On Sat, 23 Mar 2002, Gert Vervoort wrote: Gert Vervoort wrote: >> > 2. S-Video input gives a grainy picture with the saa7134-0.1.5/2.4.19-pre4 >> config. This does not occur with the saa7134-mar11-snap/2.4.19-pre3ac3. >> What I mean by grainy is that the color intensity seems to be >> modulating along the scan line. >> >There is a change in 0.1.5 which disables the luminance comb filter for S-video >input, >but this should actually fix the problems you are describing and not causing >them. >I tested this change and this made a big visual improvement (which I did not >expect to be big) >on my board for both PAL and NTSC. > I backported the luma stuff from saa7134-0.1.5 to the March 11 snapshot, and my S-Video input is much cleaner compared to the unmodified Mar 11 snapshot. Also, I don't experience the brightness pumping problem that Gunther described. In the saa7134-0.1.5 module, S-video seems to be grainy all the time. (I haven't tried the xawtv pgup/pgdown trick yet). I believe that your patch works, just that saa7134-0.1.5 has some other interactions. > >What happens if you press pgup or pgdown in xawtv while looking at S-video? >I briefly tested the change of Gerd last wednesday and I noticed that sometimes >I had >to press pgup or pgdown (channels swithing) for the change to have effect. I've >not yet >given Gerd feedback about this, as I did not have the time to have look at this >if this >was a real problem because I was on a course for 2 days. I will check this on >monday. I haven't tried this on the saa7134-0.1.5 module yet as I'm at work (my FV2K is in my home machine). However, I do observe that on my backported March 11 snapshot, video degradation sometimes (~10%) occur when I switch to S-Video. Seems like the IC programming didn't take properly. >What happens if you temporary disble this change?: > >--- saa7134-video.c.1 Sat Mar 23 10:46:41 2002 >+++ saa7134-video.c Sat Mar 23 10:52:54 2002 >@@ -429,8 +429,10 @@ > > mux = card_in(dev,dev->ctl_input).vmux; > luma_control = norm->luma_control; >+#if 0 > if (mux > 5) > luma_control |= 0x80; /* svideo */ >+#endif > > /* setup video decoder */ > saa_writeb(SAA7134_INCR_DELAY, 0x08); I'll try that later and see if it degrades on my backported March 11 snapshot. >> + vmux: 8, > >What happens if you change the input mode (vmux) for S-Video from 8 to 6? > >mode 6: Y channel with automatic gain control, C channel with fix gain (GAI2). >mode 8: Y channel with automatic gain control, C channel linked to Y-channel. On my backported March 11 snapshot, using mode 6 gives a grainy (degraded) signal, while mode 8 works fine. Gert, would you be able to list the various Video modes available on the saa7134/0? I'm not sure which is the appropriate mode to use other than by trial and error. Would different TV norms have an effect on which mode is suitable? So far, I have: Mode Input ---- ----- 0 B/W for S-Video in (Composite over S-Video Input, according to Gunther) 1 TV Tuner video signal (proper video signal) 2 Inverted signal from S-Video ??? (similar to a film negative, but not stable) 3 Composite Video Signal In (proper video signal) 4 ??? (static only) 5 ??? 6 S-Video (grainy / modulated video signal) 7 ??? 8 S-Video (proper video signal) ?? ??? Regards, T.C. ---- Wan Tat Chee (Lecturer) School of Computer Science, Univ. Science Malaysia, 11800 Minden, Penang, Malaysia. Ofc Ph: +604 657-7888 x 3617 Internet: tcwan@xxxxxxxxx Web: http://nrg.cs.usm.my/~tcwan GPG Key : http://nrg.cs.usm.my/~tcwan/tcw_gpg.asc F'print : FB0F CED7 85A5 ECF9 DEF0 50E8 A550 A0D2 8638 B1EB
