Neuros Technology Forums

Hi all,

I've been experimenting with using my r2 connected to a PAL camera with composite video out: http://www.dogcamsport.co.uk/dogcampro480.htm (http://www.dogcamsport.co.uk/dogcampro480.htm).

Workflow is fine - it just connects up and works - but image quality is not. There are evenly, closely, spaced stationary vertical stripes all the way across the image. These stripes are present even in the preview window, so do not appear to be an artefact of the compression applied (I use 640x480 superfine), but of the actual composite input. Sample frame attached.

Using the same camera connected to my computer using a Pinnacle DVC-90 (I think) USB2 capture card, there are no vertical stripes - the image is perfect quality.

I'm running latest firmware (2.0.22).

Any ideas what the problem is here? ... and, most importantly, how to fix it?

Hi gallafent,

We had the same type of problem.
Since you have camcorders, try replacing the AV cables on the R2.
They are the same as a camcorder AV cable. If it not the input AV cable, the connector may have a cold solder joint.

This is what caused our problem in a racecar.

Well, I bought a new AV cable at Maplin yesterday evening on my way home, then tried it out when I got home. Same problem. I'm going to try another source device or two (I don't actually have any other devices which produce composite output (!), but a friend does) tomorrow.

If that exhibits the same problem, then I guess the r2 may be faulty in the way you suggest (which would be a shame - it's brand new) ..... otherwise, there must be some odd interaction between the two. I'll report back once I've done some more testing.

Just out of interest, do you get the same problem when using the mains adaptor instead of the bike supply ?.

Yes, the stripes have been there since the first time I rigged it up in my study with mains supply. No difference.

Just to update, the recorder records a nice clean signal when I use an alternative input source.

So, the problem seems to be a weird incompatibility between this camera and the recorder, since both work nicely with other components (camera OK with pinnacle capture card, recorder OK with alternative video input) ..... suggestions still welcome!

In  the digital photo arena, these stripes might be referred to as a moire pattern. However, in this case I believe the recorder is hooked up in an undesirable way. It appears to be recording its own output rather than the source.

Mine puts horizontal stripes in the "pass through" video, but it's barely noticeable. The actual recording is clean.

Bud

Er, in what way is it "recording its own output rather than the source"?

The source is the camera, and the recorded image corresponds to what the camera was pointing at. Recording its own output would surely require physically connecting the output to the input.

Hmmm....I have the same type problem in that I get faint horizontal scan lines when the recorder is hooked up, during playback, and simply while passing live video. I wonder if it's an electrical problem or the recorder itself.

I just assumed that the recorder cuts down the signal by dropping some scan lines to make it easier for the cpu to record. But my situation is still passable for viewing.

Bud

Another straw to clutch at...

Interference in the form of banding that moves in any direction can probably be attributed to a problem with the quality of the video signal. Composite video is comprised of a complex waveform that includes the video information as well as various synchronisation signals. If there is a problem in the way the camera constructs the video output then the receiving device (R2) may not be able to reconstruct the waveform sufficiently accurately.

Also there is the possibility of ground loops in the signal path. The video output from the camera is signal+ground which is connected to the R2. The video ground in the R2 is probably connected between the input and output. Finally the TV also uses a ground connection. So there are 3 devices all connected by a ground wire and each has a power supply. If each supply is totally isolated then there will not be a problem however this is unlikely to be so you can get an interaction that appears as interference.

The ground loop problem is quite common on hifi equipment and many units will have an earth tag that should be connected from each device to a common point and then to a suitable earth.

You could try powering the camera from a 12v battery which will show if the ac adaptor is at fault. Also try moving the ac adaptor to a socket next to the R2 supply.

Anyway these are just thoughts, cannot think of much else.

Agreed, ground loop could be the culprit. Gallafent, let us know if you can confirm this or not.