Trevor Bradley wrote: > I've just discovered the magic of the temporal filter on the Hauppauge PVR > cards (see my previous post). In brief, appears to clean up a noisy analog > signal to give a cleaner mpeg recording. However, I note that there appear > to be several other filters. If I run "v4l2-ctl -l | grep filter" on my > machine, I appear to get parameters for: > > > > spatial_filter_mode (0), > > spatial_filter (0) > > spatial_luma_filter_type (1) > > spatial_chroma_filter_type (1) > > temporal_filter_mode (0) > > temporal_filter (8, was 0) > > median_filter_type (0) > > median_luma_filter_minimum (0) > > median_luma_filter_maximum (255) > > median_chroma_filter_minimum (0) > > median_chroma_filter_maximum (255) > > > > the numbers in brackets are my current settings for these parameters. > > > > By simply changing my temporal_filter from 0 to 8, I saw a dramatic > improvement in image quality. This gets me thinking that modifying these > other numbers might be useful, but I've not found any documentation > whatsoever on these filters, and I'm hoping someone might be able to > enlighten me. > > > > Can anyone explain what the ivtv spatial, temporal, and median filter > settings actually do? Are they hardware or software filters? What's the > difference between the filter and the filter type? What settings are > appropriate for a TV? What numbers are too high? (I noticed that a > temporal filter setting of 10 caused mpeg recording errors, and a max > setting of 31 generated some bizarre visual effects). Should this > information be documented in the wiki?
Yes we should put it on the wiki. If there are people who can explain them and have time (usually the problem) lets get these documented. And not limit to just the filters. I would like to recommend starting a new page for v4l2-ctl and link for each option which needs more explanation to a lower more in depth section. > This question belongs in ivtv-users, but the people who would be able to > answer the question are likely lurking in ivtv-devel. Hopefully some of the > developers read both groups. The dev(s) read ivtv-user but are busy writing code. So it would be the more knowledgeable user and google who can drive this. And of course if the dev(s) have time ... :-) > Trevor Bradley > > Surrey, BC. Canada Greets Sander _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
