The VideoLAN Forums

Hiya!

Transcoding from capture devices gets pretty messy results since there is no filtering or deinterlacing of the source signal before VLC starts to crunch it into mp4v or similar. Especially at bitrates below 1000kbit.

Performing a realtively simple deinterlace and/or a noise filter before the transcoding would probably improve picture quality for a small price in latency.

Just my 20c

Does what you're seeking apply for something like the Hauppauge (sp?), where the card is popping out MPEG2-encoded data?
(edited by markfm)

Ahh, I see what you are talking about -- something similar to bringing the DScaler code in, at least as a selectable filter. (don't want to force use of it, but permit, if chosen)

http://sourceforge.net/projects/deinterlace/

Yup, that is pretty much what I want
Though the Dscaler code seems to be hardwired to work only with one capture device which is a shame :/
(edit) wrong of me, they do support several RAW capture cards, not my PVR-350... Blargh.

ffmpeg has a deinterlace parameter. Look for it in the vlc options. You can modify the MRL by hand to add it to the transcoding options.

I return to this old topic:
I didn't understand the MLR comment very well. And I didn't find any good hints on this topic:
for transcoding especially television traffic (DVB-C in my case) it would be very useful to be able to filter it first. I do have lots of codecs and filters for that (FFDShow, DScaler stuff, PureVideo) but I don't know how to enable it in VLC. Ermm.. not before the transcoding-phase!

The tip about using deinterlace option in VLC extented configs is worth checking, but also other kind of smoothing would be worth it for the performance. At an earlier stage I had pretty extensive FFDShow tree for different kinds of signals, and when upscaling (->HD ready or Full HD) the load became unbearable if you didn't have smoothing before upscaling. So it might really save both CPU and bandwidth.

Is there any news on this topic?

(Sorry being such a newbie. I am a picture quality freak and an engineer, but these filter graph trees are just horribly difficult stuff! )

FFDshow doesn't apply to VLC.

FFDShow was just an example. With it you can easily see the effects of different filters in different conditions.

To answer my own post: adding vfilter=deinterlace,postproc,noise to the transcoding sequence, either on command line or the streamin extra options does the trick. I have not yet tested well with ffmpeg filters or how much line capacity this will save. But for others looking for the same info; there are these couple of filters helping even before the transcoding. Makes life much more bearable when streaming out.