[FFmpeg-devel] [PATCH] Mimic decoder

Ramiro Polla ramiro
Thu May 15 05:06:03 CEST 2008

>>>> Attached are the 2 patches I used to test. (lut_calc.diff and 
>>>> lut_static.diff). Anyways, most FFmpeg stuff introduced a considerable 
>>>> speedup over the original code, so I'm tempted to apply one of these two.
>>>> Could I use the hardcoded tables ifdef there?
>>> I dont see much sense in it. I mean the calc code doesnt need the table at
>>> all and needs around 100 byte while the table needs 1024.
>> If it's ok I'd prefer to keep the current code with vlcdec_lookup in 
>> MimicContext.
> You can keep it if you merge the *qscale into the table as its not
> const then anymore ...

Oh, now I get it... Attached patch speeds up by 31%. The official 
encoder and libmimic too IIRC do not change the quality between frames. 
If there are quality changes then this new code probably slows down 
since it'll have to update the table all the time. If I find a case 
where that'll be needed, then I can probably have more tables in the 
context, keep the most recent ones and overwrite old ones. But that's 
for later.

Ramiro Polla
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