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Document that the MPEG12 "fast" functions can read out of bounds.

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This is intentional (and a reason why fast usually should not be used),
but a few people sent patches to "fix" this recently so it would be
better to document this.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
This commit is contained in:
Reimar Döffinger 2012-09-15 18:22:21 +02:00
parent 2599541b3d
commit 3905caf251
1 changed files with 15 additions and 0 deletions
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15
libavcodec/mpeg12.c
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@ -232,6 +232,11 @@ end:
return 0;
}
/**
* Note: this function can read out of range and crash for corrupt streams.
* Changing this would eat up any speed benefits it has.
* Do not use "fast" flag if you need the code to be robust.
*/
static inline int mpeg1_fast_decode_block_inter(MpegEncContext *s, DCTELEM *block, int n)
{
int level, i, j, run;
@ -383,6 +388,11 @@ end:
return 0;
}
/**
* Note: this function can read out of range and crash for corrupt streams.
* Changing this would eat up any speed benefits it has.
* Do not use "fast" flag if you need the code to be robust.
*/
static inline int mpeg2_fast_decode_block_non_intra(MpegEncContext *s,
DCTELEM *block, int n)
{
@ -523,6 +533,11 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s, DCTELEM *block, in
return 0;
}
/**
* Note: this function can read out of range and crash for corrupt streams.
* Changing this would eat up any speed benefits it has.
* Do not use "fast" flag if you need the code to be robust.
*/
static inline int mpeg2_fast_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n)
{
int level, dc, diff, j, run;