what the heck is "overcrank"? at DVinfo.net

Akbar Ukani · March 25th, 2009, 12:49 PM

I have had numerous users post use the word "overcrank" when it comes to sony's phu60k or the SHDC memory card option....Can someone please define to me what in the world is "overcrank"....Thanks

Craig Seeman · March 25th, 2009, 12:58 PM

overcrank - my posts when someone says they're not using ClipBrowser with CRC on.

It's a film term dating back to when cameras were hand cranked. The cranking the camera faster (or slower) would change the film playback in the projector which was at 16fps (or 24fps depending on the time period referred to).

Set EX to 720p24 p25 p30 and use S&Q and set to a faster frame rate which results in slower playback.

Of course one can learn this and many other things when using Google.
Slow motion - Wikipedia, the free encyclopedia

Brian Barkley · March 26th, 2009, 06:33 AM

Craig you must be an "oldie" like me.

Andrew Stone · March 26th, 2009, 07:28 AM

Simply put, the intent of overcrank is to get the slow motion look. It is effectively done by increasing the frame rate.

A typical scenario would be to double the frame rate. So if you are in North America shooting at 29.97 (30) frames a second you would set your EX camera to 60 frames using S&Q mode at 720/60. The big caveat that some people don't know or forget is that to get effective frame rate increases on the EX you have to be shooting in 720 and not 1080.

You can "apparently" shoot up to 42 frames of overcrank on the SDHC cards but most (read almost all) people use genuine SxS cards for "slomo" work. It's not worth the risk of dropping frames. The Sony hardisk recorder has the same bandwidth limitations as the SDHC cards so I would avoid using that as well for slomo shooting.

Mike Chandler · March 26th, 2009, 03:11 PM

Quote:

Originally Posted by Craig Seeman

overcrank - my posts when someone says they're not using ClipBrowser with CRC on.

Ok, Craig, now that I've stopped chuckling (sorry to hijack your thread, Akbar), I've been asking this over on another thread, but as long as you brought it up, why is it imperative to use CB when copying the entire BPAV folder. The Sony CB manual states only that, "To archive media from an SxS card to hard disc or other media, the Sony XDCAM EX ClipBrowser application must be used. Copying individual clips via the Macintosh Finder will result in unusable media on the target drive."

It doesn't say anything about not using the Mac Finder to copy the whole folder.

Is there a technical rationale against using the Finder to copy the whole folder?

Mitchell Lewis · March 26th, 2009, 03:21 PM

OMG!! You just woke up a ticking time bomb. (wait to Craig reads this!) hehehehe

Craig Seeman · March 26th, 2009, 05:59 PM

Quote:

Is there a technical rationale against using the Finder to copy the whole folder?

Is there a technical rationale for wearing seat belts? (in a world where people use smilies I should create snarlies).

ClipBrowser uses CRC which verifies the copy. ShotPut does this too.
The rationale is that you don't want to have to pay for the re-shoot or lose the client due to a corrupted master file.

As I heard yet another Sony rep say, entirely unprovoked by anyone even asking the question. "NEVER drag and drop folders or files. Use ClipBrowser!"
I have a hunch he was sick and tired of the support phone calls asking how to rescue a corrupted master clip.

Mike Chandler · March 26th, 2009, 07:06 PM

Quote:

Originally Posted by Craig Seeman

As I heard yet another Sony rep say, entirely unprovoked by anyone even asking the question. "NEVER drag and drop folders or files. Use ClipBrowser!"
.

Well, it's not a technical rationale, but it does get one's attention.

Craig Seeman · March 26th, 2009, 07:11 PM

The technical rationale is CRC. ClipBrowser and ShotPut do file verification.

Generally if you want to decrease the risk of technical problems you use ClipBrowser.
A corrupt file is a technical problem.

http://en.wikipedia.org/wiki/Cyclic_redundancy_check

Quote:

Originally Posted by Mike Chandler

Well, it's not a technical rationale, but it does get one's attention.

Michael B. McGee · March 29th, 2009, 10:48 AM

Quote:

Originally Posted by Akbar Ukani

I have had numerous users post use the word "overcrank" when it comes to sony's phu60k or the SHDC memory card option....Can someone please define to me what in the world is "overcrank"....Thanks

what is Google?

