[x264-devel] Re: bug in x264_validate_parameters(...) concerning the "--analyse" argument ?

[Mathieu Carnec]

I know what is a binary "AND" but I hadn't seen the "&" before the "=".
Sorry for that.

It's clear now:
Of course, the lines 447-448 keeps only the interesting bits of
h->param.analyse.inter and sets the other bits to 0.
Line 449 does the same for h->param.analyse.intra.
Line 450 checks that is the user didn't set to 1 the bit corresponding to
ANALYSE_PSUB16x16, then the bit corresponding to X264_ANALYSE_PSUB8x8 should
be set to 0.

Thanks for your replies.

Best regards,

Mathieu.

-----Message d'origine-----
De : x264-devel-bounce at videolan.org
[mailto:x264-devel-bounce at videolan.org]De la part de Mathieu Monnier
Envoyé : jeudi 23 novembre 2006 11:29
À : x264-devel at videolan.org
Objet : [x264-devel] Re: bug in x264_validate_parameters(...) concerning
the "--analyse" argument ?


 > What's the purpose of line 447 which enables X264_ANALYSE_PSUB8x8 (using
 > "....|X264_ANALYSE_PSUB8x8|....") if, on line 450, the condition is
always
 > true and so, on line 451, X264_ANALYSE_PSUB8x8 is disabled ?

line 447 doesn't enable PSUB8x8, it makes a binary "and" ( &= ) on the
flags, in order to restrict a possibly random value ( since it was given
by an user ) to a valid value for the encoder.
line 450 disables PSUB8x8 ( &=~ ) if and only if PSUB16x16 wasn't used (
!& ). That is, I guess, a restriction of the me algorithm. Then again,
it's not always disabled, since if PSUB16x16 was enabled, PSUB8x8 will
be left intact.

Regards,

Mathieu

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