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avformat/dtsdec: detect core-less streams

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Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
foo86 2016-05-03 16:06:41 +03:00 • committed by James Almer
parent fe483ac428
commit bb7c558070
1 changed files with 40 additions and 7 deletions
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47
libavformat/dtsdec.c
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@ -19,6 +19,8 @@
* 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"
@ -32,23 +34,51 @@ static int dts_probe(AVProbeData *p)
const uint8_t *buf, *bufp;
uint32_t state = -1;
int markers[4*16] = {0};
int sum, max, i;
int exss_markers = 0, exss_nextpos = 0;
int sum, max, pos, i;
int64_t diff = 0;
uint8_t hdr[12 + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 };
const AVCRC *crctab = av_crc_get_table(AV_CRC_16_CCITT);
buf = p->buf + FFMIN(4096, p->buf_size);
for(; buf < (p->buf+p->buf_size)-2; buf+=2) {
for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) {
int marker, sample_blocks, sample_rate, sr_code, framesize;
int lfe;
int lfe, wide_hdr, hdr_size;
GetBitContext gb;
bufp = buf;
bufp = buf = p->buf + pos;
state = (state << 16) | bytestream_get_be16(&bufp);
if (buf - p->buf >= 4)
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(crctab, 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)
@ -103,6 +133,9 @@ static int dts_probe(AVProbeData *p)
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];