FFmpeg
eac3_core_bsf.c
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1 /*
2  * Copyright (c) 2018 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 "get_bits.h"
24 #include "ac3_parser_internal.h"
25 
27 {
28  AC3HeaderInfo hdr;
29  GetBitContext gbc;
30  int ret;
31 
32  ret = ff_bsf_get_packet_ref(ctx, pkt);
33  if (ret < 0)
34  return ret;
35  ret = init_get_bits8(&gbc, pkt->data, pkt->size);
36  if (ret < 0)
37  goto fail;
38 
39  ret = ff_ac3_parse_header(&gbc, &hdr);
40  if (ret < 0) {
41  ret = AVERROR_INVALIDDATA;
42  goto fail;
43  }
44 
47  pkt->size = FFMIN(hdr.frame_size, pkt->size);
48  } else if (hdr.frame_type == EAC3_FRAME_TYPE_DEPENDENT && pkt->size > hdr.frame_size) {
49  AC3HeaderInfo hdr2;
50 
51  ret = init_get_bits8(&gbc, pkt->data + hdr.frame_size, pkt->size - hdr.frame_size);
52  if (ret < 0)
53  goto fail;
54 
55  ret = ff_ac3_parse_header(&gbc, &hdr2);
56  if (ret < 0) {
57  ret = AVERROR_INVALIDDATA;
58  goto fail;
59  }
60 
63  pkt->size -= hdr.frame_size;
64  pkt->data += hdr.frame_size;
65  } else {
66  pkt->size = 0;
67  }
68  } else {
69  pkt->size = 0;
70  }
71 
72  return 0;
73 fail:
74  av_packet_unref(pkt);
75  return ret;
76 }
77 
78 static const enum AVCodecID codec_ids[] = {
80 };
81 
83  .name = "eac3_core",
84  .filter = eac3_core_filter,
85  .codec_ids = codec_ids,
86 };
int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
Parse AC-3 frame header.
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
The bitstream filter state.
Definition: avcodec.h:5759
int size
Definition: avcodec.h:1478
static AVPacket pkt
const char * name
Definition: avcodec.h:5809
uint8_t * data
Definition: avcodec.h:1477
bitstream reader API header.
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:215
uint8_t frame_type
Definition: ac3.h:188
Coded AC-3 header values up to the lfeon element, plus derived values.
Definition: ac3.h:177
#define fail()
Definition: checkasm.h:120
#define FFMIN(a, b)
Definition: common.h:96
AVFormatContext * ctx
Definition: movenc.c:48
static int eac3_core_filter(AVBSFContext *ctx, AVPacket *pkt)
Definition: eac3_core_bsf.c:26
const AVBitStreamFilter ff_eac3_core_bsf
Definition: eac3_core_bsf.c:82
Libavcodec external API header.
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:677
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:599
uint16_t frame_size
Definition: ac3.h:204
This structure stores compressed data.
Definition: avcodec.h:1454
int ff_bsf_get_packet_ref(AVBSFContext *ctx, AVPacket *pkt)
Called by bitstream filters to get packet for filtering.
Definition: bsf.c:238
static enum AVCodecID codec_ids[]
Definition: eac3_core_bsf.c:78