Analog to Digital Video Converter crapping out

[ScottL]

I have an interesting live video streaming set up involving an underwater camera. The camera is powered from one end of a shack on a pier and the analog out runs into an analog to digital converter which then runs into a macmini. The macmini sends the video to an external site that handles our streams. I keep on having problems with the converter crapping out (no longer transmitting the video to the mac) I have tried two converters from ADS and one from Grass Valley (ADVC-110). The ADS converters started with some banding, red at first which then turned to black ie no video. I replaced the DC converter and it worked fine for a few days then went down all together and stopped transmitting anything. I have the ADVC-110 out there now which is working ok. However, I have been having a video quality issue where the image becomes murky and pixelated. I then close quicktime broadcaster (how the image comes back from the external site) and reopen it and the video is back to prime quality. Could the converter be causing the sometimes 4 to 5 times a day decrease in quality? Thanks

[lordsmurf]

I don't know that either of those devices have long-term stream feeds in mind. This is generally where you have to move on to more advanced products made for such a use. I read about quite a few streaming products regularly, in magazines like Videographer, DV and Broadcast Engineering.

[edDV]

Cable distances are important. So how long is the Firewire cable from ADVC to the MAC Mini? Then how does the Mac Mini connect to the telco for upload?

What is the environment for this equipment? (e.g. temp, power conditions, moisture)

[ScottL]

The firewire is short, about a foot and the mini and ADVC are right next to each other. The mac mini is connected through CAT5 to the internet hub also located on the pier with the camera. All the electrical equipment (the ADVC mac mini and internet) are located in a temperature and humidity controlled room kept at around 80degrees. The power for the camera is not in a controlled room. However the camera goes into a splitter where we then RF the image back to our laboratory for a display we have here. Out of the splitter an analog cable runs to the ADVC. The image RF'ed to the lab is very clear and has no problems so it must be past the splitter where the problem is. If the problem is just that our ADVC is low quality does anyone have any brand or model suggestions? The longest cable btw is the cable from the splitter to the ADVC that runs about 20-25ft. Thanks for the help.

[redwudz]

I think the first thing I would do is temporarily take the splitter out of the loop and hook the camera directly to the A>D converter. I would also temporarily try a new cable from the splitter connection to the A>D converter. If all that fails, then maybe the A>D converter is the problem. Or further up the line. Maybe the FW connection at the computer or the FW card.

[edDV]

Yes, everything in that description sounds proper except the splitter. Does the camera output composite NTSC or PAL? Or S-Video?

Please give more info on the splitter. Ideally you would use a distribution amplifier to split video. These are available for composite, S-Video or component YPbPr.

[ScottL]

The video is NTSC. It is a distribution amplifier. We think that any issue is at the ADVC to macmini to internet connections. Our new ADVC is working well for now but the video quality does decrease at least once a day and I have to reset the broadcast. My theory is that the internet connection is slow and we have to clear the channel. When the quality decreases the video drops to 100-200kb/s. At optimal quality it is broadcasting at 400-450kb/s.

[redwudz]

You should be able to find a program that can periodically check your connection speed and plot it out. Not sure of one at present, but others here may have some ideas. At least you may be able to rule out the internet connection as the problem.

There may also be some settings in your computer network adapter card that you can use to improve and stabilize the connection speed.