[FFmpeg-devel] DV Video and SAR

[Baptiste Coudurier]

On 10/19/2009 11:01 AM, Charles Yates wrote:
> 2009/10/18 Baptiste Coudurier<baptiste.coudurier at gmail.com>
>
>> Thanks, applied.
>
>
> Much appreciated :-).
>
>
>>
>> This one looks ok as well. I'll apply it soon I think.
>>
>
> Good - thank you.
>
>
>>
>> I was wondering if we shouldn't set sar for dv to digital sar as opposed to
>> analog sar considering mpeg-2 sar and how FFmpeg deals with sar in general.
>> Any opinion ?
>>
>
> I am not sure what you mean there - to the best of my knowledge, the SAR's
> reported for DV and mpeg2 are (pretty much) spot on.
>
> I'll stick to 'pretty much', cos all the SD values are approximations anyway
> - ie: 720 * 59 / 54 != 788 (should have that, thus leaviing 10 samples on
> left and right which is the overscan and the central 768x576 being the true
> 4:3 image) - but I think they were chosen to be uniformly expressed as a
> pair of bytes or some similar olde worlde consideration? Is that the issue
> you were referring to?

Well, the values DV SD currently uses do not follow the rule 
width/height == dar/sar (DV HD does). I think this is because DV doesn't 
use the same production aperture.

MPEG-2 does follow the rule however.

[...]

-- 
Baptiste COUDURIER
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