Andreas Rheinhardt 5315d12139 avcodec/encode: Don't issue emms after encode callback ...

It is no longer necessary: Most encoders don't use any MMX code
at all any more and the ones that do issue emms on their own.
Instead add an ff_asser1_fpu() to check that it stays that way.

To add some more information, only the halfpel (and fullpel),
qpel and motion estimation APIs use MMX in addition to the
SBC and Snow specific dsp code. halfpel is used by the
mpegvideo encoders, SVQ1 and Snow encoders. The same
encoders in addition to the AC-3 ones and dvvideo use me_cmp.
qpel is only used by the MPEG4 encoder which is part of
mpegvideo. None of these codecs need the generic emms_c (even on
errors):

a) The AC-3 encoders only use a width 16 me_cmp function which
can no longer use MMX since d91b1559e0.
b) dvvideo and SBC emit emms on their own and have no error paths
after the start of the part that can use MMX.
c) SVQ1 calls emms_c() on its own, even on all error paths
that need it.
d) Snow calls emms_c() on its ordinary (success) return path;
it has only one error path in the part of the code that uses MMX,
but even it is fine as ratecontrol_1pass() always calls emms_c()
itself.
e) For mpegvideo, the MMX code is almost confined to the part
of the code reachable from the worker threads (if slice threading
is in use). The exception to this is in skip_check() which always
calls emms_c() itself. Because encode_picture() always calls
emms_c() itself after executing the worker threads and before any
error condition, the floating point state is clean upon exit from
encode_picture().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

2026-03-02 12:01:15 +01:00

31 KiB

Raw Blame History

View Raw