FFmpeg
adxdec.c
Go to the documentation of this file.
1 /*
2  * ADX ADPCM codecs
3  * Copyright (c) 2001,2003 BERO
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 "libavutil/intreadwrite.h"
23 #include "avcodec.h"
24 #include "adx.h"
25 #include "get_bits.h"
26 #include "internal.h"
27 
28 /**
29  * @file
30  * SEGA CRI adx codecs.
31  *
32  * Reference documents:
33  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
34  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
35  */
36 
38 {
39  ADXContext *c = avctx->priv_data;
40  int ret, header_size;
41 
42  if (avctx->extradata_size >= 24) {
43  if ((ret = ff_adx_decode_header(avctx, avctx->extradata,
44  avctx->extradata_size, &header_size,
45  c->coeff)) < 0) {
46  av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
47  return AVERROR_INVALIDDATA;
48  }
49  c->channels = avctx->channels;
50  c->header_parsed = 1;
51  }
52 
54 
55  return 0;
56 }
57 
58 /**
59  * Decode 32 samples from 18 bytes.
60  *
61  * A 16-bit scalar value is applied to 32 residuals, which then have a
62  * 2nd-order LPC filter applied to it to form the output signal for a single
63  * channel.
64  */
65 static int adx_decode(ADXContext *c, int16_t *out, int offset,
66  const uint8_t *in, int ch)
67 {
68  ADXChannelState *prev = &c->prev[ch];
69  GetBitContext gb;
70  int scale = AV_RB16(in);
71  int i;
72  int s0, s1, s2, d;
73 
74  /* check if this is an EOF packet */
75  if (scale & 0x8000)
76  return -1;
77 
78  init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
79  out += offset;
80  s1 = prev->s1;
81  s2 = prev->s2;
82  for (i = 0; i < BLOCK_SAMPLES; i++) {
83  d = get_sbits(&gb, 4);
84  s0 = d * scale + ((c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS);
85  s2 = s1;
86  s1 = av_clip_int16(s0);
87  *out++ = s1;
88  }
89  prev->s1 = s1;
90  prev->s2 = s2;
91 
92  return 0;
93 }
94 
95 static int adx_decode_frame(AVCodecContext *avctx, void *data,
96  int *got_frame_ptr, AVPacket *avpkt)
97 {
98  AVFrame *frame = data;
99  int buf_size = avpkt->size;
100  ADXContext *c = avctx->priv_data;
101  int16_t **samples;
102  int samples_offset;
103  const uint8_t *buf = avpkt->data;
104  const uint8_t *buf_end = buf + avpkt->size;
105  int num_blocks, ch, ret;
106  size_t new_extradata_size;
107  uint8_t *new_extradata;
108 
109  new_extradata = av_packet_get_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA,
110  &new_extradata_size);
111  if (new_extradata && new_extradata_size > 0) {
112  int header_size;
113  if ((ret = ff_adx_decode_header(avctx, new_extradata,
114  new_extradata_size, &header_size,
115  c->coeff)) < 0) {
116  av_log(avctx, AV_LOG_ERROR, "error parsing new ADX extradata\n");
117  return AVERROR_INVALIDDATA;
118  }
119 
120  c->eof = 0;
121  }
122 
123  if (c->eof) {
124  *got_frame_ptr = 0;
125  return buf_size;
126  }
127 
128  if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
129  int header_size;
130  if ((ret = ff_adx_decode_header(avctx, buf, buf_size, &header_size,
131  c->coeff)) < 0) {
132  av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
133  return AVERROR_INVALIDDATA;
134  }
135  c->channels = avctx->channels;
136  c->header_parsed = 1;
137  if (buf_size < header_size)
138  return AVERROR_INVALIDDATA;
139  buf += header_size;
140  buf_size -= header_size;
141  }
142  if (!c->header_parsed)
143  return AVERROR_INVALIDDATA;
144 
145  /* calculate number of blocks in the packet */
146  num_blocks = buf_size / (BLOCK_SIZE * c->channels);
147 
148  /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
149  packet */
150  if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
151  if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
152  c->eof = 1;
153  *got_frame_ptr = 0;
154  return avpkt->size;
155  }
156  return AVERROR_INVALIDDATA;
157  }
158 
159  /* get output buffer */
160  frame->nb_samples = num_blocks * BLOCK_SAMPLES;
161  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
162  return ret;
163  samples = (int16_t **)frame->extended_data;
164  samples_offset = 0;
165 
166  while (num_blocks--) {
167  for (ch = 0; ch < c->channels; ch++) {
168  if (buf_end - buf < BLOCK_SIZE || adx_decode(c, samples[ch], samples_offset, buf, ch)) {
169  c->eof = 1;
170  buf = avpkt->data + avpkt->size;
171  break;
172  }
173  buf_size -= BLOCK_SIZE;
174  buf += BLOCK_SIZE;
175  }
176  if (!c->eof)
177  samples_offset += BLOCK_SAMPLES;
178  }
179 
180  frame->nb_samples = samples_offset;
181  *got_frame_ptr = 1;
182 
183  return buf - avpkt->data;
184 }
185 
186 static void adx_decode_flush(AVCodecContext *avctx)
187 {
188  ADXContext *c = avctx->priv_data;
189  memset(c->prev, 0, sizeof(c->prev));
190  c->eof = 0;
191 }
192 
194  .name = "adpcm_adx",
195  .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
196  .type = AVMEDIA_TYPE_AUDIO,
197  .id = AV_CODEC_ID_ADPCM_ADX,
198  .priv_data_size = sizeof(ADXContext),
202  .capabilities = AV_CODEC_CAP_CHANNEL_CONF |
204  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
206  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
207 };
AVCodec
AVCodec.
