FFmpeg
adx_parser.c
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1 /*
2  * Copyright (c) 2011 Justin Ruggles
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * ADX audio parser
24  *
25  * Splits packets into individual blocks.
26  */
27 
28 #include "libavutil/intreadwrite.h"
29 #include "parser.h"
30 #include "adx.h"
31 
32 typedef struct ADXParseContext {
36  int remaining;
38 
40  AVCodecContext *avctx,
41  const uint8_t **poutbuf, int *poutbuf_size,
42  const uint8_t *buf, int buf_size)
43 {
45  ParseContext *pc = &s->pc;
46  int next = END_NOT_FOUND;
47  int i;
48  uint64_t state = pc->state64;
49 
50  if (!s->header_size) {
51  for (i = 0; i < buf_size; i++) {
52  state = (state << 8) | buf[i];
53  /* check for fixed fields in ADX header for possible match */
54  if ((state & 0xFFFF0000FFFFFF00) == 0x8000000003120400ULL) {
55  int channels = state & 0xFF;
56  int header_size = ((state >> 32) & 0xFFFF) + 4;
57  if (channels > 0 && header_size >= 8) {
58  s->header_size = header_size;
59  s->block_size = BLOCK_SIZE * channels;
60  s->remaining = i - 7 + s->header_size + s->block_size;
61  break;
62  }
63  }
64  }
65  pc->state64 = state;
66  }
67 
68  if (s->header_size) {
69  if (!s->remaining)
70  s->remaining = s->block_size;
71  if (s->remaining <= buf_size) {
72  next = s->remaining;
73  s->remaining = 0;
74  } else
75  s->remaining -= buf_size;
76  } else if (avctx->ch_layout.nb_channels > 0) {
77  if (!s->block_size)
78  s->block_size = avctx->ch_layout.nb_channels * BLOCK_SIZE;
79  if (!s->remaining)
80  s->remaining = s->block_size;
81  if (s->remaining <= buf_size) {
82  next = s->remaining;
83  s->remaining = 0;
84  } else
85  s->remaining -= buf_size;
86  }
87 
88  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
89  *poutbuf = NULL;
90  *poutbuf_size = 0;
91  return buf_size;
92  }
93 
94  s1->duration = BLOCK_SAMPLES;
95 
96  *poutbuf = buf;
97  *poutbuf_size = buf_size;
98  return next;
99 }
100 
103  .priv_data_size = sizeof(ADXParseContext),
104  .parser_parse = adx_parse,
105  .parser_close = ff_parse_close,
106 };
ADXParseContext
Definition: adx_parser.c:32
AVCodecParserContext::duration
int duration
Duration of the current frame.
Definition: avcodec.h:2862
ff_parse_close
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:290
ff_adx_parser
const AVCodecParser ff_adx_parser
Definition: adx_parser.c:101
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:327
ADXParseContext::pc
ParseContext pc
Definition: adx_parser.c:33
ParseContext
Definition: parser.h:28
AVCodecContext::ch_layout
AVChannelLayout ch_layout
Audio channel layout.
Definition: avcodec.h:1071
ADXParseContext::header_size
int header_size
Definition: adx_parser.c:34
ADXParseContext::remaining
int remaining
Definition: adx_parser.c:36
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
BLOCK_SAMPLES
#define BLOCK_SAMPLES
Definition: adx.h:52
channels
channels
Definition: aptx.h:31
NULL
#define NULL
Definition: coverity.c:32
state
static struct @466 state
AV_CODEC_ID_ADPCM_ADX
@ AV_CODEC_ID_ADPCM_ADX
Definition: codec_id.h:382
AVCodecParser::codec_ids
int codec_ids[7]
Definition: avcodec.h:2908
adx_parse
static int adx_parse(AVCodecParserContext *s1, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: adx_parser.c:39
ff_combine_frame
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:203
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
parser.h
AVCodecParserContext
Definition: avcodec.h:2748
AVCodecContext
main external API structure.
Definition: avcodec.h:451
ParseContext::state64
uint64_t state64
contains the last 8 bytes in MSB order
Definition: parser.h:37
adx.h
END_NOT_FOUND
#define END_NOT_FOUND
Definition: parser.h:40
AVCodecParser
Definition: avcodec.h:2907
AVCodecParserContext::priv_data
void * priv_data
Definition: avcodec.h:2749
BLOCK_SIZE
#define BLOCK_SIZE
Definition: adx.h:51
ADXParseContext::block_size
int block_size
Definition: adx_parser.c:35