Capturing DV - the same quality AVI from all applications?

[rkelley]

Sorry if this is a silly question (or has been answered before), but...

I was wondering if capturing footage via DV/Firewire would produce the same quality for all applications using the same DV driver? For example, will capturing footage in MS Windows Movie Maker (using the DV driver) produce the same quality AVI file as capturing the same footage via Premiere? I like the ease-of-use of MS Windows Movie Maker when capturing the footage (mainly, because the capture timer works and Premier's capture timer does not work with my DAC-100).

Since all applications use the same DV driver, I would think the AVI files would be the same. However, I have read many articles about audio/video synch problems when capturing footage using different tools.

Thanks...

-rkelley

[jsnkc]

True that they all use the same driver, but the diffrent codecs is the problem, and that leads to video that you capture in one program not as good as the video you capture in another program. For example if you capture something in a pinncale or ulead program, then go and capture that same clip in Vegas video, the one in Vegas video will look a lot better since it is a professional editing software and uses it's own codecs.

[rkelley]

Jason,

Thanks for the info. So, I understand you correctly, I will get a better AVI file from Vegas than MS Movie Maker because the DV codec used by Vegas is better than MS? Even if I select the standard DV/AVI driver?

This is really good info for me. I am trying to convert some VHS tapes for my son and want to get the best possible quality during the conversion process.

Thanks again,

-rkelley

[donpedro]

rkelley, I am not sure how it works, but jsnkc is advertising Vegas whenever he posts.... So I don't know

My understanding was that capturing in DV is lossless and you are capturing data as they are on tape. No conversion, no different codecs.... Of course you can capture in some codec that will let you tweak some parameters, but that you are doing some kind of conversion, modification of original data stream. Again, I never studied this and all what I am saying is what I was told by others on this site, so I might be wrong.

[ktnwin]

When capturing DV via Firewire, the DigCam already compressed raw video into DV format (5:1 ratio), all the capturing software does is copy that data on the hard drive, therefore there should be no difference in AVI quality, UNLESS you tell the capture software to encode into a different format (other than DV).

[donpedro]

I am trying to do some research on this and I will post what I found as time goes.... For now.... Only difference that I found so far is how each DV Camcorder company encode data on tape. So that is why some companies are better that others....

Here is som text that so far proves that software should not make difference.

SNR is not applicable in digital dubs between any of the three formats, assuming the digital data format doesn't change during the process. Using DV-over-IEEE-1394 (FireWire) to make dubs creates a clone of the original DV footage. (The audio data, however, may be bumped from 12-bit to 16-bit or from unlocked to locked in the process.) Similarly, transferring DV footage to a fixed disk using an IEEE-1394 adapter card and then recording back to DV results in a clone of the original content. No decompression or recompression of the DV data is involved in the tape -> disk -> tape process. Neither is SNR a factor in adding transitions, titles, or graphics. Conversion of 24-bit RGB graphics to the DV format, and vice versa, is a mathematical manipulation with a predefined and predictable outcome.

[donpedro]

IEEE-1394 (FireWire) digital I/O gives a dramatic boost to DV's performance/cost ratio for non-linear editing. FireWire I/O eliminates the analog-to-digital conversion (ADC) process of M-JPEG video capture cards and doesn't require ADC for audio inputs. The $999 DPS Spark ($699 without the full version of Premiere 4.2) is priced competitively with low-end M-JPEG capture cards. The Spark approach creates a hard-drive clone of the DV source data with headers added to accommodate Video for Windows' AVI file format. (Codecs aren't involved in DV tape-to-disk or disk-to-tape transfers.)

[donpedro]

Now this link is best....

http://www.dvcentral.org/stepby.html

Just couple of quotes....

DV data, not video, is transferred electronically via the firewire to the computer's hard disk. This not a capture process. it's a file copy process.

During the copy process, the DV data is "wrapped" into a file format commonly understood by computers, in this case either AVI for Video for Windows or Quicktime for the Mac.

But during the file copy process, this codec is not needed.

After the copy process has been finished, the DV data is sitting on your hard drive, wrapped into a file format any standard editing application can process. Note: The actual DV data has not changed. It hasn't been touched by a codec, it hasn't been recompressed, changed or altered.

Clips without filters or transitions are not being touched by the codec and simply copied to the target file. If you would have a project which consists only of hard cuts, the codec wouldn't be called for editing at all.

[JIM E]

So is DV really a lossless codec?

[donpedro]

So is DV really a lossless codec?

Yes if you are transfering from DV camcorder. Encoding was already done in camcorder.

[racer-x]

One difference is, the captured AVI in MS Movie Maker and Ulead (along with others I'm sure) are AVI type-1 @ 3.45 mbts. The captured AVI from Premiere is AVI type-2 @ 3.62 mbts.

Type 2 uses seperate video and audio streams. Type 1 combines them. Type 2 is slightly less compressed than type1.

If you import type 1 AVI into premiere, it will report it as 360x240 instead of 720x480. If you convert type 1 to type 2, then import to Premeire, it will report 720x480.

For the record I do all captures in Premiere. I then edit in either Premeire or ulead depending on what I want to do.

[donpedro]

I was just looking into Ulead VideoStudio 7 and discovered that you can choose which type it will capture into. Type-1 or Type-2. By the way... Pinnacle Studio is using Type-2.

