Audio out of sync using DV Rack?!

[James Binder]

Hello everyone...

I used the DV Rack Demo this weekend to record a business conference to hard disk (via firewire to external hard drive). Fortunately, I also backed up with tape.

The problem is/was this…

From about half way through each segment (one hour or longer); the audio loses its sync.

I recorded over ten hours of conference and on each video “track” within DV Rack, it’s the same story—the audio gradually goes out of sync—so much so that it’s at least a second or so off.

I also checked the raw files via explorer (outside of DV Rack) just to be sure it wasn’t some weirdness from within DV Rack. It was the same there—audio gradually out of sync from about half way through on.

Anyone else experience this? I would appreciate any feedback or thoughts anyone might have.

Thanks in advance.

Here’s the equipment I shot with:

Compaq Presario Laptop - AMD 1.8 GHz
768 ram
Maxtor 300 Gig external hard drive
Canon XL1, Xl1s

[Danny Fye]

I had the same problem when I used DVRack.

I noticed that DVRack defaults to DV type 2. Try DV type 1 and see if that helps.

This was when I used DVRack to capture from tape. When not using tape, then I don't know.

I no longer have DVRack so I can't experiment with it anymore.

Danny Fye

[James Binder]

Thanks Danny -- going to check that out.

Anyone else with other thoughts/insite?

[Rob Lohman]

DV type 1 won't do you much good since it will restrict the file size
to 2 GB (or max 4 GB), which results in 9 and 19 minutes of
recording time.

[Danny Fye]

<<<-- Originally posted by Rob Lohman : DV type 1 won't do you much good since it will restrict the file size
to 2 GB (or max 4 GB), which results in 9 and 19 minutes of
recording time. -->>>

It's not the type of DV that restricts the file size. It's the type of hard drive format used. If one were using FAT/FAT32 then I would have to agree but with NTFS this would not be the case.

I use DV type 1 and NTFS and I don't get the restrictions that you mention.

Danny Fye

[Karl Soule]

Right, there are actually 4 different formats we are talking about - The AVI spec has a 1.0 and a 2.0 file header format, which is where the file size limit comes into play. The majority of programs out there use the 2.0 (OpenDML) AVI header format - the only exception I know of is the export function of an Avid. As far as DV Rack is concerned, all files written by DV Rack use the 2.0 (OpenDML) file header, and don't have the file size limitation mentioned.

Then, there are the different formats for DV data.

DV-AVI Type 1 puts the audio and video into one interleaved stream. It ensures that the audio and video will stay locked together, but some older editing programs will not read these files.

DV-AVI Type 2 store the audio and video in separate streams within the file. This makes it easier for some programs to open the file, but it can cause audio drift.

Unless your editing program specifically requires DV-AVI Type 2, I would recommend recording to the DV-AVI Type 1 format. What type of editing software do you use?

[Danny Fye]

I use Ulead Media Studio Pro 7.2.

I was reffering to DV-AVI type 1 in my earlier posts. Or I should say that is what I meant. Sorry about any confusion that may have caused.

Danny Fye

P.S.

I would get DV Rack but I can only afford the $295.00. I can't dig up enough money for the $495.00 and then wait on the rebate.

So I guess I will have to miss this one. :(

[Rob Lohman]

Thanks for setting me straight. I was mixing up AVI and DV types,
indeed. Doh! AVI type 1 is a filesize limit, DV types not indeed.

[Tim Polster]

Any thought on the original question?

I am thinking of getting this product and will definitely want to stay away if it loses audio sync.

[James Binder]

I think the answer is -- don't record AVI 2 to hard drive if you have very long shots. Up to about 1/2 hour, you're okay. Use DV1 instead.

Thanks everyone...

[Tim Polster]

So if you record with DV1 (which I have never thought about the difference), you can keep sync for as long as you need?

Thanks

[Rob Lohman]

Why not try out the demo and see for yourself? Anyone else who
wants to test this is more then welcome ofcourse!

[Danny Fye]

<<<-- Originally posted by Rob Lohman : Why not try out the demo and see for yourself? Anyone else who
wants to test this is more then welcome ofcourse! -->>>

I just did that with my new note-book computer. So far the initial results are very poor. The longer I capture DV the more components there are that lock-up and no-longer give results. Once I stop the capture, then they all catch up again. Not much help during the capture.

I do not yet know the quality of the capture(s) so I will post the results of that later.

I am getting ready to watch the Stuper-Bowl :) right now so I will update later.

Danny Fye

[Karl Soule]

The problem with audio drift in a DV Type 2 file is a known issue with DV Type 2. It's not a unique problem with DV Rack, but rather a problem with the format. Type 2 DV Files store the audio and video in seperate "streams" within the file, and playback can show audio drift over time. It rarely shows up in clips under half an hour, but 1 hour-2 hour clips like Rob was capturing will start to show the problem.

The fix is simple - use Dv type 1 as your capture format for long captures. Type 1 DV files keep the audio and video in a single "stream," much like the way the data is recorded to tape in the camera. This prevents the two from coming out of sync with one another.

[Danny Fye]

<<<-- Originally posted by Danny Fye
I will update later.

Danny Fye -->>>

Hi all,

Ok, I checked out the video capture and it is real good.

The cause of the problem is I am capturing to the C: drive and when Windows needs to access the swap file it can't because the hard drive is being maxed out to save the DV. Once I stopped the recording it snapped back to normal.

Another problem is that my note-book computer uses an Intel 82852/82855 Graphics controller integrated video that shares 64 meg of memory with the normal ram.

Solution: I connected an external USB hard drive and it works quite well now. The scopes are a little bit choppy and repetitiously so but not to a point of being annoying.

Someone said that the demo will corrupt the file if one captures more than an hour. I did a test capture of an hour and ten minutes (14 plus gig) and had no problems at all. Most of my captures are over an hour.

Mr. Mapes said that DV Rack can be activated on two computers. When I originally bought DV Rack, I didn't know that and the user agreement doesn't indicate this. That is the reason why I didn't just go ahead and activate it on my home-editing computer. I was concerned that if I did that I wouldn't have been able to do so with the Church system.

I am now using the note-book computer for the Church video so no more problems there. I do wish that Serious Magic would update the agreement to indicate that DV Rack can be activated on two computers.

Through my mom (whom I have to pay back) I just ordered DV Rack from BH to take advantage of the price they have.

Question, should I update DV Rack before I activate it?

So, it looks like I will be a DV Rack user after all.

Sorry if I drove everyone crazy with all this stuff. I hope and look forward to a positive future with DV Rack.

Thanks,

Danny Fye