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 "bsf.h"
22#include "bsf_internal.h"
23#include "get_bits.h"
24#include "ac3_parser_internal.h"
25
26static int eac3_core_filter(AVBSFContext *ctx, AVPacket *pkt)
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
45    if (hdr.frame_type == EAC3_FRAME_TYPE_INDEPENDENT ||
46        hdr.frame_type == EAC3_FRAME_TYPE_AC3_CONVERT) {
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
61        if (hdr2.frame_type == EAC3_FRAME_TYPE_INDEPENDENT ||
62            hdr2.frame_type == EAC3_FRAME_TYPE_AC3_CONVERT) {
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;
73fail:
74    av_packet_unref(pkt);
75    return ret;
76}
77
78static const enum AVCodecID codec_ids[] = {
79    AV_CODEC_ID_EAC3, AV_CODEC_ID_NONE,
80};
81
82const FFBitStreamFilter ff_eac3_core_bsf = {
83    .p.name      = "eac3_core",
84    .p.codec_ids = codec_ids,
85    .filter      = eac3_core_filter,
86};
87