3 * Copyright (c) 2008 Benjamin Larsson
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavcodec/bytestream.h"
23 #include "libavcodec/dca.h"
24 #include "libavcodec/dca_syncwords.h"
25 #include "libavcodec/get_bits.h"
30 static int dts_probe(AVProbeData *p)
32 const uint8_t *buf, *bufp;
34 int markers[4*16] = {0};
37 uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
39 buf = p->buf + FFMIN(4096, p->buf_size);
41 for(; buf < (p->buf+p->buf_size)-2; buf+=2) {
42 int marker, sample_blocks, sample_rate, sr_code, framesize;
47 state = (state << 16) | bytestream_get_be16(&bufp);
49 if (buf - p->buf >= 4)
50 diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4));
52 /* regular bitstream */
53 if (state == DCA_SYNCWORD_CORE_BE)
55 else if (state == DCA_SYNCWORD_CORE_LE)
58 /* 14 bits big-endian bitstream */
59 else if (state == DCA_SYNCWORD_CORE_14B_BE &&
60 (bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
63 /* 14 bits little-endian bitstream */
64 else if (state == DCA_SYNCWORD_CORE_14B_LE &&
65 (bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
70 if (avpriv_dca_convert_bitstream(buf-2, 12, hdr, 12) < 0)
73 init_get_bits(&gb, hdr, 96);
74 skip_bits_long(&gb, 39);
76 sample_blocks = get_bits(&gb, 7) + 1;
77 if (sample_blocks < 8)
80 framesize = get_bits(&gb, 14) + 1;
85 sr_code = get_bits(&gb, 4);
86 sample_rate = avpriv_dca_sample_rates[sr_code];
94 skip_bits_long(&gb, 9);
95 lfe = get_bits(&gb, 2);
105 for (i=0; i<FF_ARRAY_ELEMS(markers); i++) {
107 if (markers[max] < markers[i])
111 if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
112 markers[max] * 4 > sum * 3 &&
113 diff / p->buf_size > 200)
114 return AVPROBE_SCORE_EXTENSION + 1;
119 AVInputFormat ff_dts_demuxer = {
121 .long_name = NULL_IF_CONFIG_SMALL("raw DTS"),
122 .read_probe = dts_probe,
123 .read_header = ff_raw_audio_read_header,
124 .read_packet = ff_raw_read_partial_packet,
125 .flags = AVFMT_GENERIC_INDEX,
127 .raw_codec_id = AV_CODEC_ID_DTS,