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Harri Raisa
12-07-2003, 12:02 PM
Hi,

What is the main reason to use DV-codec 1 or 2. Is there a big difference in reality?

Harri

ScorpioProd
12-07-2003, 06:19 PM
Depends what you are doing with the DV file.

Most applications fully support Type-2 DV files but NOT Type-1 DV files. SO, if you plan on using the file in other programs besides the VT[3], that could be a concern.

Realize that the video is identical in both types of DV files, it's simply a question of whether the audio is DV compressed and interleaved with the video OR a separate uncompressed PCM audio track that's part of the file.

This is important for two reasons:

First it takes more CPU power to uncompress the audio on the fly versus having it already uncompressed. That's why Type-2 is the real standard in most apps.

Second, because Type-1 has the audio interleaved with the video, it can NEVER get out of sync with the video.

Now this would seem very important, but I have personally NEVER seen any other NLEs have problems with this A/V sync during DV capture.

That said, this isn't entirely true with VT[3]...

Even with the latest patches, which fix bugs that caused sync problems in the past, I still sometimes have A/V sync issues with Type-2 DV. (And if I do the identical capture with a Type-2 DV utility, there's no A/V sync problem.)

So, I recommend Type-2 DV for clips only up to 30 minutes.

If you need to capture single clips longer than this (in VT[3]) I would have to recommend Type-1 DV.

If you render out your VT-Edit project to DV when you are done, I recommend Type-2 always, there's no sync problem doing this.

Paul Peterson
12-08-2003, 06:25 AM
Have they worked on improving the Type-1 capture in the last few updates? I remember trying to capture a short 3 minute piece not too long ago and Type-1 was VERY non-synced. Switched to Type-2 and it worked fine.

One question about what you said about long captures with Type 2. I plan to convert my old home SVHS videos to DVD once I get new drives and plan to edit out the hoaky freeze-then-fade-to-new-video transitions that my old 1990 camcorder used. These are your standard 90 minute tapes. Are you saying I'd definately want to use Type-1 format to avoid sync problems - esp after all the mini-edits I'll be doing? I'll be converting the final to MP2 for DVD writing so I won't need to play realtime.

Paul Peterson

ScorpioProd
12-08-2003, 09:57 PM
Patch 2 fixed the major A/V sync issues on ALL types of DV files that was introduced with Patch 1.

As for the purpose you ask, my first choice would be to use an outside DV utility to do the capture as a Type-2 DV.

If you are gonna do the capture thru the VT[3], the only way to be sure of A/V sync is to do it as a Type-1 DV capture (per Andrew).

Personally, I don't always have problems with Type-2 DV captures of long (>30 minute) clips in VT[3], but once I got BURNED last week on a two hour one that I did straight to DVD before I caught the problem, I don't trust it anymore.

Paul Peterson
12-09-2003, 06:23 AM
Thanks for the info and suggestions, ScorpioProd. But I do have a couple follow-up questions.

If I plan to use only VT[3] to do my edits, is there still an advantage to using an outside app to capture to Type2 vs VT[3]'s Type1 capture?

If so, what apps are out there to do this? I don't think anything came with my cheap firewire card. Are there any out there in the freeware realm?

Paul Peterson

johnq
12-09-2003, 09:41 AM
Here is a program you can try for free ($40 to register). It can detect scenes either by the DV data track or by scene content in either DV1 or DV2 format:

www.scenalyzer.com

John

ScorpioProd
12-09-2003, 11:26 AM
Type-1 should be fine if you're just using it just in VT[3], but try it out and see. You may or may not find Type-1 a little more sluggish to work with since it takes more resources to decode it.

I use DVIO from www.toastersupport.com .

Harri Raisa
12-09-2003, 11:05 PM
Thanks,

OK, that's one of those "behind the scenes" things.

I remember using (VT2) Type-2 to capture BetacamSP tapes (35-36min) and had no problems. I'm using Mainconcept DV codec but can that be the sollution?

I need to look something else than DVapp, that's so 80's ;)

Harri

ScorpioProd
12-10-2003, 02:28 PM
The reason why you didn't have a problem with VT[2] doing Type-2 DV capture via the MainConcept DV codec is because you were NOT capturing via firewire. VT[2] did NOT have that ability.

The MainConcept DV codec is hardwired into VT[3], so that's not an issue, that's the best codec around.

The problem is, for some reason, VT[3] honestly does NOT capture Type-2 DV very well in terms of A/V sync. EVERY other Type-2 DV utility or NLE I've used does NOT exhibit this problem, so I have to believe it's something unique in what VT[3] is doing. Newtek insists it's a limitation of Type-2 itself, but my experience proves otherwise.

My latest advice for VT[3] DV use is as follows:

If you are capturing with another program, feel free to use Type-2 DV and it will be fine.

If you are capturing with VT[3], I now recommend using Type-1 only to maintain A/V sync. I haven't found any negatives inside of VT[3] to using Type-1, though as I said it will take a little bit more CPU power.

If you are rendering out of VT[3], I recommend using Type-2 DV since it will NOT have an A/V sync problem being rendered out and it will be universally compatible with other programs.

Harri Raisa
12-11-2003, 10:00 PM
Oh boy,

But I can also use firewire and record from "program out" so I can use any codec I want. Picture is better than YC. Then there should be no sync lost?

Harri

BTW Did you test that 2pixel move thing? Capture using software DV codec and RTV. Put them to Ted. Is DV 2px up? It moves 2px in every generation, in my system.

ScorpioProd
12-12-2003, 08:48 PM
If you mean that your firewire signal will be vertically offset from any analog in to VT[3] of the same signal, yes, that bug has always been there.

Harri Raisa
12-13-2003, 09:29 AM
Firewire captured from Main In and RTV are same and OK. If I render DV clip from that RTV of if I use software DV, it's 2px up. If I re-render it 10x it's 20px up.

Please, test it. Just render any clip from TeD (DV Type 1 or 2) and put that rendered clip next to original in TeD. If You use still image you see right away if rendered clip is up.

My tests result files (photoshop layers):
http://www.dav-tv.com/bug/

Harri

ScorpioProd
12-13-2003, 11:48 AM
Oh... Well, I'm glad to hear that the bug offsetting firewire input relative to analog is fixed, I hadn't noticed that...

As for what you asked, I'll check it out. I've never needed to remix them after rendering, so I've never noticed.

Jim_C
12-13-2003, 01:32 PM
Harri,

I can not reproduce that.
I created some shapes in Aura, captured 3 secs of DV type2 using Aura as prog out, then re-rendered using type 1 and 2 many many times, I'm on the 10th now, and I don't see any shift up.

Jim

Harri Raisa
12-15-2003, 01:25 AM
Thanks,

OK, it must be my PAL system.

Harri

Tom Wood
12-28-2003, 01:26 PM
EDIT: Never mind, found my answer.