Libav
8svx.c
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1 /*
2  * 8SVX audio decoder
3  * Copyright (C) 2008 Jaikrishnan Menon
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
31 #include "avcodec.h"
32 #include "internal.h"
33 #include "libavutil/common.h"
34 
36 typedef struct EightSvxContext {
38  const int8_t *table;
39 
40  /* buffer used to store the whole first packet.
41  data is only sent as one large packet */
43  int data_size;
44  int data_idx;
46 
47 static const int8_t fibonacci[16] = { -34, -21, -13, -8, -5, -3, -2, -1,
48  0, 1, 2, 3, 5, 8, 13, 21 };
49 static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1,
50  0, 1, 2, 4, 8, 16, 32, 64 };
51 
52 #define MAX_FRAME_SIZE 32768
53 
60 static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
61  uint8_t *state, const int8_t *table)
62 {
63  uint8_t val = *state;
64 
65  while (src_size--) {
66  uint8_t d = *src++;
67  val = av_clip_uint8(val + table[d & 0xF]);
68  *dst++ = val;
69  val = av_clip_uint8(val + table[d >> 4]);
70  *dst++ = val;
71  }
72 
73  *state = val;
74 }
75 
76 static void raw_decode(uint8_t *dst, const int8_t *src, int src_size)
77 {
78  while (src_size--)
79  *dst++ = *src++ + 128;
80 }
81 
83 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
84  int *got_frame_ptr, AVPacket *avpkt)
85 {
86  EightSvxContext *esc = avctx->priv_data;
87  AVFrame *frame = data;
88  int buf_size;
89  int ch, ret;
90  int is_compr = (avctx->codec_id != AV_CODEC_ID_PCM_S8_PLANAR);
91 
92  /* for the first packet, copy data to buffer */
93  if (avpkt->data) {
94  int hdr_size = is_compr ? 2 : 0;
95  int chan_size = (avpkt->size - hdr_size * avctx->channels) / avctx->channels;
96 
97  if (avpkt->size < hdr_size * avctx->channels) {
98  av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
99  return AVERROR(EINVAL);
100  }
101  if (esc->data[0]) {
102  av_log(avctx, AV_LOG_ERROR, "unexpected data after first packet\n");
103  return AVERROR(EINVAL);
104  }
105 
106  if (is_compr) {
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 
112  esc->data_idx = 0;
113  esc->data_size = chan_size;
114  if (!(esc->data[0] = av_malloc(chan_size)))
115  return AVERROR(ENOMEM);
116  if (avctx->channels == 2) {
117  if (!(esc->data[1] = av_malloc(chan_size))) {
118  av_freep(&esc->data[0]);
119  return AVERROR(ENOMEM);
120  }
121  }
122  memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
123  if (avctx->channels == 2)
124  memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
125  }
126  if (!esc->data[0]) {
127  av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
128  return AVERROR(EINVAL);
129  }
130 
131  /* decode next piece of data from the buffer */
132  buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
133  if (buf_size <= 0) {
134  *got_frame_ptr = 0;
135  return avpkt->size;
136  }
137 
138  /* get output buffer */
139  frame->nb_samples = buf_size * (is_compr + 1);
140  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
141  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
142  return ret;
143  }
144 
145  for (ch = 0; ch < avctx->channels; ch++) {
146  if (is_compr) {
147  delta_decode(frame->data[ch], &esc->data[ch][esc->data_idx],
148  buf_size, &esc->fib_acc[ch], esc->table);
149  } else {
150  raw_decode(frame->data[ch], &esc->data[ch][esc->data_idx],
151  buf_size);
152  }
153  }
154 
155  esc->data_idx += buf_size;
156 
157  *got_frame_ptr = 1;
158 
159  return avpkt->size;
160 }
161 
164 {
165  EightSvxContext *esc = avctx->priv_data;
166 
167  if (avctx->channels < 1 || avctx->channels > 2) {
168  av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
169  return AVERROR(EINVAL);
170  }
171 
172  switch(avctx->codec->id) {
174  esc->table = fibonacci;
175  break;
177  esc->table = exponential;
178  break;
180  break;
181  default:
182  return -1;
183  }
184  avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
185 
186  return 0;
187 }
188 
190 {
191  EightSvxContext *esc = avctx->priv_data;
192 
193  av_freep(&esc->data[0]);
194  av_freep(&esc->data[1]);
195 
196  return 0;
197 }
198 
200  .name = "8svx_fib",
201  .long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
202  .type = AVMEDIA_TYPE_AUDIO,
203  .id = AV_CODEC_ID_8SVX_FIB,
204  .priv_data_size = sizeof (EightSvxContext),
208  .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
209  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
211 };
212 
214  .name = "8svx_exp",
215  .long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),
216  .type = AVMEDIA_TYPE_AUDIO,
217  .id = AV_CODEC_ID_8SVX_EXP,
218  .priv_data_size = sizeof (EightSvxContext),
222  .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
223  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
225 };
226 
228  .name = "pcm_s8_planar",
229  .long_name = NULL_IF_CONFIG_SMALL("PCM signed 8-bit planar"),
230  .type = AVMEDIA_TYPE_AUDIO,
232  .priv_data_size = sizeof(EightSvxContext),
236  .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
237  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
239 };