DV capture questions...Please reply...

VS wrote on 12/19/2003, 10:59 AM
Hi,

For Windows XP firewire capture from a NTSC DV camcorder, do I need to change my PC video resolution (e.g) from 1024x768 to whatever maximum my monitor supports? This question also holds good for editing/rendering and all the way up to DVD authoring.

Also, when does a DV codec gets involved in the whole process?
I heard that there is no codec involved during firewire capture. If this is true, when does a DV codec get involved? For example, if I render straight out to MPEG-2 for DVD from within Vegas timeline, I guess the MPEG-2 codec will get involved here. If thats the case, when is DV codec involved?

Would appreciate replies.

- VS

Comments

Jay Gladwell wrote on 12/19/2003, 11:42 AM
VS, I'm not aware of any reason to change your PC monitor resolution for capturing or editing or rendering or burning to DVD. The monitor's resolution has no effect on the video whatsoever.

My understanding is that the codec is introduced once the video is imported to the application in question, such as Vegas, and then rendered. Vegas has a wonderful reputation for having one of the best DV codecs in the industry.

There are others here far more qualified than I to explain all about codecs.

J--
JohnnyRoy wrote on 12/19/2003, 12:41 PM
The term “firewire capture” is actually a misnomer (although we all use it). It’s not a capture at all. It’s a file copy from tape to disk. So the DV codec gets involved when your camera records the image on tape. What you are doing with the firewire card is transferring the already encoded DV information from the tape to your hard drive unaltered. That means absolutely no loss in quality.

When you drop the file on Vegas, it uses its DV decoder (not encoder) to interpret the file and display it. If you change the file to add an effect or title overlay, Vegas will use its DV encoder to re-encode only the part you changed with whatever changes you made. Note this does not happen for simple cuts. This is only for when you alter the video image in some way. If you then render to an AVI file or print back to tape, Vegas will copy all the unchanged video along with the changed video it re-encodes to the file or tape. So any unchanged video will return to your camera or a new file will no loss in quality. (BTW you will not see a difference in quality anyway since the Vegas DV encoder is exceptional)

If you make a DVD, Vegas (or DVDA) uses its MPEG2 encoder to re-encode the video to MPEG2 format.

~jr
kameronj wrote on 12/19/2003, 12:45 PM
Blah blah blah....JohnnyRoy.....all those words! What.....I bet you went ta school to get lernt on all those fancy two dollar works like misnomer.

I knew a misnomer. She was my kindegarden teacher. That is until I dropped out!! I wonder what ever happened to her!!!















(I'm jus funnin with ya - if ya hadn't figured that one out already!) :->
(that's me....I'm a funner!!)
JohnnyRoy wrote on 12/19/2003, 2:38 PM
Actually I only paid $1.25 for those words. You must have left school before misconception taught economic. Misconception was my favorite. ;-)

~jr
VS wrote on 12/19/2003, 4:24 PM
Hi JohnyRoy,

YOU ARE THE MAN.

I got it.

My only question here is:

When I add a transition/filter/overlay, as you said, DV codec will encode the parts of the video that has these filters and the rest of the video is untouched.
Now, for example, I added a filter/transition on top of my captured DV file and export it as MPEG-2 for DVD. What happens here? Is both DV codec and MPEG-2 codec get involved here since I added a filter/transition and also doing a export to MPEG-2?

Would appreciate your expert reply as before.

- VS
Chienworks wrote on 12/19/2003, 8:05 PM
In that case, the SONY DV codec is used to uncompress the frame, then the effects/editing/whatever is applied to the uncompressed version, then the MPEG codec (presumably Main concept) is used to compress the frame to the final output format.
JohnnyRoy wrote on 12/19/2003, 8:33 PM
As Kelly said, if you change your video and render to MPEG2 it will not be re-encoded as DV and then to MPEG2. It will just be encoded to MPEG2. The only time the changed video will be encoded to DV is if you print back to DV tape or if you render as a DV AVI file.

~jr
busterkeaton wrote on 12/19/2003, 8:49 PM
One way to think about it is any time you change something outside the framelines--putting scene ten next to scene one, cutting out the first 120 frames of scenes of scene four-- does not get reencoded. Anytime you change things within the frameline--add titles, change the colors, dissolve two video tracks, change the amount of data within the frame (i.e. go from DV to mpeg), etc you will need to reencode. If you mix the type of media on the timeline, DV, mpeg, jpeg, gif you will have to encode to get into a single format when you are done.

The first situation is about time, the second situation is about content/data.