[mythtv] [Patch] small playback bug

michael at optusnet.com.au michael at optusnet.com.au
Mon May 26 09:59:24 EDT 2003

Isaac Richards <ijr at po.cwru.edu> writes:
> On Sunday 25 May 2003 12:04 am, michael at optusnet.com.au wrote:
> > For some reason, the pvr-250 code assumes that the keyframe
> > distribution is different for PAL. The patch below is needed
> > to get the slider bar to display the correct times.
> > (Without this the total length is calculated incorrectly).
> Err, it is different for PAL (check the driver source), the length is not 
> calculated if a seektable exists, and the variable's overwritten with the 
> actual gop size once it's read enough data to detect it.

I've look through the driver source, but real life seems to differ:

[root at localhost driver]# ~/ivtv/ivtv/utils/test_ioctl -t
Standard = 0x000000FF
[root at localhost driver]# ~/ivtv/ivtv/utils/test_ioctl -C |grep framesper
framespergop: 15

If you read the driver source more carefully, you'll note that the
framespergop variable is initialized on module load (before the
standard is set!) and that setting the standard doesn't change
it. (Only changing the codec settings manually via S_CODEC will move

Either way, there's a additional bug: Once the actual gop size is
detected, the time length calculation isn't re-done, so the slider
shows the recording at being (for example) 42 min long instead of 60

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