2 * Copyright (c) 2018 Paul B Mahol
4 * This file is part of FFmpeg.
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.
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.
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
24 #include "mlp_parse.h"
27 typedef struct AccessUnit {
33 typedef struct TrueHDCoreContext {
39 static int truehd_core_filter(AVBSFContext *ctx, AVPacket *pkt)
41 TrueHDCoreContext *s = ctx->priv_data;
43 AccessUnit units[MAX_SUBSTREAMS];
44 int ret, i, last_offset = 0;
45 int in_size, out_size;
47 int substream_bytes = 0;
50 ret = ff_bsf_get_packet_ref(ctx, pkt);
55 ret = AVERROR_INVALIDDATA;
59 in_size = (AV_RB16(pkt->data) & 0xFFF) * 2;
60 if (in_size < 4 || in_size > pkt->size) {
61 ret = AVERROR_INVALIDDATA;
65 ret = init_get_bits8(&gbc, pkt->data + 4, pkt->size - 4);
69 if (show_bits_long(&gbc, 32) == 0xf8726fba) {
70 if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) < 0)
75 if (s->hdr.num_substreams > MAX_SUBSTREAMS) {
76 ret = AVERROR_INVALIDDATA;
80 for (i = 0; i < s->hdr.num_substreams; i++) {
81 for (int j = 0; j < 4; j++)
82 units[i].bits[j] = get_bits1(&gbc);
84 units[i].offset = get_bits(&gbc, 12);
86 last_offset = units[i].offset * 2;
90 if (units[i].bits[0]) {
91 units[i].optional = get_bits(&gbc, 16);
96 end = get_bits_count(&gbc) >> 3;
98 out_size = end + 4 + last_offset;
99 if (out_size < in_size) {
100 int bpos = 0, reduce = end - have_header * 28 - substream_bytes;
101 uint16_t parity_nibble, dts = AV_RB16(pkt->data + 2);
105 av_assert1(reduce >= 0 && reduce % 2 == 0);
108 memcpy(header, pkt->data + 4, 28);
109 header[16] = (header[16] & 0x0c) | (FFMIN(s->hdr.num_substreams, 3) << 4);
112 AV_WL16(header + 26, ff_mlp_checksum16(header, 26));
117 pkt->size = out_size;
119 ret = av_packet_make_writable(pkt);
123 AV_WB16(pkt->data + 2, dts);
125 parity_nibble ^= out_size / 2;
127 for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
128 uint16_t substr_hdr = 0;
130 substr_hdr |= (units[i].bits[0] << 15);
131 substr_hdr |= (units[i].bits[1] << 14);
132 substr_hdr |= (units[i].bits[2] << 13);
133 substr_hdr |= (units[i].bits[3] << 12);
134 substr_hdr |= units[i].offset;
136 AV_WB16(pkt->data + have_header * 28 + 4 + bpos, substr_hdr);
138 parity_nibble ^= substr_hdr;
141 if (units[i].bits[0]) {
142 AV_WB16(pkt->data + have_header * 28 + 4 + bpos, units[i].optional);
144 parity_nibble ^= units[i].optional;
149 parity_nibble ^= parity_nibble >> 8;
150 parity_nibble ^= parity_nibble >> 4;
151 parity_nibble &= 0xF;
153 auheader = (parity_nibble ^ 0xF) << 12;
154 auheader |= (out_size / 2) & 0x0fff;
155 AV_WB16(pkt->data, auheader);
158 memcpy(pkt->data + 4, header, 28);
163 av_packet_unref(pkt);
168 static void truehd_core_flush(AVBSFContext *ctx)
170 TrueHDCoreContext *s = ctx->priv_data;
171 memset(&s->hdr, 0, sizeof(s->hdr));
174 static const enum AVCodecID codec_ids[] = {
175 AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
178 const AVBitStreamFilter ff_truehd_core_bsf = {
179 .name = "truehd_core",
180 .priv_data_size = sizeof(TrueHDCoreContext),
181 .filter = truehd_core_filter,
182 .flush = truehd_core_flush,
183 .codec_ids = codec_ids,