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-   -   Edirol V8 Mixer: Poor video ouput quality (https://www.dvinfo.net/forum/wedding-event-videography-techniques/235359-edirol-v8-mixer-poor-video-ouput-quality.html)

Antonie Koen May 14th, 2009 02:07 PM

Edirol V8 Mixer: Poor video ouput quality
 
2 Attachment(s)
We record church meetings on a weekly basis and I was hoping someone here could help me with the following.

We are running 3 x Sony cameras (2x fx1 + 1x V1) into the edirol V8 mixer and from the mixer we run the video signal into a pc where we record. My problem is that the final video that gets recorded to pc have 2 black pillars (one on either side) - see attached thumbnail. On top of that, the final video quality is very poor (colours faded and smear). I tried recording straight to a hdv tape deck from the mixer while cutting out the pc and still had the same results. I checked camera setting and everything is correct. When I capture tapes to the same pc straight from the V1 camera, there are no black pillars on the sides.

We currently use bnc cables (RG59) and the lengths vary from 25 metres to 50 metres.

If someone could please point me in the right direction, I would greatly appreciate it. We want to record straight from the mixer to the pc but because of the quality we have to capture all the tapes from the 3 cameras and edit it afterwards which waste a lot of time. The final video is suppose to be for broadcasting purposes but the current quality issues causes big problems.

I have included 2 pics: the one pic is what gets recorded from the mixer to the pc (black pillars) and the other one without the pillars and with the better quality is captured straight from the camera to the pc.

David Stoneburner May 14th, 2009 03:51 PM

Antonie,
Looking at your system and Eidrol, here's what I think may be happening.
First of all, when you are capturing directly from the cameras to the computer I am assuming that you are using firewire. This will always give you the best quality as it is basically a direct copy of what has been recorded. When you capture from the switcher, I am assuming that it is through an analog to DV converter. Again just guessing. You have a lot of transferring of signals going on, which loses a little quality each time. Digital camera to analog - length of cable can be an issue - analog in processed through the switcher - analog out to a converter - back to digital on the computer. The bars that you are seeing might be because the switcher is expecting a broadcast 720x486 signal and the camera only puts out a DV 720x480 signal. During a normal NTSC broadcast you wouldn't see those bars because of overscan. You only see it on a computer because the computer shows the entire frame. Looking at the stills, I really think it's the way the switcher is processing the video. I would assume that you take the RCA video out into an RCA to BNC adapter, possibly adapting it to the cable with a barrel connection. Then if it's a really long length of cable you are going to have some loss there. Using the S-Video connections will help the signal a little, but I don't remember what length you can make S-Video before it starts to lose quality. There are a lot of reasons, but if you are indeed capturing the tapes with firewire, the analog capture from the switcher will never be as clean. One way to test the cables vs. switcher is to bring the cameras right next to the switcher and then run them once with composite cables and then once with s-video cables. Test your quality and that will help to narrow where the problem is. Good luck.

Shaun Roemich May 14th, 2009 04:51 PM

In addition to what David says, when you capture via firewire from a DV camera, you are capturing YUV component (3 discrete channels comprising video signal) while going through the mixer you are inputing a composite (1 channel of video signal with all luminance and colour info combined) signal into the video mixer. That alone will cause signal degradation.

Antonie Koen May 15th, 2009 02:28 AM

Hi David & Shaun, thanks for your replies.

David, you have summed up our system pretty well. I have compared the composite & bnc cables to one another, but stil have to test the s-video cable. As I mentioned before, we use 25m and 50m cables (bnc), and over these distances the composite did not do very well. From what I read, the max length for s-video cables is 150ft,so maybe I must try the s-video cable with a distribution amplifier (will do test on a shorter s-video cable first).

I have also read somewhere about a balun (?) which converts s-video to a cat5 cable. Does anyone know whether this will be applicable in my situation?

Kind Regards

David Stoneburner May 15th, 2009 07:51 AM

I don't know much about that, but the biggest thing to remember is that every conversion you do will drop quality. I'm not saying that the Edirol is a bad mixer. At work I have been very interested in their HD switcher. I saw it a few years ago at NAB. But, they are also an economical switcher, which can effect quality. I think you just have a lot going on and it's hard to keep the quality with all the different type of connections. I have a Tricaster Pro, that I use for field switching at work. The quality is very good, but I'm hooking up composite BNC from a DVC-200 cameras that have composite BNC out. Plus I can record directly to the harddrive on the system, or output full component to a deck. The TC also has a full proc-amp where I can match cameras and video levels on a waveform. I think there is a company that makes a firewire switcher, Data (something). If quality is a an issue and they have some funds it might be worth looking for. Native DV coming out of the cameras, into a switcher and then back out again should yield better quality. You might want to also take a look online for a software base switchers. I know that there are some out there, but their names escape me at the moment.


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