recording to a laptop?

[Jeff Chandler]

I like the idea that you are going to offer in different versions.
As for the auto-naming, I was thinking like Event 001, Event 002, etc. I have started testing the beta and I like what I see. I'm really glad to see an alternative to DV Rack being developed, particularly since Adobe has aquired Serious Magic.

[Michael Sweeney]

sorry about the last post, i was doing it from my cellphone. this is what i meant.

i hook my camera up to my laptop through firewire.
i open premiere
since i cannot just press record on my camera and trigger record on my laptop under capture i must press record on the laptop after i press record on the camera. this way it is recording to the laptop and the tape in the camera.

now since i had to press the record button seperately on the camera and laptop, the time codes will not match between the files and the tape.

so i edit my film and finish, i delete the capture files to free up space and because i still have the tape to recapture if i need the footage again.

in premiere it has the files as "offline" because it cannot locate them. so i would have to select them and select "batch capture" to re capture the footage from my tape since the files were deleted. but now this is where it worries me. when i went to press record on the camera then on the laptop, they started at a different time. so the "offline" files have the timecode of the files capture when originally recording, not the tape timecode. so when i go to capture off the tape the timing will be off because the laptop and camera cannot start recording at the exact same time.

i hope that makes alittle more sense.

[John Miller]

Originally Posted by Michael Sweeney

so the "offline" files have the timecode of the files capture when originally recording, not the tape timecode. so when i go to capture off the tape the timing will be off because the laptop and camera cannot start recording at the exact same time.

i hope that makes alittle more sense.

I understand now.

I was about to reply that you'd be okay - the timecode going on the tape will be the same as being sent via Firewire for capture.

But...

I thought I'd check and, to my amazement, the timecode on the tape is off by three frames compared to the captured version.

Here's what I did:

Set up my Sony PDX-10 to record to tape
Configure my capture program to capture to disk (our DV processor)
Hit record on the camcorder
A few seconds later, started capture

I pointed the camera at the computer monitor to record the capture program - it displays the timecode so I would have easily identifiable frames to compare later.

Then, opened the captured file in the DV processor - configured it to stamp the timecode on the video
In a second copy of the DV processor, cued up the camcorder with the taped version - again configured to stamp the timecode
Cued both versions to the same timecode and compared the frames

The result - see the attached thumbnail (click to enlarge).

Basically, the timecode recorded to tape is three frames ahead of that send via Firewire for the exact same video frame.

(There's also a latency between the camcorder and the computer. You can tell this because when the timecode written to the camera is 00:00:27;11, the camera sees frame 00:00:27;04 display on the monitor.)

Anyway - I'm surprised. I expect the camcorder is injecting the current timecode into the processed DV stream. The latter will be somewhat behind what's going directly to tape since the way DV is laid out on tape is rather different than the way it is packaged for Firewire. Perhaps it takes about 3 frames for the camcorder's firmware to do that...

There are options to get identical timecode on tape and disk:

1. Capture to disk only and then send back to tape IF you have a device that can preserve the incoming timecode (my Sony DSR-11 deck can do that)
2. Determine the timecode lag - for a given camcorder it's probably constant - and add/subtract in Premiere (you can tell Premiere to offset the timecode for each clip)

(The next version of our processor will have the "Embedded Data Processing" feature implemented and that will allow you to add/subtract values from the timecode etc during capture).

I wonder how different makes and models differ in this regard....

[Michael Sweeney]

well thanks for testing it out, i am trying out the trial of dv rack. i just hate to have to spend that much for a program. ill test out your program as well. i geuss .03 of a sec is not that big of a deal. how long after pressing record on the camera did you wait to press record in the captuer program?

[John Miller]

About 5 seconds or so.

I tried it twice with a different delay.

Both times, I got the same difference in timecode.

BTW, the current version of our software doesn't have the feature yet. It will do (it's a trivial addition).

[David Stoneburner]

John,
I just downloaded your beta to my new laptop. I won't be able to use it till my firewire card comes in. At work, I've been using DVRack for around a year, so I am eager to test your product. My laptop specs are a Turion 64, Win XP pro, 80gig 5400rpm HD and 1 gig of ram. I'll try to give as much feedback as I can.