1
0
mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-11-21 10:55:51 +02:00
FFmpeg/libavformat/dtsdec.c
Michael Niedermayer f6d1b18b3d avformat/rawdec: Make the raw packet size configurable
This allows testing parsers with a wider range of input packet sizes.
Which is important and usefull for regression testing, some of our
parsers in fact to not work if the packet size is changed from 1024

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2019-07-17 23:18:50 +02:00

142 lines
4.6 KiB
C

/*
* 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 "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;
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)
diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4));
/* 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 / p->buf_size > 200)
return AVPROBE_SCORE_EXTENSION + 1;
return 0;
}
FF_RAW_DEMUXER_CLASS(dts)
AVInputFormat ff_dts_demuxer = {
.name = "dts",
.long_name = NULL_IF_CONFIG_SMALL("raw DTS"),
.read_probe = dts_probe,
.read_header = ff_raw_audio_read_header,
.read_packet = ff_raw_read_partial_packet,
.flags = AVFMT_GENERIC_INDEX,
.extensions = "dts",
.raw_codec_id = AV_CODEC_ID_DTS,
.priv_data_size = sizeof(FFRawDemuxerContext),
.priv_class = &dts_demuxer_class,};