[mythtv] Capture Card Resolution -- was: Re: [mythtv-users] 2Capture card questions

Edward Wildgoose Edward.Wildgoose at FRMHedge.com
Fri Mar 21 09:39:18 EST 2003

> If you, or anyone with PAL could volunteer to help, please update
> to the current CVS and test recording at 768x576 (or 768x288 to
> save CPU cycles). In looking at the bt878 specs (as opposed to
> vague recollections ;-), the chip should allow PAL widths up
> to 768. However, there is at least one reference to 720x576 in
> libavcodec so I'm not sure recording will work at this width
> even if it is supported by the chip.
> Please report the maximum width that does work so that we
> don't suggest a width on the setup page that would fail.
> If no one responds, I'll set it back to 720.

I have tested with 786 and it DOES seem to do something.  I don't know how to check that it really IS recording at 768 though, however, I get video out of the thing (although it skips on my machine).  Quality is noticably higher than 640x480 actually.

I did a quick fgrep on the code, and there is also a suspicious possible bug in the nuvrecord.cpp file.  In several places it checks for video being PAL and chooses an appropriate 640x480 or 768x576.  However, there is a line which appears to be scaling bits/sec (something like "scale = (h * w) / (640x480);" and this I assume is not quite correct on PAL sets? (I guess it is going to be 44% out?)

[sorry I am doing this from memory.  PC is at home]

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