aac_adtstoasc_bsf.c
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1 /*
2  * MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration bitstream filter
3  * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
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 
22 #include "avcodec.h"
23 #include "aacadtsdec.h"
24 #include "put_bits.h"
25 #include "get_bits.h"
26 #include "mpeg4audio.h"
27 #include "internal.h"
28 
29 typedef struct AACBSFContext {
32 
38  AVCodecContext *avctx, const char *args,
39  uint8_t **poutbuf, int *poutbuf_size,
40  const uint8_t *buf, int buf_size,
41  int keyframe)
42 {
43  GetBitContext gb;
44  PutBitContext pb;
46 
47  AACBSFContext *ctx = bsfc->priv_data;
48 
50 
51  *poutbuf = (uint8_t*) buf;
52  *poutbuf_size = buf_size;
53 
54  if (avctx->extradata)
55  if (show_bits(&gb, 12) != 0xfff)
56  return 0;
57 
58  if (avpriv_aac_parse_header(&gb, &hdr) < 0) {
59  av_log(avctx, AV_LOG_ERROR, "Error parsing ADTS frame header!\n");
60  return -1;
61  }
62 
63  if (!hdr.crc_absent && hdr.num_aac_frames > 1) {
64  av_log_missing_feature(avctx, "Multiple RDBs per frame with CRC", 0);
65  return AVERROR_PATCHWELCOME;
66  }
67 
68  buf += AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
69  buf_size -= AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
70 
71  if (!ctx->first_frame_done) {
72  int pce_size = 0;
73  uint8_t pce_data[MAX_PCE_SIZE];
74  if (!hdr.chan_config) {
75  init_get_bits(&gb, buf, buf_size * 8);
76  if (get_bits(&gb, 3) != 5) {
77  av_log_missing_feature(avctx, "PCE based channel configuration, where the PCE is not the first syntax element", 0);
78  return AVERROR_PATCHWELCOME;
79  }
80  init_put_bits(&pb, pce_data, MAX_PCE_SIZE);
81  pce_size = avpriv_copy_pce_data(&pb, &gb)/8;
82  flush_put_bits(&pb);
83  buf_size -= get_bits_count(&gb)/8;
84  buf += get_bits_count(&gb)/8;
85  }
86  avctx->extradata_size = 2 + pce_size;
88 
89  init_put_bits(&pb, avctx->extradata, avctx->extradata_size);
90  put_bits(&pb, 5, hdr.object_type);
91  put_bits(&pb, 4, hdr.sampling_index);
92  put_bits(&pb, 4, hdr.chan_config);
93  put_bits(&pb, 1, 0); //frame length - 1024 samples
94  put_bits(&pb, 1, 0); //does not depend on core coder
95  put_bits(&pb, 1, 0); //is not extension
96  flush_put_bits(&pb);
97  if (pce_size) {
98  memcpy(avctx->extradata + 2, pce_data, pce_size);
99  }
100 
101  ctx->first_frame_done = 1;
102  }
103 
104  *poutbuf = (uint8_t*) buf;
105  *poutbuf_size = buf_size;
106 
107  return 0;
108 }
109 
111  "aac_adtstoasc",
112  sizeof(AACBSFContext),
114 };
static int aac_adtstoasc_filter(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int keyframe)
This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4 ADTS header and removes the ADTS h...
uint8_t object_type
Definition: aacadtsdec.h:36
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:237
uint8_t
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1454
struct AACBSFContext AACBSFContext
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:192
bitstream reader API header.
uint8_t sampling_index
Definition: aacadtsdec.h:37
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:146
static void put_bits(PutBitContext *s, int n, unsigned int value)
Write up to 31 bits into a bitstream.
Definition: put_bits.h:136
uint8_t chan_config
Definition: aacadtsdec.h:38
uint8_t num_aac_frames
Definition: aacadtsdec.h:39
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:251
#define AAC_ADTS_HEADER_SIZE
Definition: aacadtsdec.h:29
external API header
main external API structure.
Definition: avcodec.h:1339
int avpriv_aac_parse_header(GetBitContext *gbc, AACADTSHeaderInfo *hdr)
Parse AAC frame header.
Definition: aacadtsdec.c:29
int extradata_size
Definition: avcodec.h:1455
void av_log_missing_feature(void *avc, const char *feature, int want_sample)
Log a generic warning message about a missing feature.
Definition: utils.c:2007
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:372
common internal api header.
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:86
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:52
#define MAX_PCE_SIZE
Maximum size of a PCE including the 3-bit ID_PCE.
Definition: mpeg4audio.h:104
AVBitStreamFilter ff_aac_adtstoasc_bsf
int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)
Definition: mpeg4audio.c:155
uint8_t crc_absent
Definition: aacadtsdec.h:35
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:158
bitstream writer API