[racer-x]

donpedro;

I use Ulead Media Studio Pro 6.5 and although it works with type 1 or type 2, it will only capture in type 1. They must have changed that in version 7.
If thats the case than I would use type 2 for all captures.

[donpedro]

I forgot important part of product name in original post (fixed it already). It is in Trial version of Ulead VideoStudio 7.

[energy80s]

I don't think it matters which codec is used for original capture of DV footage, it's when you render edited material that the PC's codec comes into use.

[donpedro]

I don't think it matters which codec is used for original capture of DV footage

There is no codec involved during capture from camcorder.

, it's when you render edited material that the PC's codec comes into use.

You are correct. Only when some part of video is modified in any way (not simple clean cut), your PC's codec is used.

[fingernailX]

Couldn't pass a chance to complicate it more. If I 'capture' or transfer to an avi wrapper file, a dv clip from a camcorder to my hard disk and open in VirtualDub I can be decoding it with the canopus codec, the panasonic codec or the mainconcept codec depending on whats installed as a vfw codec on my machine. If I open the same clip in Vegas video I'm using their direct show filter under wdm. If I open the clip in Movie Maker or WMP I'm using the M$ built in filter. If I open it in tmpgenc, mainconcept or cce do I open with vfw or directshow? What are my priority settings in tmpgenc? What are my import module settings in MainConcept? What if I frameserve to cce using avifilesource or directshowsource?

My point is there are many different ways to 'get at' the same freaking clip and why people have some difficulty in getting a good dvdr from dv clips until they figure their best way for their best outcome.

[bugster]

One difference is, the captured AVI in MS Movie Maker and Ulead (along with others I'm sure) are AVI type-1 @ 3.45 mbts. The captured AVI from Premiere is AVI type-2 @ 3.62 mbts.

Type 2 uses seperate video and audio streams. Type 1 combines them. Type 2 is slightly less compressed than type1.

If you import type 1 AVI into premiere, it will report it as 360x240 instead of 720x480. If you convert type 1 to type 2, then import to Premeire, it will report 720x480.

For the record I do all captures in Premiere. I then edit in either Premeire or ulead depending on what I want to do.

This still makes no difference to the video and audio data actually copied from the DV cam, or the compression applied to this. In fact I beleiev the file size difference is simply due to the fact that, as stated, type 2 AVI uses seperate streams for the audio and video. This means extra header and interleaving information is required in the avi wrapper file, thus increasing the overall file size. Tha actual video and audio data packets are NOT changed in any way.

[psychoace]

http://forum.doom9.org/showthread.php?s=adc2708cc691bc2df02e78a74330d067&threadid=33526


Sorry i bet this really confused you but read its a description of all the dv codec's.


Also for people that don't want to go through a big app to capture their video here is windv http://windv.mourek.cz/ it is great and actually seperates avi's by timecode so you might have seperate things on one tape and this easily splits them for faster editing.

[donpedro]

OK, I went through that post. It still seems to prove that it doesn't metter which application you use, data are same. What it is talking about is decoders. So when file (video data) are copied from tape to PC, which decoder is used to decode data and display on monitor. It will make you think that video looks better or not, but it is still same video (data) only method od interpreting it on monitor is different. Right ?

[nerdboy69]

Correct. I have not hunted for links to back it up, but DV capture to type 1 or 2 is a copying process, not a rendering process. This is what I read before I decided upon buying a DV cam and firewire, because I was curious about what fireware card to buy and what software i should use to transfer etc. It turns out it does not matter provided the firewire card follows the IEEE 1394 protocol.

What does matter is what you then do with it afterwards. ie. How you get it from the type 1/2 format to MPEG2/MPEG1/DivX/etc.

Where the confusion often lies is where the software offers the ability to capture to another format such as MPEG2. As an example, Ulead DVD WorkShop allows you to change the capture plug-in (via Tools icon pulldown -> Change capture plug-in) to Ulead DSW MPEG capture plug-in. From there, you can change the capture settings on the Capture screen to select MPEG2/1 as the video format.

What it then does during capture is buffer the DV to a AVI and then convert that to a MPEG2/1 all in the one process. So it is doing a 2 stage process behind the scenes. Just take a look at the Capture sub-folder under the projects home folder while it is capturing to see the intermediate buffer file it is creating which receives the actual DV copy in the first place. It deletes that (somewhat large) file once the capture is finished.

So this statement in the first reply ...

For example if you capture something in a pinncale or ulead program, then go and capture that same clip in Vegas video, the one in Vegas video will look a lot better since it is a professional editing software and uses it's own codecs.

is fundamentally wrong. Freeware or any of the cheapies will do just as good a job at the actual capture. The next stage of converting and editing may, however, benefit from other software - and that as you will see is extremely opinionated and often biased by human nature (ie. people wanting to justify their own investment).

[donpedro]

The next stage of converting and editing may, however, benefit from other software - and that as you will see is extremely opinionated and often biased by human nature (ie. people wanting to justify their own investment).

Well said....

[yg1968]

Donpedro,

DV isn't lossless. The DV camcorder uses a hardware codec to record the footage to DV. The compression ratio for this DV hardware codec is the same as the software codec: 5:1. But you are right to say that the transfer of the video to the computer does not entail any further loss.

[donpedro]

yg1968, You are correct. Ones a video is on the tape in your camcorder, you should not loose anything by copying it to PC.