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dca_core_bsf.c
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1 /*
2  * Copyright (c) 2016 Paul B Mahol
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 #include "avcodec.h"
22 #include "bsf.h"
23 #include "bytestream.h"
24 #include "dca_syncwords.h"
25 #include "libavutil/mem.h"
26 
28 {
29  GetByteContext gb;
30  uint32_t syncword;
31  int core_size = 0, ret;
32 
33  ret = ff_bsf_get_packet_ref(ctx, pkt);
34  if (ret < 0)
35  return ret;
36 
37  bytestream2_init(&gb, pkt->data, pkt->size);
38  syncword = bytestream2_get_be32(&gb);
39  bytestream2_skip(&gb, 1);
40 
41  switch (syncword) {
43  core_size = ((bytestream2_get_be24(&gb) >> 4) & 0x3fff) + 1;
44  break;
45  }
46 
47  if (core_size > 0 && core_size <= pkt->size) {
48  pkt->size = core_size;
49  }
50 
51  return 0;
52 }
53 
54 static const enum AVCodecID codec_ids[] = {
56 };
57 
59  .name = "dca_core",
60  .filter = dca_core_filter,
61  .codec_ids = codec_ids,
62 };
Memory handling functions.
The bitstream filter state.
Definition: avcodec.h:5720
int size
Definition: avcodec.h:1453
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:133
static AVPacket pkt
const char * name
Definition: avcodec.h:5770
uint8_t * data
Definition: avcodec.h:1452
static int dca_core_filter(AVBSFContext *ctx, AVPacket *pkt)
Definition: dca_core_bsf.c:27
ptrdiff_t size
Definition: opengl_enc.c:101
#define DCA_SYNCWORD_CORE_BE
Definition: dca_syncwords.h:22
const AVBitStreamFilter ff_dca_core_bsf
Definition: dca_core_bsf.c:58
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:215
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:164
AVFormatContext * ctx
Definition: movenc.c:48
Libavcodec external API header.
static enum AVCodecID codec_ids[]
Definition: dca_core_bsf.c:54
This structure stores compressed data.
Definition: avcodec.h:1429
int ff_bsf_get_packet_ref(AVBSFContext *ctx, AVPacket *pkt)
Called by bitstream filters to get packet for filtering.
Definition: bsf.c:238