[Ffmpeg-devel] Problem with DCT coeffs

[paolo mosna]

Hi all,

I just have a question about DCT coeffs for MPEG1 or MPEG2 files.

FF_DEBUG_DCT_COEFF has been setted.

When I read DCT coeffs from AVFrame->dct_coeff it happens that the first
element
of the array is 0.
But this is the upper left value of 8x8 DCT matrix which represents the DC
component.
This value should not be 0. Having 0 gives me problem when i convert back
the block with inverse DCT.

By the way this happen non only for the first 8x8 DCT block, but for a
medium number of blocks but not for all.

Does anybody know what the reason could be?

Thanks for any suggestion.

-- 
Ing. Paolo Mosna
Senior Software Analyst

Phone: +39 329 7776617
Skype: paolo.mosna
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