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opus_parser.c
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1 /*
2  * Copyright (c) 2013-2014 Mozilla Corporation
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  * Opus parser
24  *
25  * Determines the duration for each packet.
26  */
27 
28 #include "avcodec.h"
29 #include "bytestream.h"
30 #include "opus.h"
31 #include "parser.h"
32 
33 typedef struct OpusParseContext {
40 
41 static const uint8_t *parse_opus_ts_header(const uint8_t *start, int *payload_len, int buf_len)
42 {
43  const uint8_t *buf = start + 1;
44  int start_trim_flag, end_trim_flag, control_extension_flag, control_extension_length;
45  uint8_t flags;
46 
47  GetByteContext gb;
48  bytestream2_init(&gb, buf, buf_len);
49 
50  flags = bytestream2_get_byte(&gb);
51  start_trim_flag = (flags >> 4) & 1;
52  end_trim_flag = (flags >> 3) & 1;
53  control_extension_flag = (flags >> 2) & 1;
54 
55  *payload_len = 0;
56  while (bytestream2_peek_byte(&gb) == 0xff)
57  *payload_len += bytestream2_get_byte(&gb);
58 
59  *payload_len += bytestream2_get_byte(&gb);
60 
61  if (start_trim_flag)
62  bytestream2_skip(&gb, 2);
63  if (end_trim_flag)
64  bytestream2_skip(&gb, 2);
65  if (control_extension_flag) {
66  control_extension_length = bytestream2_get_byte(&gb);
67  bytestream2_skip(&gb, control_extension_length);
68  }
69 
70  return buf + bytestream2_tell(&gb);
71 }
72 
73 /**
74  * Find the end of the current frame in the bitstream.
75  * @return the position of the first byte of the next frame, or -1
76  */
78  const uint8_t *buf, int buf_size, int *header_len)
79 {
81  ParseContext *pc = &s->pc;
82  int ret, start_found, i = 0, payload_len = 0;
83  const uint8_t *payload;
84  uint32_t state;
85  uint16_t hdr;
86  *header_len = 0;
87 
88  if (!buf_size)
89  return 0;
90 
91  start_found = pc->frame_start_found;
92  state = pc->state;
93  payload = buf;
94 
95  /* Check if we're using Opus in MPEG-TS framing */
96  if (!s->ts_framing && buf_size > 2) {
97  hdr = AV_RB16(buf);
98  if ((hdr & OPUS_TS_MASK) == OPUS_TS_HEADER)
99  s->ts_framing = 1;
100  }
101 
102  if (s->ts_framing && !start_found) {
103  for (i = 0; i < buf_size-2; i++) {
104  state = (state << 8) | payload[i];
105  if ((state & OPUS_TS_MASK) == OPUS_TS_HEADER) {
106  payload = parse_opus_ts_header(payload, &payload_len, buf_size - i);
107  *header_len = payload - buf;
108  start_found = 1;
109  break;
110  }
111  }
112  }
113 
114  if (!s->ts_framing)
115  payload_len = buf_size;
116 
117  if (avctx->extradata && !s->extradata_parsed) {
118  ret = ff_opus_parse_extradata(avctx, &s->ctx);
119  if (ret < 0) {
120  av_log(avctx, AV_LOG_ERROR, "Error parsing Ogg extradata.\n");
121  return AVERROR_INVALIDDATA;
122  }
124  s->extradata_parsed = 1;
125  }
126 
127  if (payload_len <= buf_size && (!s->ts_framing || start_found)) {
128  ret = ff_opus_parse_packet(&s->pkt, payload, payload_len, s->ctx.nb_streams > 1);
129  if (ret < 0) {
130  av_log(avctx, AV_LOG_ERROR, "Error parsing Opus packet header.\n");
131  pc->frame_start_found = 0;
132  return AVERROR_INVALIDDATA;
133  }
134 
135  ctx->duration = s->pkt.frame_count * s->pkt.frame_duration;
136  }
137 
138  if (s->ts_framing) {
139  if (start_found) {
140  if (payload_len + *header_len <= buf_size) {
141  pc->frame_start_found = 0;
142  pc->state = -1;
143  return payload_len + *header_len;
144  }
145  }
146 
147  pc->frame_start_found = start_found;
148  pc->state = state;
149  return END_NOT_FOUND;
150  }
151 
152  return buf_size;
153 }
154 
156  const uint8_t **poutbuf, int *poutbuf_size,
157  const uint8_t *buf, int buf_size)
158 {
159  OpusParseContext *s = ctx->priv_data;
160  ParseContext *pc = &s->pc;
161  int next, header_len;
162 
163  next = opus_find_frame_end(ctx, avctx, buf, buf_size, &header_len);
164 
165  if (s->ts_framing && next != AVERROR_INVALIDDATA &&
166  ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
167  *poutbuf = NULL;
168  *poutbuf_size = 0;
169  return buf_size;
170  }
171 
172  if (next == AVERROR_INVALIDDATA){
173  *poutbuf = NULL;
174  *poutbuf_size = 0;
175  return buf_size;
176  }
177 
178  *poutbuf = buf + header_len;
179  *poutbuf_size = buf_size - header_len;
180  return next;
181 }
182 
185  .priv_data_size = sizeof(OpusParseContext),
186  .parser_parse = opus_parse,
187  .parser_close = ff_parse_close
188 };
int ff_opus_parse_packet(OpusPacket *pkt, const uint8_t *buf, int buf_size, int self_delimiting)
Parse Opus packet info from raw packet data.
Definition: opus.c:90
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int frame_count
frame count
Definition: opus.h:92
int codec_ids[5]
Definition: avcodec.h:5083
static const uint8_t * parse_opus_ts_header(const uint8_t *start, int *payload_len, int buf_len)
Definition: opus_parser.c:41
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:133
int duration
Duration of the current frame.
Definition: avcodec.h:5037
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:87
int frame_start_found
Definition: parser.h:34
uint8_t
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1588
static struct @281 state
#define OPUS_TS_HEADER
Definition: opus.h:53
static int flags
Definition: log.c:57
#define av_log(a,...)
#define OPUS_TS_MASK
Definition: opus.h:54
ChannelMap * channel_maps
Definition: opus.h:173
int nb_streams
Definition: opus.h:166
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
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:251
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:164
ParseContext pc
Definition: opus_parser.c:34
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:329
int frame_duration
frame duration, in samples @ 48kHz
Definition: opus.h:95
AVFormatContext * ctx
Definition: movenc.c:48
static av_always_inline int bytestream2_tell(GetByteContext *g)
Definition: bytestream.h:188
static int opus_parse(AVCodecParserContext *ctx, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: opus_parser.c:155
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1488
void * buf
Definition: avisynth_c.h:690
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
static int opus_find_frame_end(AVCodecParserContext *ctx, AVCodecContext *avctx, const uint8_t *buf, int buf_size, int *header_len)
Find the end of the current frame in the bitstream.
Definition: opus_parser.c:77
#define END_NOT_FOUND
Definition: parser.h:40
OpusContext ctx
Definition: opus_parser.c:35
OpusPacket pkt
Definition: opus_parser.c:36
AVCodecParser ff_opus_parser
Definition: opus_parser.c:183
av_cold int ff_opus_parse_extradata(AVCodecContext *avctx, OpusContext *s)
Definition: opus.c:291
#define av_freep(p)
void INT64 start
Definition: avisynth_c.h:690