[XviD-devel] Get Assert problem with Debug version of 1.2.2

[Radek Czyz]

Hi,
Yes it's an assert I added long ago, after discovering that our mv cost 
calculation is in fact not right.
However I never found a way to get our cost calculation always right 
while keeping it at least remotely as fast. And it is speed-critical code.

I think we need to concede that our cost is an approximation (correct 
for majority of MVs, and for huge majority of practically-encountered 
MVs) and remove the assert.

Unless somebody has a better idea? :)

Radek

Vico Sohu wrote:
> Hi, All,
> 
>       When I use debug mode of version 1.2.2, always get problem at mbcoding.c (in folder \bitstream) :
> 
>  if (!pMB->mcsel)
>   for (i = 0; i < (pMB->mode == MODE_INTER4V ? 4 : 1); i++) {
>    CodeVector(bs, pMB->pmvs[i].x, frame->fcode);
>    CodeVector(bs, pMB->pmvs[i].y, frame->fcode);
> 
> #ifdef _DEBUG
>    if (i == 0) /* for simplicity */ {
>     int coded_length = BitstreamPos(bs) - bits;
>     int estimated_length = d_mv_bits(pMB->pmvs[i].x, pMB->pmvs[i].y, zeroMV, frame->fcode, 0);
>     assert(estimated_length == coded_length);
>     d_mv_bits(pMB->pmvs[i].x, pMB->pmvs[i].y, zeroMV, frame->fcode, 0);
>    }
> #endif
>   }
> 
> estimated_length IS OFTEN NOT EQUAL TO  coded_length.   so assert error always happen.
> Maybe latest version should modify this code.... 
> 
> ----- Original Message ----- 
> From: <xvid-devel-request at xvid.org>
> To: <xvid-devel at xvid.org>
> Sent: Monday, October 19, 2009 6:00 PM
> Subject: Xvid-devel Digest, Vol 81, Issue 5
> 
> 
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>> Today's Topics:
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>>   1. Requirments for ecoding VGA at 60fps (Xu Ruian)
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>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Mon, 19 Oct 2009 11:26:52 +0800
>> From: Xu Ruian <ruian.xu at gmail.com>
>> Subject: [XviD-devel] Requirments for ecoding VGA at 60fps
>> To: xvid-devel at xvid.org
>> Message-ID:
>> <416a1d890910182026w3c7e4bb3x72c7c204980c0953 at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Hi,
>> I'm now working on a project to port XVID to ARM 946(270MHz).
>> The final goal is to encode MPEG-4 video of VGA at 60fps.
>>
>> Did anyone have experience of running XVID on ARM?
>> Is it feasible to achieve such a performance on this chip?
>>
>> -- 
>> Thanks!
>>
>> Yours, Sincerely
>> William Xu
>>
>>
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