[LINK] Does NBN need a third satellite?

Jim Birch planetjim at gmail.com
Mon Apr 4 13:31:07 AEST 2016


On 2 April 2016 at 13:54, Karl Auer wrote:

"compressed for transmission" means "has had much data discarded".


All digital video is compressed, except maybe the truly lossless "raw"
digital masters at a studio.  These chew up massive bandwidth/storage, and,
contain a lot more information than the human eye can see. Forget it. There
is actually no benefit to the end viewer in using this stuff, it's a
massive waste of resources.

There are two main problems with video compression: overcompression and
poorly optimised compression.  In practice there is a grey dividing line.
Increasing grunt applied to the compression process can produce a vastly
better result with the same bit rate.  Crappy compression is more or less
artlessly mash the "raw" video into to available bandwidth via dropped
frames and pixelation.   This is why Netflix look so great compared to some
crappy youtube video: they might both have the same nominal resolution and
bit rate but Netflix really grind the best possible result out of the
bandwidth. (Netflix do engage in some other dirty tricks like cropping
scenes.)

In this context "compressed for transmission" doesn't mean compressed,
every one does that.  It really means "Sorry mate, we know this has
problems.  We're pushing the bandwidth line and maybe could be doing
smarter compression, and yes, you can see it."



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