(no subject) eh? Interesting. :)

On Tue, 2007-05-15 at 16:34 -0700, Lan Barnes wrote:
> This is a race to see where I get the answer first ;-)
> 
> I have seen several variations on this question and suspect it may be more
> than one possible problem.
> 
> I recently upgraded from MythDora 3.2 to 4.0 with a reinstall. I did not
> have this problem in 3.2.
> 
> While watching a baseball game, mostly all was OK, but while watching a
> large thing in motion, like a man running, the white uniform would
> "stretch" along the axis of motion blurring out like a cartoon character
> leaving streaks behind him. The blur looked pixilated and "caught up" when
> the guy stopped.
> 

Without seeing it, it sounds like what I spent two years looking for in
my previous life working with MPEG-2 video compression hardware. I also
see this more than I'd like on nearly every cable and satellite station
on the planet.

The reason this happens in cable and sat. reception is simple, but often
ignored by most folks. It's a result of too much compression at the sat.
uplink (Note: All TV transmissions come via satellite, unless you're
using a TV antenna and licking up local channels). In the quest to make
more money, the providers have compressed the data to the ragged edge,
causing pixelation and macro-blocking (A macro block is a large square
the size of several pixels and often appearing as all one color. They
usually appear in multiples of 4). The compressors I worked on could get
about 270:1 compression with almost no discernible pixelation, which
translates to about 2Mb/second of streaming MPEG-2 video data. After
this point, the pixelation becomes worse and worse, but boy does it save
bandwidth. By compressing the video a bunch, the providers can get more
channels on the sat., thereby making more money off of you and me.

In the early days of digital TV, I found the picture excellent. As time
wore on, I began seeing the crap that I tested for in my previous life
(and when we saw it, we repaired the unit causing it). These days I
rarely see a HDTV picture I like.

So, it could be the compression ratio either at the uplink, the
downlink, or in your Myth setup. If your setup can't handle decoding the
stream, then this will be the result. If something is configured wrong,
this could be the result. If you provider has a screwed up system, this
could be the result.

Since you indicate things were OK before the update, I'd lean toward
something being amiss with the newer version of MythDora (as opposed to
a problem caused by your provider, receiver, or computer).

PGA  
-- 
Paul G. Allen BSIT/SE
Owner/Sr. Engineer
Random Logic Consulting
www.randomlogic.com


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