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

Panagiotis Issaris takis.issaris
Wed May 23 15:47:16 CEST 2007

Hash: SHA1

Michael Niedermayer wrote:

> On Tue, May 22, 2007 at 07:42:04PM +0200, Aurelien Jacobs wrote:
>> On Tue, 22 May 2007 11:23:15 +0200
>> Panagiotis Issaris <takis.issaris at uhasselt.be> wrote:
>>> Panagiotis Issaris wrote:
>>>> Loren Merritt wrote:
>>>>> 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.
>>>> I see; thanks for the explanation.
>>>> So, I could:
>>>> * Move both functions to dsputil.c as they are only used there.
>>>> * Keep them in h264idct.c, but disable their usage when H.264 decoder
>>>> support is not compiled in. This shouldn't break anything as in that
>>>> case ff_jref_idct4_put() would be used instead for lowres==1.
>>>> Any opinions?
>>> This is an updated patch of above mentioned option 2, which was what the
>>> patch that started this thread did.
>> After some thought, this solution looks ok to me.
>> Michael ?
> ok

With friendly regards,
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