[mythtv-users] IVTV Bitrate & Resolution

John Drescher drescherjm at gmail.com
Sun Mar 25 17:10:32 UTC 2007


> >
> Maybe I am totally wrong on this one but I thought that increasing the
> bitrate past a point would mean that you would mostly improve the
> quality of recording the noise since it is a high frequency component
> and when you have a normal lower bitrate ( 720x480 @ 6Mbit/s) you will
> in effect blur out some of this noise.
>
I definitely am wrong on that for two reasons. Noise is not just high
frequency it is across the whole spectrum. And when you compress the
randomness of the noise uses the most bits. I should have remembered
that from my work with mamography and high compression rates.
Basically with telemomagraphy there is a big need to use high
compression rates when sending mamograms and what ends up happening is
the area of film outside the breast ends up getting the most bits
allocated to it (using jpeg) so we worked hard to develop algorithms
to find the skinline so that we could cut this area out and thus get
more of the bits to be used in the area of concern.

John


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