[pvrusb2] Jumpy Video in Mythtv

[Mark Goldberg]

On 6/28/07, Mike Isely <isely at isely.net> wrote:
> It is a known fact that if the audio is set to full scale on a PVR USB2
> device then you *will* get distortion.  This is actually what the V4L

> One good way to try to debug the audio issue here is to divide and
> conquer.  Try operating the device just with mplayer, using sysfs for
> the volume control.  Figure out what the right maximum gain is in that
> case.  Note the value.  Now go back to MythTV and get into the state

I've noticed this and my MythTV encoder settings are not at 100% volume.
Looking at the sysfs interface the level is some odd number in the 50000s.
I've reduced this to 48000 and there is still distortion. It is a
little difficult as
some of the MythTV encoder settings are ignored and some used.

I'm thinking though that the level may just be too high for the
hardware input, so
reducing the software volume may not help.

>Though if you are not getting distortion for ATSC playback
>then this would seem to rule out everything downstream of the PVR USB2
>device.

I think they use different audio codecs, so this may not be sure.

It also seems that there still may be a slight audio delay or video
delay, not enough to obviously tell, but enough so you can tell
something is not quite right. Is there any adjustment for this in the
encoding side. I know you can adjust it during playback, but it would
be nice to have it recorded ideally.

Mark