FFmpeg: libavcodec/8svx.c Source File

FFmpeg
8svx.c
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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  */
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 */
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(EINVAL);
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(EINVAL);
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 
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_log(avctx, AV_LOG_ERROR, "Invalid codec id %d.\n", avctx->codec->id);
168  return AVERROR_INVALIDDATA;
169  }
170  avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
171 
172  return 0;
173 }
174 
175  static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
176 {
177  EightSvxContext *esc = avctx->priv_data;
178 
179  av_freep(&esc->data[0]);
180  av_freep(&esc->data[1]);
181  esc->data_size = 0;
182  esc->data_idx = 0;
183 
184  return 0;
185 }
186 
187 #if CONFIG_EIGHTSVX_FIB_DECODER
188 AVCodec ff_eightsvx_fib_decoder = {
189  .name = "8svx_fib",
190  .long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
191  .type = AVMEDIA_TYPE_AUDIO,
192  .id = AV_CODEC_ID_8SVX_FIB,
193  .priv_data_size = sizeof (EightSvxContext),
194  .init = eightsvx_decode_init,
195  .decode = eightsvx_decode_frame,
196  .close = eightsvx_decode_close,
197  .capabilities = CODEC_CAP_DR1,
198  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
199  AV_SAMPLE_FMT_NONE },
200 };
201 #endif
202 #if CONFIG_EIGHTSVX_EXP_DECODER
203 AVCodec ff_eightsvx_exp_decoder = {
204  .name = "8svx_exp",
205  .long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),
206  .type = AVMEDIA_TYPE_AUDIO,
207  .id = AV_CODEC_ID_8SVX_EXP,
208  .priv_data_size = sizeof (EightSvxContext),
209  .init = eightsvx_decode_init,
210  .decode = eightsvx_decode_frame,
211  .close = eightsvx_decode_close,
212  .capabilities = CODEC_CAP_DR1,
213  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
214  AV_SAMPLE_FMT_NONE },
215 };
216 #endif
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