Duplicating a MiniDV? at DVinfo.net

Roland Gatto · April 29th, 2007, 09:31 PM

Hello! I was wondering how to duplicate a minidv. Is there a way to transfer it to my computer then transfer it to a blank minidv via the hv20?

Thanks!

Ervin Farkas · April 30th, 2007, 06:22 AM

The easyest way would be to play the tape on one camcorder and record it with another one connected via firewire, but if you don't have another camcorder, than yes, capturing and exporting back to tape will give you an exact replica.

Steven Gotz · April 30th, 2007, 07:34 AM

That only applies to DV AVI. It does not apply to HDV. For HDV the only way to get an exact copy is tape-to-tape.

John Miller · April 30th, 2007, 08:30 AM

Note that with DV, typically the timecode will get rewritten unless you have a suitably "pro" camcorder that will preserve the incoming timecode. All the other stuff (time, date, camera settings etc) typically are preserved.

R Geoff Baker · May 2nd, 2007, 09:08 AM

"That only applies to DV AVI. It does not apply to HDV. For HDV the only way to get an exact copy is tape-to-tape." (Gotz)

Why is that?

GB

Steven Gotz · May 2nd, 2007, 09:14 AM

Keeping in mind that we are in the Premiere forum, and I did not take into account any software that might be smart enough to send clips back to tape without re-encoding, Premiere Pro is not smart enough to do the job.

Why? I don't know. It shouldn't be as hard as they make it out to be.

If you capture DV, put it on a timeline, then put it back to tape, you can do this over and over and over with no loss. It is basically a file transfer.

If you put HDV on a timeline, it gets re-encoded as it is laid back to tape. Just seeing how long the delay is before it starts to write to tape is an indication that something bad is happening.

I wish I knew "why" but I don't.

R Geoff Baker · May 2nd, 2007, 05:01 PM

Thanks for the explanation. I take from this there is no ability to stop recompression for an HDV export from Premiere.

GB

Steven Gotz · May 2nd, 2007, 06:52 PM

That's my understanding. You would think that the MainConcept plugin would allow it, but I haven't tried it and I haven't heard that many people rave about it. It would be pretty easy to test. If the export started immediately then no re-encoding could be involved. If it took even a little while, then that answers the question.

Matt Vanecek · May 6th, 2007, 01:31 AM

Is the DV export back to tape re-encoded as DV, or is it just a straight transfer? I.e., is PPro writing back the original bits, or does it re-encode (with the resultant 5:1 encoding ratio) the already-5:1-DV file?

Thanks,
Matt

Graham Hickling · May 6th, 2007, 08:48 AM

Premiere does 'smart rendering' for DV, so that only material that has been edited (beyond simple trims) gets recompressed. There's also a 'recompress' checkbox in the Export dialog, if you WANT to recompress the whole thing.

(The recompressed file will be the same size of course - it doesnt get another 5-fold shrink...)

Matt Vanecek · May 6th, 2007, 09:18 AM

Wouldn't it be better to export your edits to a lossless format, and then export the lossless file to tape? Or does it not make a difference?

Thanks,
Matt

Harm Millaard · May 6th, 2007, 10:01 AM

Quote:

Originally Posted by Matt Vanecek

Wouldn't it be better to export your edits to a lossless format, and then export the lossless file to tape? Or does it not make a difference?

Thanks,
Matt

How do you think the camera can handle that? It is a DV (5:1 compressed) flow that it is designed to record, nothing else.

Matt Vanecek · May 6th, 2007, 11:38 AM

Quote:

Originally Posted by Harm Millaard

How do you think the camera can handle that? It is a DV (5:1 compressed) flow that it is designed to record, nothing else.

I wasn't clear. Of course you'd compress to DV to go to the camera, but before then--to render all your effects, etc., w/o re-compression, wouldn't it be better to go to a losless codec and then take the final product to DV to tape?

I'm still trying to figure out when things get recompressed and when they don't. Steve G. said that PPro is smart enough to only recompress changed material. But if you apply an effect to the entire movie (e.g., color balance or unsharp mask), then PPro has to re-encode the entire thing, right? For DV, how does that re-encoding the original 5:1 DV to a new 5:1 DV not result in generational loss? On the flip side, because you may want to take the movie back out to DV tape, is there really any gain in going lossless, because you have to re-encode 5:1 anyhow, so you're still encoding original 5:1 footage by an additional 5:1 factor....

I hate math...

I'd really like to know, though, the answers to the above. I get lost in the myriad of codecs sometimes, and in what degrades quality vs. maintains quality, etc. I can see exporting to a lossless codec (some quicktime, blackmagic 10, huffyuv, or just uncompressed) for ingest into a compositing program. I'm still struggling with the back-to-tape issue myself, though, without generational loss due to recompression. What am I missing?

Thanks,
Matt

Harm Millaard · May 7th, 2007, 05:02 AM

Matt,

You will gain nothing from using lossless codecs when you still have to convert to DV. It will only cost time and storage. One generation loss for all the rendered parts of your time line can not be avoided, the rest is unaltered as Steven said earlier. The only advise I can give is to finish your editing and then export to tape. Avoid repeating this step if you want to make changes to your project, do that before exporting.

Matt Vanecek · May 7th, 2007, 07:28 PM

Harm,
Thanks for the confirmation. That's very disappointing but emphasizes what I've been researching...

I still need to output to lossless, though, as I do composite and color correct in AE. It may just be me, but I find the Color Finesse engine in AE to produce better output, and it produces even better output when working on lossless input. I verified that (at least visually) on my HD TV--the original looked crappy so I went back and made sure everything was lossless to final render. Yup, took a lot of space, but the final output is worth it.

