[FFmpeg-trac] #3651(avcodec:open): UT Video Codec is inefficient compared to libutvideo
FFmpeg
trac at avcodec.org
Sun May 25 16:18:46 CEST 2014
#3651: UT Video Codec is inefficient compared to libutvideo
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Reporter: Zerowalker | Owner:
Type: enhancement | Status: open
Priority: wish | Component: avcodec
Version: git-master | Resolution:
Keywords: utvideo | Blocked By:
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
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Comment (by cehoyos):
Replying to [comment:12 Zerowalker]:
> Your UT Video Codec is faster cause of more threads, but slower on the
same, meaning it has less efficiency overall (if i am not mistaken?)
Isn't that what I wrote in comment:5?
> Lagarith is slower cause of some issue, which i don't understand
The original codec implementation uses floating point arithmetic which
will fail on processors != x86 and might fail if you use another compiler.
FFmpeg's implementation is fixed-point (which is what you expect for a
lossless codec) meaning you can compile it for any hardware with any (non-
broken) C compiler and you will always get correct (bitexact) output.
Fixed-point arithmetic is often slower than floating-point on typical
hardware.
See also (for example):
https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2009-September/079680.html
http://mod16.org/hurfdurf/?p=142
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Ticket URL: <https://trac.ffmpeg.org/ticket/3651#comment:13>
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