Sverker Hahn · March 29th, 2009, 04:46 PM

Why does overcrank 60 fps use up to 80 Mbs when 720/60p use 35 Mbps?

Does overcrank give a better image, frame by frame, or what?

Craig Seeman · March 30th, 2009, 12:09 AM

It's probably about 87.5Mbps at 24/60fps.

Playback will then be approximately 35mbps at the flagged playback rate.

Quote:

Originally Posted by Sverker Hahn

Why does overcrank 60 fps use up to 80 Mbs when 720/60p use 35 Mbps?

Does overcrank give a better image, frame by frame, or what?

David Heath · March 30th, 2009, 05:29 PM

Quote:

Originally Posted by Sverker Hahn

Why does overcrank 60 fps use up to 80 Mbs when 720/60p use 35 Mbps?

Does overcrank give a better image, frame by frame, or what?

Firstly, ignoring overcrank, it's important to realise that normal 720p/50 doesn't require twice the datarate of 720p/25 for the same quality per frame - key to realise is that the extra 25 frames are very similar to the original 25 per second. Hence if differences are coded, the extra information to yield the extra 25 frames is far less than required to code the first 25.

A good analogy would be building a house - if it costs £x to build a house, it will cost far less than 2x£x in building costs to build another of twice floor area.

Overcrank is different - the end playback is 25fps, which should be at 35Mbs. Record 50frames in a second, and you have to record at 70Mbs to give the correct data rates for playback.

March 25th, 2009, 12:49 PM	#1
Akbar Ukani Regular Crew Join Date: Aug 2007 Location: Lawrenceville, GA Posts: 69	what the heck is "overcrank"? I have had numerous users post use the word "overcrank" when it comes to sony's phu60k or the SHDC memory card option....Can someone please define to me what in the world is "overcrank"....Thanks

March 25th, 2009, 12:58 PM	#2
Craig Seeman Inner Circle Join Date: Feb 2004 Location: Brooklyn, NY, USA Posts: 3,841	overcrank - my posts when someone says they're not using ClipBrowser with CRC on. It's a film term dating back to when cameras were hand cranked. The cranking the camera faster (or slower) would change the film playback in the projector which was at 16fps (or 24fps depending on the time period referred to). Set EX to 720p24 p25 p30 and use S&Q and set to a faster frame rate which results in slower playback. Of course one can learn this and many other things when using Google. Slow motion - Wikipedia, the free encyclopedia Last edited by Craig Seeman; March 26th, 2009 at 08:12 AM.

March 26th, 2009, 03:21 PM	#6
Mitchell Lewis Trustee Join Date: Dec 2008 Location: Kennewick, WA Posts: 1,124	OMG!! You just woke up a ticking time bomb. (wait to Craig reads this!) hehehehe __________________ Sony EX3, Canon 5D MkII, Chrosziel Matte Box, Sachtler tripod, Steadicam Flyer, Mac Pro, Apple/Adobe software - 20 years as a local videographer/editor

March 26th, 2009, 06:33 AM	#3
Brian Barkley Major Player Join Date: Jan 2009 Location: Overland Park, KS Posts: 233	Craig you must be an "oldie" like me.

March 26th, 2009, 07:28 AM	#4
Andrew Stone Major Player Join Date: Sep 2008 Location: Vancouver, Canada Posts: 975	Simply put, the intent of overcrank is to get the slow motion look. It is effectively done by increasing the frame rate. A typical scenario would be to double the frame rate. So if you are in North America shooting at 29.97 (30) frames a second you would set your EX camera to 60 frames using S&Q mode at 720/60. The big caveat that some people don't know or forget is that to get effective frame rate increases on the EX you have to be shooting in 720 and not 1080. You can "apparently" shoot up to 42 frames of overcrank on the SDHC cards but most (read almost all) people use genuine SxS cards for "slomo" work. It's not worth the risk of dropping frames. The Sony hardisk recorder has the same bandwidth limitations as the SDHC cards so I would avoid using that as well for slomo shooting.

March 29th, 2009, 04:46 PM	#11
Sverker Hahn Regular Crew Join Date: Jun 2008 Location: Stockholm, Sweden Posts: 157	Why does overcrank 60 fps use up to 80 Mbs when 720/60p use 35 Mbps? Does overcrank give a better image, frame by frame, or what?