[vdr] Re: Interlacing

[Lucian Muresan <lucianm@users.sourceforge.net>]

Nicolas Huillard wrote:
> Live TV on some channels is still very jerky (rendering speed is much 
> lower than normal, and there is a time-compression each few seconds to 
> compensation), but I don't watch much live TV.
> Recordings sound has clicks, and sound like if there was constant 
> resampling. This is particulairly awful when playing music, where the 
> beat is not at all regular. I still have to provide sample recordings, 
> but I need first to make sure this is not related to my setup (sound 
> artifacts are not the same when I change the fb.modes timings and TV 
> output config of the vt1622 chip (tied to the cle266)...
Yes, I also noticed such differences on different channels. I also had 
lots of clicks when I first tried softdevice, but that was 2 versions 
before I think, and with vdr-1.3.11 I think. Currently, maybe due to 
latest optimizations in vdr-1.3.14, I don't hear any clicks. Only the 
video seems to lag behind when the OSD is displayed, when the OSD goes 
away, video visibly "accellerates" and catches up to almost lip-sync. 
And I do not have a too powerful CPU, just a old Duron@1000MHz, and the 
usage is around 55-60% without OSD and deinterlacing turned off (I 
shouldn't need it on TV, but there is still this field-parity issue...), 
and up to 80% whith an OSD and I don't remember what it was with 
deinterlacing turned on. And all this with both video and OSD on the 
same DFB layer, as the sub-pictere layer doesn't work yet with softdevice.

In fact, I'm using a regular cheap FTA receiver for live zapping, and 
also want to use VDR mostly for recordings, and in the near future 
controlled from Freevo, as I don't see any point to use plugins that 
re-encode videos and pictures as still MPEGS from different formats to 
MPEG when using a budget card, where the CPU is doing the decoding, too...

> I didn't look at the latest softdevice yet, but what you describe make 
> me think the dithering does the stuff (this fits the description Torgeir 
> gave). I didn't ever have transparent OSD (grey background is fully 
> transparent, and colors are opaque).
Yes, I think you must be right, it should be due to Torgeirs dithering 
idea, it only looks much better on TV than on the old monitor I used to 
drag to the living room right down on the carpet near the htpc, you 
could say the grey areas are truly transparent on the TV, but colors are 
opaque, indeed :-)

> Everything is supposed to be transparent. I had it with softmpeg when I 
> did experiment with it.
Softmpeg is really unusable now, right? I can't even compile it with the 
current DirectFB, DFB++ and FusionSound CVS versions, I would have loved 
to see it in action, too...

> I am also happy with it, but on some channels. Others are awful on live 
> TV, and recordings are not the best (naturally, those are the ones I am 
> most inclined to watch). I'll come back with samples when I dig into a 
> code much more than I did.
I don't know too much about DFB yet, but I'd love to help improving DFB 
output. Now I'm trying to understand the DFB architecture, as I even 
need to implement a video signal switching feature for DFB output (my 
G400 TV-out RGB to SCART cable is looped through the sat receiver and 
switching to RGB-mode is the only way I can get the picture from the 
HTPC on the TV, but sometimes I want to be able to see the signal from 
the sat receiver, or the TV's analogue tuner itself, and that's only 
possible if softdevice would switch back to composite signal). Maybe you 
guessed already, my TV has only one single SCART connector and I don't 
want to plug/unplug cables, but just use a RC button to switch output 
signal format...

Lucian