I'm really looking forward to that HDMI field unit Stephen Armour is working on--that ought to help with the whole compress-recompress issue, without being tethered to a studio computer. Maybe I'm just getting too snobby since I got an HD TV...

Thanks,
Matt

April 29th, 2007, 09:31 PM	#1
Roland Gatto Regular Crew Join Date: Mar 2007 Location: Dallas Posts: 41	Duplicating a MiniDV? Hello! I was wondering how to duplicate a minidv. Is there a way to transfer it to my computer then transfer it to a blank minidv via the hv20? Thanks!

April 30th, 2007, 06:22 AM	#2
Ervin Farkas Inner Circle Join Date: Aug 2005 Location: Atlanta/USA Posts: 2,515	The easyest way would be to play the tape on one camcorder and record it with another one connected via firewire, but if you don't have another camcorder, than yes, capturing and exporting back to tape will give you an exact replica. __________________ Ervin Farkas www.AtlantaLegalVideo.com

April 30th, 2007, 07:34 AM	#3
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	That only applies to DV AVI. It does not apply to HDV. For HDV the only way to get an exact copy is tape-to-tape. __________________ Steven Gotz http://www.stevengotz.com

May 2nd, 2007, 09:14 AM	#6
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	Keeping in mind that we are in the Premiere forum, and I did not take into account any software that might be smart enough to send clips back to tape without re-encoding, Premiere Pro is not smart enough to do the job. Why? I don't know. It shouldn't be as hard as they make it out to be. If you capture DV, put it on a timeline, then put it back to tape, you can do this over and over and over with no loss. It is basically a file transfer. If you put HDV on a timeline, it gets re-encoded as it is laid back to tape. Just seeing how long the delay is before it starts to write to tape is an indication that something bad is happening. I wish I knew "why" but I don't. __________________ Steven Gotz http://www.stevengotz.com

May 2nd, 2007, 06:52 PM	#8
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	That's my understanding. You would think that the MainConcept plugin would allow it, but I haven't tried it and I haven't heard that many people rave about it. It would be pretty easy to test. If the export started immediately then no re-encoding could be involved. If it took even a little while, then that answers the question. __________________ Steven Gotz http://www.stevengotz.com

April 30th, 2007, 08:30 AM	#4
John Miller Major Player Join Date: Oct 2005 Location: Hillsborough, NC, USA Posts: 968	Note that with DV, typically the timecode will get rewritten unless you have a suitably "pro" camcorder that will preserve the incoming timecode. All the other stuff (time, date, camera settings etc) typically are preserved.

May 2nd, 2007, 09:08 AM	#5
R Geoff Baker Major Player Join Date: Jan 2005 Location: Ottawa, ON Posts: 471	"That only applies to DV AVI. It does not apply to HDV. For HDV the only way to get an exact copy is tape-to-tape." (Gotz) Why is that? GB

May 2nd, 2007, 05:01 PM	#7
R Geoff Baker Major Player Join Date: Jan 2005 Location: Ottawa, ON Posts: 471	Thanks for the explanation. I take from this there is no ability to stop recompression for an HDV export from Premiere. GB

May 6th, 2007, 01:31 AM	#9
Matt Vanecek Major Player Join Date: Jul 2005 Location: Denton, TX Posts: 334	Is the DV export back to tape re-encoded as DV, or is it just a straight transfer? I.e., is PPro writing back the original bits, or does it re-encode (with the resultant 5:1 encoding ratio) the already-5:1-DV file? Thanks, Matt

May 6th, 2007, 08:48 AM	#10
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Premiere does 'smart rendering' for DV, so that only material that has been edited (beyond simple trims) gets recompressed. There's also a 'recompress' checkbox in the Export dialog, if you WANT to recompress the whole thing. (The recompressed file will be the same size of course - it doesnt get another 5-fold shrink...)

May 6th, 2007, 09:18 AM	#11
Matt Vanecek Major Player Join Date: Jul 2005 Location: Denton, TX Posts: 334	Wouldn't it be better to export your edits to a lossless format, and then export the lossless file to tape? Or does it not make a difference? Thanks, Matt

May 7th, 2007, 05:02 AM	#14
Harm Millaard Trustee Join Date: Aug 2006 Location: Rotterdam, Netherlands Posts: 1,832	Matt, You will gain nothing from using lossless codecs when you still have to convert to DV. It will only cost time and storage. One generation loss for all the rendered parts of your time line can not be avoided, the rest is unaltered as Steven said earlier. The only advise I can give is to finish your editing and then export to tape. Avoid repeating this step if you want to make changes to your project, do that before exporting.

May 7th, 2007, 07:28 PM	#15
Matt Vanecek Major Player Join Date: Jul 2005 Location: Denton, TX Posts: 334	Harm, Thanks for the confirmation. That's very disappointing but emphasizes what I've been researching... I still need to output to lossless, though, as I do composite and color correct in AE. It may just be me, but I find the Color Finesse engine in AE to produce better output, and it produces even better output when working on lossless input. I verified that (at least visually) on my HD TV--the original looked crappy so I went back and made sure everything was lossless to final render. Yup, took a lot of space, but the final output is worth it. I'm really looking forward to that HDMI field unit Stephen Armour is working on--that ought to help with the whole compress-recompress issue, without being tethered to a studio computer. Maybe I'm just getting too snobby since I got an HD TV... Thanks, Matt