I'm running Zoneminder 1.28.1 on slackware 14.1. No video will display on the cameras connected to the DVR card. /dev/video0 to /dev/video3 all give the same error.

It's a Techwell TW6816 8 channel DVR card. The IP cameras work find but this card doesn't with Zoneminder.

I'm able to output the video to a file using ffmepg.

I tried lsof and all video outputs return nothing.

For some reason Zoneminder thinks the DVR card is busy but everything else can use it without a problem.

Not sure what to do from this point.

Any help will be appreciated.

I was hoping someone who was familiar with the specific hardware you're using, or your specific error message might have responded by now. Since they haven't, the one thing I can tell you is that I've seen a variety of seemingly strange issues with ZoneMinder resolved by "playing" with device access permissions and such. I realize that's rather vague, but when I've been involved in resolving issues with ZoneMinder, things seemed vague! To me, even the current ZoneMinder documentation seems a bit vague, or in the case of a number of pages, just plain missing. I've talked to other people I know who have been involved in overcoming strange issues with ZoneMinder and they seem to have a similar feeling about ZoneMinder issues; adjust device access permissions, perhaps device ownership, and the issues were somehow resolved once ZoneMinder was happy with those things.

I've spent a couple of weeks on this problem and all I have come up with is that there is a problem with the new tw68 driver in the 4.X kernels or with zoneminder's ability to talk to that driver. I've done all I can do with permissions in an attempt to gain access. Every other program including ffmpeg can stream video from that card but only zoneminder has a problem with it. I've noticed that several others have the same problem on the ZM forums.

So at this point I'll just have to replace the card with IP cameras since they seem to still work.

Thanks for the reply.