[FFmpeg-devel] [PATCH] Make h264idct.c compilation optional

Loren Merritt lorenm
Mon May 14 16:39:52 CEST 2007

On Mon, 14 May 2007, Aurelien Jacobs wrote:
> Panagiotis Issaris wrote:
>> The attached patch tries to make the h264idct.c compilation optional.
>> Not meant for direct inclusion, as I am not sure about the correctness...
>> In dsputil_init() currently [1], for lowres decoding, when idct_algo's
>> other than FF_IDCT_INT or FF_IDCT_AUTO are selected, h264 related
>> functions (ff_h264_lowres_idct_put|add_c) are being used. Are these two
>> functions in fact more generic then their name implies (in fact just
>> misnamed), and should they be relocated to some other common file?
>> Or are they really H.264 specific functions? ... but in that case it
>> seems weird that selecting f.e. FF_IDCT_VP3 or FF_IDCT_SIMPLEMMX would
>> result in using these H.264 specific functions.
> Patch seems ok, but I also would like to hear first what's the purpose
> of ff_h264_lowres_idct_put/add_c (is it h264 only or more general ?).

ff_h264_lowres_idct* are not used in h264. They're so named because 
they apply h264's idct algo to other codecs, when whe user requests 
non-standards-compliant speedups. They're not the default because they're 
even less precise than the other lowres idct.

--Loren Merritt

More information about the ffmpeg-devel mailing list