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/*
* RAW DTS demuxer
* Copyright (c) 2008 Benjamin Larsson
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/crc.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/dca.h"
#include "libavcodec/dca_syncwords.h"
#include "libavcodec/get_bits.h"
#include "avformat.h"
#include "demux.h"
#include "rawdec.h"
static int dts_probe(const AVProbeData *p)
{
const uint8_t *buf, *bufp;
uint32_t state = -1;
int markers[4*16] = {0};
int exss_markers = 0, exss_nextpos = 0;
int sum, max, pos, ret, i;
int64_t diff = 0;
int diffcount = 1;
uint8_t hdr[DCA_CORE_FRAME_HEADER_SIZE + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 };
for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) {
int marker, wide_hdr, hdr_size, framesize;
DCACoreFrameHeader h;
GetBitContext gb;
bufp = buf = p->buf + pos;
state = (state << 16) | bytestream_get_be16(&bufp);
if (pos >= 4) {
if (AV_RL16(buf) || AV_RL16(buf-4)) {
diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4));
diffcount ++;
}
}
/* extension substream (EXSS) */
if (state == DCA_SYNCWORD_SUBSTREAM) {
if (pos < exss_nextpos)
continue;
init_get_bits(&gb, buf - 2, 96);
skip_bits_long(&gb, 42);
wide_hdr = get_bits1(&gb);
hdr_size = get_bits(&gb, 8 + 4 * wide_hdr) + 1;
framesize = get_bits(&gb, 16 + 4 * wide_hdr) + 1;
if (hdr_size & 3 || framesize & 3)
continue;
if (hdr_size < 16 || framesize < hdr_size)
continue;
if (pos - 2 + hdr_size > p->buf_size)
continue;
if (av_crc(av_crc_get_table(AV_CRC_16_CCITT), 0xffff, buf + 3, hdr_size - 5))
continue;
if (pos == exss_nextpos)
exss_markers++;
else
exss_markers = FFMAX(1, exss_markers - 1);
exss_nextpos = pos + framesize;
continue;
}
/* regular bitstream */
if (state == DCA_SYNCWORD_CORE_BE &&
(bytestream_get_be16(&bufp) & 0xFC00) == 0xFC00)
marker = 0;
else if (state == DCA_SYNCWORD_CORE_LE &&
(bytestream_get_be16(&bufp) & 0x00FC) == 0x00FC)
marker = 1;
/* 14 bits big-endian bitstream */
else if (state == DCA_SYNCWORD_CORE_14B_BE &&
(bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
marker = 2;
/* 14 bits little-endian bitstream */
else if (state == DCA_SYNCWORD_CORE_14B_LE &&
(bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
marker = 3;
else
continue;
if ((ret = avpriv_dca_convert_bitstream(buf - 2, DCA_CORE_FRAME_HEADER_SIZE,
hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0)
continue;
if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
continue;
marker += 4 * h.sr_code;
markers[marker] ++;
}
if (exss_markers > 3)
return AVPROBE_SCORE_EXTENSION + 1;
sum = max = 0;
for (i=0; i<FF_ARRAY_ELEMS(markers); i++) {
sum += markers[i];
if (markers[max] < markers[i])
max = i;
}
if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
markers[max] * 4 > sum * 3 &&
diff / diffcount > 600)
return AVPROBE_SCORE_EXTENSION + 1;
return 0;
}
const FFInputFormat ff_dts_demuxer = {
.p.name = "dts",
.p.long_name = NULL_IF_CONFIG_SMALL("raw DTS"),
.p.flags = AVFMT_GENERIC_INDEX,
.p.extensions = "dts",
.p.priv_class = &ff_raw_demuxer_class,
.read_probe = dts_probe,
.read_header = ff_raw_audio_read_header,
.read_packet = ff_raw_read_partial_packet,
.raw_codec_id = AV_CODEC_ID_DTS,
.priv_data_size = sizeof(FFRawDemuxerContext),
};
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