FFmpeg
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 "bsf.h"
22 #include "bsf_internal.h"
23 #include "bytestream.h"
24 #include "dca_syncwords.h"
25 
27 {
28  GetByteContext gb;
29  uint32_t syncword;
30  int core_size = 0, ret;
31 
32  ret = ff_bsf_get_packet_ref(ctx, pkt);
33  if (ret < 0)
34  return ret;
35 
36  bytestream2_init(&gb, pkt->data, pkt->size);
37  syncword = bytestream2_get_be32(&gb);
38  bytestream2_skip(&gb, 1);
39 
40  switch (syncword) {
42  core_size = ((bytestream2_get_be24(&gb) >> 4) & 0x3fff) + 1;
43  break;
44  }
45 
46  if (core_size > 0 && core_size <= pkt->size) {
47  pkt->size = core_size;
48  }
49 
50  return 0;
51 }
52 
53 static const enum AVCodecID codec_ids[] = {
55 };
56 
58  .name = "dca_core",
59  .filter = dca_core_filter,
60  .codec_ids = codec_ids,
61 };
The bitstream filter state.
Definition: bsf.h:49
int size
Definition: packet.h:356
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: bsf.h:99
uint8_t * data
Definition: packet.h:355
static int dca_core_filter(AVBSFContext *ctx, AVPacket *pkt)
Definition: dca_core_bsf.c:26
ptrdiff_t size
Definition: opengl_enc.c:100
#define DCA_SYNCWORD_CORE_BE
Definition: dca_syncwords.h:22
const AVBitStreamFilter ff_dca_core_bsf
Definition: dca_core_bsf.c:57
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:46
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:164
AVFormatContext * ctx
Definition: movenc.c:48
static enum AVCodecID codec_ids[]
Definition: dca_core_bsf.c:53
This structure stores compressed data.
Definition: packet.h:332
int ff_bsf_get_packet_ref(AVBSFContext *ctx, AVPacket *pkt)
Called by bitstream filters to get packet for filtering.
Definition: bsf.c:252