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ws-snd1.c
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1 /*
2  * Westwood SNDx codecs
3  * Copyright (c) 2005 Konstantin Shishkov
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 #include <stdint.h>
23 
25 #include "libavutil/common.h"
26 #include "libavutil/intreadwrite.h"
27 #include "avcodec.h"
28 #include "internal.h"
29 
30 /**
31  * @file
32  * Westwood SNDx codecs
33  *
34  * Reference documents about VQA format and its audio codecs
35  * can be found here:
36  * http://www.multimedia.cx
37  */
38 
39 static const int8_t ws_adpcm_4bit[] = {
40  -9, -8, -6, -5, -4, -3, -2, -1,
41  0, 1, 2, 3, 4, 5, 6, 8
42 };
43 
45 {
46  avctx->channels = 1;
49 
50  return 0;
51 }
52 
53 static int ws_snd_decode_frame(AVCodecContext *avctx, void *data,
54  int *got_frame_ptr, AVPacket *avpkt)
55 {
56  AVFrame *frame = data;
57  const uint8_t *buf = avpkt->data;
58  int buf_size = avpkt->size;
59 
60  int in_size, out_size, ret;
61  int sample = 128;
62  uint8_t *samples;
63  uint8_t *samples_end;
64 
65  if (!buf_size)
66  return 0;
67 
68  if (buf_size < 4) {
69  av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
70  return AVERROR(EINVAL);
71  }
72 
73  out_size = AV_RL16(&buf[0]);
74  in_size = AV_RL16(&buf[2]);
75  buf += 4;
76 
77  if (in_size > buf_size) {
78  av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");
79  return AVERROR_INVALIDDATA;
80  }
81 
82  /* get output buffer */
83  frame->nb_samples = out_size;
84  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
85  return ret;
86  samples = frame->data[0];
87  samples_end = samples + out_size;
88 
89  if (in_size == out_size) {
90  memcpy(samples, buf, out_size);
91  *got_frame_ptr = 1;
92  return buf_size;
93  }
94 
95  while (samples < samples_end && buf - avpkt->data < buf_size) {
96  int code, smp, size;
97  uint8_t count;
98  code = *buf >> 6;
99  count = *buf & 0x3F;
100  buf++;
101 
102  /* make sure we don't write past the output buffer */
103  switch (code) {
104  case 0: smp = 4 * (count + 1); break;
105  case 1: smp = 2 * (count + 1); break;
106  case 2: smp = (count & 0x20) ? 1 : count + 1; break;
107  default: smp = count + 1; break;
108  }
109  if (samples_end - samples < smp)
110  break;
111 
112  /* make sure we don't read past the input buffer */
113  size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1;
114  if ((buf - avpkt->data) + size > buf_size)
115  break;
116 
117  switch (code) {
118  case 0: /* ADPCM 2-bit */
119  for (count++; count > 0; count--) {
120  code = *buf++;
121  sample += ( code & 0x3) - 2;
122  sample = av_clip_uint8(sample);
123  *samples++ = sample;
124  sample += ((code >> 2) & 0x3) - 2;
125  sample = av_clip_uint8(sample);
126  *samples++ = sample;
127  sample += ((code >> 4) & 0x3) - 2;
128  sample = av_clip_uint8(sample);
129  *samples++ = sample;
130  sample += (code >> 6) - 2;
131  sample = av_clip_uint8(sample);
132  *samples++ = sample;
133  }
134  break;
135  case 1: /* ADPCM 4-bit */
136  for (count++; count > 0; count--) {
137  code = *buf++;
138  sample += ws_adpcm_4bit[code & 0xF];
139  sample = av_clip_uint8(sample);
140  *samples++ = sample;
141  sample += ws_adpcm_4bit[code >> 4];
142  sample = av_clip_uint8(sample);
143  *samples++ = sample;
144  }
145  break;
146  case 2: /* no compression */
147  if (count & 0x20) { /* big delta */
148  int8_t t;
149  t = count;
150  t <<= 3;
151  sample += t >> 3;
152  sample = av_clip_uint8(sample);
153  *samples++ = sample;
154  } else { /* copy */
155  memcpy(samples, buf, smp);
156  samples += smp;
157  buf += smp;
158  sample = buf[-1];
159  }
160  break;
161  default: /* run */
162  memset(samples, sample, smp);
163  samples += smp;
164  }
165  }
166 
167  frame->nb_samples = samples - frame->data[0];
168  *got_frame_ptr = 1;
169 
170  return buf_size;
171 }
172 
174  .name = "ws_snd1",
175  .long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"),
176  .type = AVMEDIA_TYPE_AUDIO,
178  .init = ws_snd_decode_init,
179  .decode = ws_snd_decode_frame,
180  .capabilities = AV_CODEC_CAP_DR1,
181 };
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
int size
Definition: avcodec.h:1602
int out_size
Definition: movenc.c:55
static av_cold int ws_snd_decode_init(AVCodecContext *avctx)
Definition: ws-snd1.c:44
#define sample
AVCodec.
Definition: avcodec.h:3601
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:87
AVCodec ff_ws_snd1_decoder
Definition: ws-snd1.c:173
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2446
uint8_t
#define av_cold
Definition: attributes.h:82
AV_SAMPLE_FMT_U8
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1601
ptrdiff_t size
Definition: opengl_enc.c:101
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
const char * name
Name of the codec implementation.
Definition: avcodec.h:3608
GLsizei count
Definition: opengl_enc.c:109
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2489
audio channel layout utility functions
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1676
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:947
void * buf
Definition: avisynth_c.h:690
static const int8_t ws_adpcm_4bit[]
Definition: ws-snd1.c:39
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
common internal api header.
common internal and external API header
int channels
number of audio channels
Definition: avcodec.h:2439
#define AV_CH_LAYOUT_MONO
static int ws_snd_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: ws-snd1.c:53
This structure stores compressed data.
Definition: avcodec.h:1578
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:241
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:959