Film Speed/Video Speed Workflow Confusion!

[subwoof]

I have a friend who does ADR for various studios. He is frustrated because there seems to be no "standard" in post-production Pro Tools editorial for sample rate, bit depth, pull-down, film speed, video speed, video codecs, etc. He is confused (as I am to a point!) as to how to wrap his head around all of this. Is there a reference someone could recommend that explains in layman's terms how pull ups and pull downs at 48khz work to change speed as compared to a recording in a session at 48khz with Pro Tools set to do a pull down -.1%, and how 29.97 vs 30 fps figure into all of this? He understands the basic film speed versus video speed, but how 48,048 and 47,942 relate to speed and video frame rates of 30fps and 29.97 fps and physical Pro Tools pull-downs is soooo confusing, not to mention getting a Quick Time at one speed (24 or 30) and an OMF at another speed and why this happens!

Any articles or past postings or books on the subject would be appreciated. (Simple ones, not White Papers!!)

Thanks

Mike

[dr sound]

Mike,
Look here:
http://www.gearslutz.com/board/post-...st-corner.html

Go to the Feb 6th posting half way down the page.

[subwoof]

Thanks Marti!

Mike

[CD Productions]

I would also highly recommend John Purcell's book "Dialogue editing for motion pictures". Great explanations of time code and workflow.

[Brent_Sydney]

There is also a good explanation of pull ups/downs in the PT 7.4 reference guide.

Pages 888-893 or so under SMPTE pull up and downs. Its only part of the picture, but one which is often misunderstood, confusing the whole picture...if you know what I mean.

[Starcrash]

Originally Posted by Brent_Sydney

There is also a good explanation of pull ups/downs in the PT 7.4 reference guide.

Pages 888-893 or so under SMPTE pull up and downs. Its only part of the picture, but one which is often misunderstood, confusing the whole picture...if you know what I mean.

Really? I've always thought that they really glossed over the details in the Reference Guide. It's barely a page and a half and doesn't answer the OP's question, "how [do] pull ups and pull downs at 48khz work to change speed as compared to a recording in a session at 48khz with Pro Tools set to do a pull down?". Assuming no SYNC peripheral, what is "physically" happening when you record, say Foley, in a 48k session with .1% down engaged? Is it still recording at 48k or 47.952?

What about when you are using a SYNC I/O?

What about PTHD vs. DVTK LE in relation to pull ups/downs? Is there a difference in the way it's handled. Are the sessions interchangeable between HD and LE?

Another key factor that isn't explained properly in the manual is under what circumstances does importing session data from a pulldown session into a non-pull session cause material to be out of sync? I've worked on shows where half of the crew was pulled down and the other not and there were definitely some unexplained phenomena going on.

I think they could go a long way to improve that section of the manual.

[subwoof]

Good points Pascal. I have the exact same questions...

Mike

[rcutz]

hi guys...

please take a look on this doc, from digidesign... it`s nice

it`s linked from my site, because i don`t remember where it goes on digi`s site...

film sync chart

I hope it helps

ricardo
www.ricardocutz.com.br

[Starcrash]

Originally Posted by rcutz

hi guys...

please take a look on this doc, from digidesign... it`s nice

it`s linked from my site, because i don`t remember where it goes on digi`s site...

film sync chart

I hope it helps

ricardo
www.ricardocutz.com.br

That's a handy doc. Thanks rcutz. I don't think it answers Mike's question, though.

Let me take a stab since no one else has chimed in yet. This is how I understand what is happening. Please correct me if (when) I'm wrong.

No SYNC I/O or other sync peripheral device:
With .1% pulldown engaged in a 48kHz session, all audio still plays and records at 48kHz and only the timeline increments reflect the pulldown to video speed.

Using SYNC I/O:
With .1% pulldown engaged, all audio will play and record at 47.952kHz because it is clocked to the SYNC device.

As far as the placement of regions and sync, this is where it gets a bit dodgey. I believe PT place regions on the timeline according to sample position rather than TC stamp which means that changing to pulldown will not "move" the sync of the region, but rather the TC ruler itself. That said, clocking to a SYNC or other device at 47.952 will cause the regions to be played as if they were placed differently because the reference is slightly slower (video speed).

However, and this is where I could be wrong, Import Session Data seems to be interested in timestamp. Importing tracks from a non-pull session into a pull session has caused problems for me in the past.

"Experts", chime in!

[rcutz]

Originally Posted by Starcrash

No SYNC I/O or other sync peripheral device:
With .1% pulldown engaged in a 48kHz session, all audio still plays and records at 48kHz and only the timeline increments reflect the pulldown to video speed.

Using SYNC I/O:
With .1% pulldown engaged, all audio will play and record at 47.952kHz because it is clocked to the SYNC device.

As far as the placement of regions and sync, this is where it gets a bit dodgey. I believe PT place regions on the timeline according to sample position rather than TC stamp which means that changing to pulldown will not "move" the sync of the region, but rather the TC ruler itself. That said, clocking to a SYNC or other device at 47.952 will cause the regions to be played as if they were placed differently because the reference is slightly slower (video speed).

Hi...
The pulldown ou pull up will change the speed of the playback, it`s the same of playing a long play of 33rpm with 45rpm.

The timecode is a adress.. where you audio must be spoted...

If you have a bunch of audios recorded at 48khz with a tc adress of 24fps (wich is the most common situation on production recordings) and play it against a image with 29.97 fps time code, it will almost be in the correct place, but it will start to get out of sync, with the ratio of 1.8 seconds per minute, I guess, because the speed of the image is different.

The are no difference to use pulldown on a protools session on LE ( no SYNC HW) or in a protools HD with SYNC I/O or the legacy USD.

I can do it in any protools version, LE, MIXPlus of HD. With ot without a external clock reference.

The question is to be sure to what reference you are locked- VIDEO SPEED (29.97 fps) or FILM SPEED (24fps)- forget about the europeans... joke...

The first question is: wich settings the image guys are using?
Your audio has been recorded at film speed or video speed?
The audio has been pulldownled on the telecine process?

And as you said the pullup/ down don`t change the time code rule... and the spot is made based on the timecode (stamped or not) not by the audio speed.

Once in the right place -"timecode adress"- the audio will still in sync or not if it was in the same speed of the image, agree?

am I still in the topic? :)

I hope it helps...

and sorry my english lacks...