Definition: codec.h:197
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:41
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
ADXChannelState::s2
int s2
Definition: adx.h:39
out
FILE * out
Definition: movenc.c:54
adx_decode_flush
static void adx_decode_flush(AVCodecContext *avctx)
Definition: adxdec.c:186
sample_fmts
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:953
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
BLOCK_SAMPLES
#define BLOCK_SAMPLES
Definition: adxdec.c:31
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:365
data
const char data[16]
Definition: mxf.c:142
adx_decode
static int adx_decode(ADXContext *c, int16_t *out, int offset, const uint8_t *in, int ch)
Decode 32 samples from 18 bytes.
Definition: adxdec.c:65
ADXChannelState::s1
int s1
Definition: adx.h:39
init_get_bits
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:659
GetBitContext
Definition: get_bits.h:61
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:181
av_cold
#define av_cold
Definition: attributes.h:90
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
AVCodecContext::extradata_size
int extradata_size
Definition: avcodec.h:603
BLOCK_SIZE
#define BLOCK_SIZE
Definition: adxdec.c:30
intreadwrite.h
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
s1
#define s1
Definition: regdef.h:38
get_sbits
static int get_sbits(GetBitContext *s, int n)
Definition: get_bits.h:359
get_bits.h
av_clip_int16
#define av_clip_int16
Definition: common.h:137
flush
static void flush(AVCodecContext *avctx)
Definition: aacdec_template.c:592
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
adx_decode_init
static av_cold int adx_decode_init(AVCodecContext *avctx)
Definition: adxdec.c:37
AV_CODEC_CAP_CHANNEL_CONF
#define AV_CODEC_CAP_CHANNEL_CONF
Codec should fill in channel configuration and samplerate instead of container.
Definition: codec.h:104
s2
#define s2
Definition: regdef.h:39
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1638
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AV_CODEC_ID_ADPCM_ADX
@ AV_CODEC_ID_ADPCM_ADX
Definition: codec_id.h:360
AVPacket::size
int size
Definition: packet.h:366
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
AVCodecContext::sample_fmt
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1106
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
AV_SAMPLE_FMT_S16P
@ AV_SAMPLE_FMT_S16P
signed 16 bits, planar
Definition: samplefmt.h:67
AVCodecContext::channels
int channels
number of audio channels
Definition: avcodec.h:1099
i
int i
Definition: input.c:407
ADXChannelState
Definition: adx.h:38
AVCodecContext::extradata
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:602
av_packet_get_side_data
uint8_t * av_packet_get_side_data(const AVPacket *pkt, enum AVPacketSideDataType type, size_t *size)
Get side information from packet.
Definition: avpacket.c:241
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
ff_adpcm_adx_decoder
const AVCodec ff_adpcm_adx_decoder
Definition: adxdec.c:193
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
avcodec.h
ret
ret
Definition: filter_design.txt:187
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
AVCodecContext
main external API structure.
Definition: avcodec.h:501
AV_PKT_DATA_NEW_EXTRADATA
@ AV_PKT_DATA_NEW_EXTRADATA
The AV_PKT_DATA_NEW_EXTRADATA is used to notify the codec or the format that the extradata buffer was...
Definition: packet.h:55
samples
Filter the word “frame” indicates either a video frame or a group of audio samples
Definition: filter_design.txt:8
ADXContext
Definition: adx.h:42
COEFF_BITS
#define COEFF_BITS
Definition: adx.h:51
adx.h
s0
#define s0
Definition: regdef.h:37
AVPacket
This structure stores compressed data.
Definition: packet.h:342
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:528
d
d
Definition: ffmpeg_filter.c:156
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ff_adx_decode_header
int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, int bufsize, int *header_size, int *coeff)
Decode ADX stream header.
Definition: adx.c:38
adx_decode_frame
static int adx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: adxdec.c:95
AV_RB16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:98