Brightness issues and screen jitter

[davo]

Hi everyone. Been occasionally reading the forums and have installed ZM 0.9.15 on RH9 a few months ago. I have only played with it a few times. Zoneminder is a brilliant app!!!

Anyway, I'm using an unbranded four input capture card I got off ebay. I can monitor all four inputs at once, using a mixture of colour and b&w cameras, although I can't set ZM to colour, and only 352x288 res - colour works in xawtv, but only b&w in ZM (I'll sort this out some other time though - might be I have to increase the shared memory).

The main problem I want to fix is this: when I monitor only a single input (disable other three inputs), I can get 25 fps at good quality resolution and good contrast. When I enable more than one input, the frame rate decreases (which I expected), but also the brightness on all of the inputs increases. I have to decrease the brightness using the ZM controls, but the resulting images have lower quality. Also, each input screen has a little jitter - it seems to be jumping up and down on successive frames by a few lines - not too bad, but annoying none the less.

Has anyone else had these problems using multi-input cards? Are these problems created when switching the bt878 chip between inputs? Any suggestions for solutions?


David.

[fernando]

thats is a cuz you enable all bt878 ports and dont put the cameras... you have to create a 75 ohm resistanse on each port ... if not the chip trie to compensate with the other ports "mux" and the only signal you have will get white..