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dirac_parser: Improve parsing and silence pointless warnings

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The parser scans for "BBCD" to appear in the bitstream which indicate a
parse info header and once that happens, checks if the parse offsets are
sane. Since random BBCD strings might appear in the bitstream the parser
will emit a pointless warning if that happens.

This commit improves parsing by checking for a valid parse code as well
as keeping the original checks for valid parse offsets. The warnings
were removed as they serve no real purpose.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
This commit is contained in:
Rostislav Pehlivanov 2016-01-21 15:14:10 +00:00
parent b65efbc0f4
commit a849ebb54e
1 changed files with 16 additions and 9 deletions
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25
libavcodec/dirac_parser.c
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@ -100,7 +100,11 @@ typedef struct DiracParseUnit {
static int unpack_parse_unit(DiracParseUnit *pu, DiracParseContext *pc,
int offset)
{
int i;
int8_t *start;
static const uint8_t valid_pu_types[] = {
0x00, 0x10, 0x20, 0x30, 0x08, 0x48, 0xC8, 0xE8
};
if (offset < 0 || pc->index - 13 < offset)
return 0;
@ -111,17 +115,20 @@ static int unpack_parse_unit(DiracParseUnit *pu, DiracParseContext *pc,
pu->next_pu_offset = AV_RB32(start + 5);
pu->prev_pu_offset = AV_RB32(start + 9);
if (pu->pu_type == 0x10 && pu->next_pu_offset == 0)
pu->next_pu_offset = 13;
/* Check for valid parse code */
for (i = 0; i < 8; i++)
if (valid_pu_types[i] == pu->pu_type)
break;
if (i == 8)
return 0;
if (pu->next_pu_offset && pu->next_pu_offset < 13) {
av_log(NULL, AV_LOG_ERROR, "next_pu_offset %d is invalid\n", pu->next_pu_offset);
if (pu->pu_type == 0x10 && pu->next_pu_offset == 0)
pu->next_pu_offset = 13; /* The length of a parse info header */
/* Check if the parse offsets are somewhat sane */
if ((pu->next_pu_offset && pu->next_pu_offset < 13) ||
(pu->prev_pu_offset && pu->prev_pu_offset < 13))
return 0;
}
if (pu->prev_pu_offset && pu->prev_pu_offset < 13) {
av_log(NULL, AV_LOG_ERROR, "prev_pu_offset %d is invalid\n", pu->prev_pu_offset);
return 0;
}
return 1;
}