[MEncoder-users] Encodes for slow laptop

Loren Merritt lorenm at u.washington.edu
Tue Jun 10 00:28:59 CEST 2008


On Mon, 9 Jun 2008, RC wrote:

> On Mon, 9 Jun 2008 02:13:21 -0500 (CDT)
> "R.L. Horn" <lists at eastcheap.org> wrote:
>
>> Some popular (and sometimes mandated) frame dimensions just aren't
>> divisible by 16
>
> I haven't ever seen any.  Pretty much every digital video expert knows
> not to do such a stupid thing.

I don't know who designed HDTV, be he must not have been much of an 
expert.

>> (perhaps most notably, 1080/16 = 67.5).
>
> We call it "1080" for various reasons (eg. aspect ratio), but it's
> actually encoded, broadcast, and decoded as 1088... precisely because
> 1080 isn't divisible by 32.

1080 content is often broadcast as 1080, i.e. encoded as 1088 and cropped 
to 1080 at playback time. Yes, it suffers from all the inefficiency 
normally associated with non-mod16 encoding.
And when it is broadcast as 1088 that's even worse: it means they took 
1080 content and padded it with black borders.

--Loren Merritt



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