Analog to DV Conversion Question

[hhb]

Hello, followed the recent thread here about peer to peer for NSV, which reminded me that some folks here understand computer video technology in great depth, which I do not. Am hoping some one can clue me about what's actually going on in the process described below:

Setup
Live, wireless dv transmission to remote sc server via NSVCap
Live audio transmission from mixer to remote sc server via NSVCap

Video
DVmini camcorder A/V out to 5.8 Ghz transmitter via RCA.
Receiver to converter box via RCA
Converter box to wireless laptop via firewire
Firewire stream to NSVCap via software bridge
VP6.1 encoding at 300 kbs/25 FPS
Audio
Audio stream via mixer to NSVCap
Raw AAC encoding at 32 kbs stereo

5.8 wireless dv transmission seems to work well -- inside (through walls, from 1st to 3rd floor, etc) and outside (okay at varying distances so far, transmits cleanly from outside to inside receiver/laptop).

Problem
When dv from remote cam gets to NSVCap, preview is fine, but online display (webpage player and winamp) shows the bottom two pixel lines incorrectly, sometimes black, sometimes slightly gray, sometimes just movement, which makes me think it's an interference problem.

But both 2.4 -- doesn't perform well otherwise either -- and 5.8 transmitting include the same, bottom 2-pixel line result, maybe suggesting it is an interlace prob.

Adding to my confusion about cause, FFDShow/Dscaler filters correct the display entirely, using either of two methods: TomsMoComp deinterlacer with vertical filter, or dscaler temporal noise filter with default setting -- without noticeable image quality loss.

Question
In the above described scenario, can someone tell me what is actually going on? Is the bottom, two pixel line problem simply interference in the wireless dv transmission, or is it an interlacing problem or what? Read (at http://100fps.com/) that both raw DV and analog (RCA to converter box output) are interlaced, tried both filters mentioned above with success, but mostly got confused about what the root of the problem actually is.

As far as I'm concerned, the fewer filters needed, the better, so am looking for an explanation of exactly what is causing the problem in the first place. Thanks for any advice and for any pointers to relevant info.

hhb

[toqer]

Just crop from the bottom using either nsvenc /config or ffdshow.

[hhb]

Thank you for the tip. For some reason, and unfortunately for this situation, cropping the bottom 2-3 pixels lines with NSVCap or with FFDshow has no effect on the display -- the problem pixel lines just "move up" and are still included in a non-filtered video screen display.

Have even tried extreme crops (50 pixels for example) using both methods. Screen is cropped, but still includes the problem 2-pixel lines at bottom.

hhb

[slavas]

***268; what resolution you trying to encode? maybe its not multiple of 16...

[hhb]

Testing at 320 x 240. But your suggestion made me realize that NSVCap stream preview is okay, no problems with the bottom 2 pixel lines there, so maybe encoding is the faulty step -- VP6.1 with 300 KBS target.

On the other hand, without wireless dv signal and its dv to analog then back to dv conversions, straight firewire yields perfect display. Wish I knew more about this, obviously.

Thanks -- hhb

[hhb]

Today, Monday, May 22, 2006, am testing the 5.8 wireless video setup outside from now (about 2 pm EDT) until dark (around 8 pm EDT). Would appreciate anyone who reads this and has a moment to check out the webpage display:

http://plankroadnetstreams.com/pr-radio/webcam/online-survey.php

Audio is just music, no mic commentary today. Video has little content. Different combos of the 8 Jack Russell Terriers who live here (cam shots are views of the dogyard) will be moving around.

When there's time to spare, will man the cam for better content, but the rest of the time, the view will be wide angle with just random terrier crossings. Full sun until about 4 pm EST. After that, a more saturated view in full shade.

The webpage player is the NSV Active X version -- only a 168 KB download. Thanks to any of you who have a moment and are willing to take a look. Am interested in how it comes across, so please feel free to comment, and thank you.

hhb

[john@ROCKNTV1]

i have run in to this my self,with a dual diplay set up.
on my machine i have a setting that allows "OVERSCAN"
for out put to tv... this is where i made the fix

john:)