVCodecContext * avctx)174 static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
175 {
176 EightSvxContext *esc = avctx->priv_data;
177
178 av_freep(&esc->data[0]);
179 av_freep(&esc->data[1]);
180 esc->data_size = 0;
181 esc->data_idx = 0;
182
183 return 0;
184 }
185
186 #if CONFIG_EIGHTSVX_FIB_DECODER
187 AVCodec ff_eightsvx_fib_decoder = {
188 .name = "8svx_fib",
189 .long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
190 .type = AVMEDIA_TYPE_AUDIO,
191 .id = AV_CODEC_ID_8SVX_FIB,
192 .priv_data_size = sizeof (EightSvxContext),
193 .init = eightsvx_decode_init,
194 .decode = eightsvx_decode_frame,
195 .close = eightsvx_decode_close,
196 .capabilities = AV_CODEC_CAP_DR1,
197 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
198 AV_SAMPLE_FMT_NONE },
199 };
200 #endif
201 #if CONFIG_EIGHTSVX_EXP_DECODER
202 AVCodec ff_eightsvx_exp_decoder = {
203 .name = "8svx_exp",
204 .long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),
205 .type = AVMEDIA_TYPE_AUDIO,
206 .id = AV_CODEC_ID_8SVX_EXP,
207 .priv_data_size = sizeof (EightSvxContext),
208 .init = eightsvx_decode_init,
209 .decode = eightsvx_decode_frame,
210 .close = eightsvx_decode_close,
211 .capabilities = AV_CODEC_CAP_DR1,
212 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
213 AV_SAMPLE_FMT_NONE },
214 };
215 #endif
216