[mythtv-users] Re: Re: Best video capture resolution for output to TV?

[Allen T. Gilliland IV]

> Good point (if I undersood you correctly =). The bit
> rate
> also has an impact on how much detail is preserved
> during
> compression. In testing I found that given a medium
> res and
> medium bit rate, raising the bitrate improved the
> picture
> quality more than raising the resolution to hit a
> target
> file size.

Actually, the bitrate is exactly what controls the
quality of your recording.  Basically, uncompressed
video = video at max bitrate.  Essentially, when you
compress your videos you can think of it in terms of
compressing each frame individually.  The bitrate
controls how much data or storage space you are
willing to commit to a single second of video.  So if
your bitrate is 3000 kbit/s @ 30 fps, then you are
using 100 kbits per frame.

Resolution is a factor because it affects your bits
per pixel.  So obviously taking 2 images, 480x480 and
720x480 each only allowed 100 kbits (because of the
bitrate you chose) then the smaller image is going to
come out better because it is not compressed as much. 
So when you are choosing your settings you should
consider how many bpp each frame will have, the higher
the better.

Now obviously compression is tricky buisness and there
are many more factors involved, but bitrate/bpp is the
most important variable.

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