Jarle Bjørgeengen wrote:
Hello,
I have a rather strange ( I think) problem with a TT C1500 card I just
bought.
When watching tv directly with
1 MythTV -> Watch TV
2 xine dvb://
3 dvbstream -ps | mplayer -
, all these methods of watching DVB directly gives a LOT of artifacts in
picture and sound. (blocking mostly.)
_But_ if i do dvbstream -ps > file.mpeg , and then mplayer or xine to
play the file there is _no_ artifacts. This goes for both encrypted and
non-encrypted channels . (CommonInterface and Conax CAM is intialized
and seems to be working with my program card. . )
I even tried both knoppmyth and Mythdora (newest versions as of april
2007), end both have the same problem.
Does anyone have a clue what could cause such behavior ?
Do you by any change have an NVIDIA graphics card?
I had a similar problem a while ago with my HVR3000 DVB-S card.
Recording to disk worked fine. But try to record and watch at the same
time caused artifacts.
I managed to track this down to two things.
Firstly if I used the NVIDIA binary drivers, I had this problem, but if
I used the "nv" driver I didn't. For me using the nv driver wasn't
really an option (MythTV menus were horribly slow)
Eventually I re-aligned my sat dish to get better reception and the
problem went away even with the NVIDIA drivers.
So it seems that somehow the NVIDIA graphics drivers were causing
interferrence with the DVB-S capture card.
A few things you can try to see if the problem is the same :
1) Start a recording to disk, wait for 10 seconds, then start playing
back that file. See if the first 10 seconds of the recording are
artifact free, and then artifacts start after 10 seconds have passed
(when you started using the graphics)
2) Switch to the nv driver (if you using nvidia) and see if the problem
goes away.
3) Start a recording to disk, and play back an entirely different
recording - see if you get artifacts.
4) Check the quality output of szap (or whatever) and see if there is an
increased BER, or drop off in signal quality while playing back video.
Basically though, I never solved the problem of intereferrence, but
since I improved my signal the effects don't have a detrimental effect
on the recording. I think it's still the case that if the video card is
busy then I get a slightly worse signal quality, but it's still "good
enough" to not matter.
Robert.
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