[mythtv-users] DVB questions

[Jesper Sörensen]

jason bright wrote:

>If I go into the system settings and to the recording profiles and go
>to the DVB capture card, there are a pile of options - image size,
>codec (RTJpeg, MPEG4, etc), quality settings, etc etc.
>
>Now correct me if i'm wrong, but isn't the DVB card supposed to just
>capture the raw MPEG transmission stream. So - why do we have these
>options? Do these parameters actually do anything?
>

The recording profiles aren't used for DVB. As you say, with DVB it just 
saves the raw MPEG stream.

>To describe the problem - the output image just doesn't look as clean
>as I remember using a dedicated DVB STB. I don't have one on hand to
>compare directly but i'm going to borrow one for some tests. For
>something like a newscast where the background is a reasonably
>constant solid color there is quite a bit of jitter and crawling and
>what looks like jpeg-y compression artifacts.  2001:A Space Odyssey
>was on the other night and the black monolith around Jupiter looked a
>real mess.
>  
>

I believe there is a denoise filter in Myth, maybe you could try using 
that? Or play with the brightness/contrast and other settings for the 
channel. Try playing a recording in mplayer or xine and see if there is 
a difference? (Although I think they all use ffmpeg/libmpeg2 so they 
should be very similar).