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
dca_core_filter(AVBSFContext * ctx,AVPacket * pkt)26 static int dca_core_filter(AVBSFContext *ctx, AVPacket *pkt)
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) {
41 case DCA_SYNCWORD_CORE_BE:
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[] = {
54 AV_CODEC_ID_DTS, AV_CODEC_ID_NONE,
55 };
56
57 const AVBitStreamFilter ff_dca_core_bsf = {
58 .name = "dca_core",
59 .filter = dca_core_filter,
60 .codec_ids = codec_ids,
61 };
62