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spelling/phrasing fixes, mostly by Mans

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Originally committed as revision 4378 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Diego Biurrun 2005-06-11 18:18:13 +00:00
parent 79cc8267f4
commit c5a44f5715
1 changed files with 9 additions and 8 deletions
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17
doc/optimization.txt
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@ -1,7 +1,7 @@
optimization Tips (for libavcodec): optimization Tips (for libavcodec):
What to optimize: What to optimize:
If you plan to do non-x86 architecture specific optimiztions (SIMD normally) If you plan to do non-x86 architecture specific optimizations (SIMD normally),
then take a look in the i386/ directory, as most important functions are then take a look in the i386/ directory, as most important functions are
already optimized for MMX. already optimized for MMX.
@ -14,10 +14,11 @@ As many functions, like the C ones tend to be a bit unreadable currently
because of optimizations it is difficult to understand them (and write because of optimizations it is difficult to understand them (and write
architecture specific versions, or optimize the C functions further) it is architecture specific versions, or optimize the C functions further) it is
recommended to look at older CVS versions of the interesting files (just use recommended to look at older CVS versions of the interesting files (just use
ViewCVS at http://www1.mplayerhq.hu/cgi-bin/cvsweb.cgi/ffmpeg/?cvsroot=FFMpeg) ViewCVS at http://www1.mplayerhq.hu/cgi-bin/cvsweb.cgi/ffmpeg/?cvsroot=FFMpeg).
or perhaps look into the other architecture-specific versions in i386/, ppc/, Alternatively, look into the other architecture-specific versions in the i386/,
alpha/, ... Even if you don't understand the instructions exactly it could ppc/, alpha/ subdirectories. Even if you don't exactly understand the
help understanding the functions & how they can be optimized. instructions, it could help understanding the functions and how they
can be optimized.
NOTE: If you still don't understand some function, ask at our mailing list!!! NOTE: If you still don't understand some function, ask at our mailing list!!!
(http://www1.mplayerhq.hu/mailman/listinfo/ffmpeg-devel) (http://www1.mplayerhq.hu/mailman/listinfo/ffmpeg-devel)
@ -33,7 +34,7 @@ put(_no_rnd)_pixels{,_x2,_y2,_xy2}
avg_pixels{,_x2,_y2,_xy2} avg_pixels{,_x2,_y2,_xy2}
Used in motion compensation of B-frames. Used in motion compensation of B-frames.
These are less important then the put*pixels functions. These are less important than the put*pixels functions.
avg_no_rnd_pixels* avg_no_rnd_pixels*
unused unused
@ -43,7 +44,7 @@ pix_abs16x16{,_x2,_y2,_xy2}
pix_abs8x8{,_x2,_y2,_xy2} pix_abs8x8{,_x2,_y2,_xy2}
Used in motion estimation (encoding) with SAD of MPEG-4 4MV only. Used in motion estimation (encoding) with SAD of MPEG-4 4MV only.
These are less important then the pix_abs16x16* functions. These are less important than the pix_abs16x16* functions.
put_mspel8_mc* / wmv2_mspel8* put_mspel8_mc* / wmv2_mspel8*
Used only in WMV2. Used only in WMV2.
@ -128,7 +129,7 @@ BTW, most of these functions are in dsputil.c/.h, some are in mpegvideo.c/.h.
Alignment: Alignment:
Some instructions on some architectures have strict alignment restrictions, Some instructions on some architectures have strict alignment restrictions,
for example most SSE/SSE2 inctructios on x86. for example most SSE/SSE2 instructions on x86.
The minimum guaranteed alignment is written in the .h files, for example: The minimum guaranteed alignment is written in the .h files, for example:
void (*put_pixels_clamped)(const DCTELEM *block/*align 16*/, UINT8 *pixels/*align 8*/, int line_size); void (*put_pixels_clamped)(const DCTELEM *block/*align 16*/, UINT8 *pixels/*align 8*/, int line_size);