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avformat/dtsdec: switch to common frame header parsing function 

This makes probing for regular DTS more strict because more header
fields are checked and values not supported by decoder are now rejected.

Also fixes an issue original code had with 14-bit streams: 96 bits of
header were expected, however only 84 bits were converted, which was not
enough to parse LFE flag.

Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
foo86 2017-07-10 17:11:36 +03:00 committed by James Almer
parent e54b9be1ff
commit 3b7ec920af
1 changed files with 11 additions and 32 deletions
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43
libavformat/dtsdec.c
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@ -35,13 +35,13 @@ static int dts_probe(AVProbeData *p)
uint32_t state = -1;
int markers[4*16] = {0};
int exss_markers = 0, exss_nextpos = 0;
int sum, max, pos, i;
int sum, max, pos, ret, i;
int64_t diff = 0;
uint8_t hdr[12 + AV_INPUT_BUFFER_PADDING_SIZE] = { 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, sample_blocks, sample_rate, sr_code, framesize;
int lfe, wide_hdr, hdr_size;
int marker, wide_hdr, hdr_size, framesize;
DCACoreFrameHeader h;
GetBitContext gb;
bufp = buf = p->buf + pos;
@ -98,36 +98,15 @@ static int dts_probe(AVProbeData *p)
else
continue;
if (avpriv_dca_convert_bitstream(buf-2, 12, hdr, 12) < 0)
if ((ret = avpriv_dca_convert_bitstream(buf - 2, DCA_CORE_FRAME_HEADER_SIZE,
hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0)
continue;
if (init_get_bits8(&gb, hdr, ret) < 0)
continue;
if (avpriv_dca_parse_core_frame_header(&gb, &h) < 0)
continue;
init_get_bits(&gb, hdr, 96);
skip_bits_long(&gb, 39);
sample_blocks = get_bits(&gb, 7) + 1;
if (sample_blocks < 8)
continue;
framesize = get_bits(&gb, 14) + 1;
if (framesize < 95)
continue;
skip_bits(&gb, 6);
sr_code = get_bits(&gb, 4);
sample_rate = avpriv_dca_sample_rates[sr_code];
if (sample_rate == 0)
continue;
get_bits(&gb, 5);
if (get_bits(&gb, 1))
continue;
skip_bits_long(&gb, 9);
lfe = get_bits(&gb, 2);
if (lfe > 2)
continue;
marker += 4* sr_code;
marker += 4 * h.sr_code;
markers[marker] ++;
}