Tim Wassink wrote: > Hi Stuart, > > Thanks for the detailed reply. > > What I do is: ... > 3. MVPMC: connect via a playlist to the mpeg2 stream of the linux machine. > I see the shadows around the text. ... > The shadows are also around the text of the menu. From this I made a > photo, and this is the picture I linked to in the first mail.
So, the only times you see the shadows is when you are looking at video from an MVPMC box over a SCART cable on your TV. > I've captured with mvpmc pressing the green button. It is a picture > without any shadows. > But it's unclear to me when this screen shot is generated. But it's > probably taken before the "TV signal generation logic" of the mvp. The screen shot is generated digitally inside the MVPMC box. It's after the image has been decoded (by hardware in the IBM / PowerPC chip) but before it is sent to the TV. > The shadow appears on a normal tv as well as on a plasma tv (both > connected to different mvp's). > The scart cable is 2m long (the included one, as well as the goldplated, > with foil one) > You mention termination is bad, could you tell me what I can do about this? Well, it sounds like you already did the 1st thing I would to. You tried different sources (i.e. different MPVMC boxes) and terminations (i.e. different TVs). I don't know what SCART terminations are suppose to be. In the states everything should have a 75 ohm impedance. One last thing, did you swap the MVPMC boxes between the two TVs? Ok, I checked the wikipedia. It looks like a SCART cable can transport several different signals. I don't know how it should work, but if you can check, see if you can switch between them. I would avoid composite signals and try for either s-video or component (R, G & B) signals. So, does anyone else with a SCART setup (kit) have this problem? It does sound like a termination problem and not an artifact of MPEG decoding. > Already many thanks. > > Best regards, > > Tim > > On 1/10/07, *stuart* <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote: > > Hi Tim... > > I don't mean to doubt you, but is this really a screen capture or a > picture taken with a camera of your TV? It just looks a lot like a > signal reflection from bad terminations or delayed response of some old > picture tube. Further, and I'll be the first to say I am not entirely > sure about this, MPEG encoding artifacts should be distributed *around* > objects. That is before, below, above & after a sudden change in the > encoded picture. Your image shows artifacts to the right of the > picture. If you did take the picture using a camera - try using the > green button on the MediaMVP's remote control while running just about > anything other than MClient. You will need to use the proper option on > the mvpmc command line (in your dongle configuration file) to indicate > where to save the screen capture. This method would eliminate any > problem with your video cable or TV. My guess is that your cables are > fine, but you have bad termination. If the impedance of the cable, the > source of the video and the destination of the video do not match - the > signal will bounce back and forth between the ends of the cable. The > longer the cable, the longer the delay and the artifact or "reflection" > of the images will appear further to the right (TVs scan from left to > right). > > Given the above, let's see, SCART - so your picture is being refreshed > 50 times/second. Horizontal scan is about 15KHz. There might have been > 40 chars across the screen. The echo looks like 1/4 of that. About 30% > of the Horizontal scan is wasted in blank screen and synchronization > pulses. So [(1/15K)/[(1/.3)*40]]*(1/4)=125E-9 seconds. Light is > 3E8m/s. So 3E8*125E-9=37meters. Hum, that sounds long. Are you using > a 37 meter SCART cable??? Well, there's a lot of guessing going on > here. For instance signals do not travel at the speed of light through > a cable - it slower - which would make the calculated cable length > shorter. And if these characters were smaller than I am guessing (like > say you could fit 80 across the screen) that would just about half the > calculated cable length. > > > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Mvpmc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mvpmc-users mvpmc wiki: http://mvpmc.wikispaces.com/
