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“A” Frames and what to do now
Hi all,
This is my very first post so be gentle. I am a fairly newby editor working on a documentary for a client. We took our project to a post production house and when we were sending out to tape (b4 color correction) we found a problem with “A” Frames adding ghost images. I had only heard of “A” frames as a technical fact with no mention to be mindful of them while cutting. I went to film school but we only had a crash course in editing.
Anyway,
We had to return with our heads in our hands and begin re-conforming the project.
Our project consists of Film content that was converted to 29.97 and dv footage.
My question to the fine and Knowledgeable Creative Cowians is;1. do I have to go in and re-edit every single clip to make sure it doesn’t start or end on an “a” frame? or do I just have to look for problem “A” frames and make sure they end on non interlaced footage.
2. if I just corrected the problem clips is there a potential for another clip that seemingly ends visually alright to then shift to a bad frame later in the offline.
3. what do I do with transitions over the film footage. Do they have to be an even number of frames so that the crossfades don’t end on an interlaced frame?
4. does slowing down or speeding up a clip affect this somehow and what considerations have to be made.
5. if I do have to go through and make sure every single one of these clips starts and ends on an “A” frame then is there any filters or shortcuts that you can think off to save weeks of time?
Thank you for reading this and for any advice that you can provide. I must say that a cyanide pill is not entirely out of the question because this is such a monumental fix if I am right.
You guys are the best and this site has helped me so much over the last year and a half. You guys are awesome.
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5 Replies
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Let’s back up for a second.
You laid off a tape to get color corrected? Or someone else is re-conforming the project at high res for you?
My first instinct is the post house you went to is doing something wrong or not communicating with you well about the issue.
Unless something went completely haywire with your video dailies, I really really doubt you have to “re-edit.”
The “A” frame is simply the first frame of a 5 frame sequence that turns 24fps film into 30fps video.
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Thank you for your reply. I am not that knowledgeable about these things so bear with me.
We have 10-bit uncompressed and dv footage on the timeline. When we went down to have it color corrected they noticed the ghosting on frames relating to the 10-bit which was originally shot on film. I had never heard about the necessity of cutting on A-frames so we have some interlaced final frames which I guess causes mucho problems. Now my boss wants me to go through the 1 hour and 40 minute project clip by clip making sure that the in and out edit points fall on an A frame. To make things infinitely more complicated we have a full mastered sound lock in which much of the footage is timed to beats and dialogue.The post house says we need to have the A frames dealt with before going out to color correction. There tech guys are quite knowledgeable but couldn’t definitely tell me if I had to do EVERY single clip or just the obvious ones.
As for the color correcting. We have hand conformed the 10-bit uncompressed ourselves because there were some weird timecode sync problems. As far as I can know, we are to provide them with a final 10-bit movie file and an EDL and then the divinci knows about the cuts using the EDL.
That is about it.
Thank you for your time Aaron
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1st: the whole “cuts need to be on an A frame” is completely bogus! don’t do something rash like that!
Is the 10 bit footage an already cut movie? Are you taking clips from something that’s been assembled before and putting them into your new movie? Or is it dailies from a roll of 35/16mm?
Are you cutting on a 10bit timeline or DV?
Do you have a TV monitor that you’re working with, or just looking at the computer screen while editing?
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Charles,
There’s a ton of important information you’ve left out. Don’t think anyone can help you without knowing certain things.
1. What frame rate was your source footage originally shot on?
2. What frame rate was it converted to when you captured it? The DV footage is probably 29.97. So if it was shot on film, then some form of pulldown was added. There are different types and you’ll have to identify what it is. It could be 24pA “Advanced Pulldown” which if it is then you’re very lucky because it would be very easy to convert that footage back to 23.98.
3. What format is your sequence?
4. Are you mixing different frame rates in the same sequence? Note, I’m not talking about the frame rate FCP thinks it is. I’m talking about the original frame rate the footage was shot on.
5. What format are you delivering on? Film, tape?
6. How is this going to be shown? Broadcast, DVD, web, theatrical?
7. Are you using this online facility to re-assemble your footage, or are they just color grading it?Sean
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Thank you
Aaron and Sean for your replies. Sorry for the timelapse.
here are the answers to your questions (I hope)“Is the 10 bit footage an already cut movie?”
Yes, The 10 bit was from a feature film that didn’t quite make it. It was shot in film then transferred to tapes then made into 10-bit uncommpressed files.“Are you cutting on a 10bit timeline or DV?” yes we are cutting on a 10-bit timeline.
“Do you have a TV monitor that you’re working with, or just looking at the computer screen while editing? ”
We only have a computer screen and a actual tv to view it on. We do not have access to a TV Monitor because there are no rental houses in town here.Thank you Aaron for helping with your good advice.
Now for Sean
“1. What frame rate was your source footage originally shot on?” 24for the film and 29.97 for the DV footage.
“2. What frame rate was it converted to when you captured it? The DV footage is probably 29.97. So if it was shot on film, then some form of pulldown was added. There are different types and you’ll have to identify what it is. It could be 24pA “Advanced Pulldown” which if it is then you’re very lucky because it would be very easy to convert that footage back to 23.98.”
I am not sure how to find out what kind of pulldown was added but it was done by a profesional post house. Is there a way to check?
“3. What format is your sequence? ”
10 bit uncompressed at 29.97“4. Are you mixing different frame rates in the same sequence? Note, I’m not talking about the frame rate FCP thinks it is. I’m talking about the original frame rate the footage was shot on.”
The frame rate off all the footage is 29.97
“5. What format are you delivering on? Film, tape? ”
We will be releasing it on DVDs to Film festivals as well, then we will be transferring it to film.
“6. How is this going to be shown? Broadcast, DVD, web, theatrical?”
Potentially all of them and we are planning for all of then.
“7. Are you using this online facility to re-assemble your footage, or are they just color grading it?”
We attempted to have them do the offline and it went kablooey so we got all the footage off the tapes in 10-bit and are now just finishing reassembly over the original timeline.
The post house will be doing the color correction as well as transferring it to film
When I am finished tweaking every clip, we are supposed to provide them with a 10-bit uncompressed file and an EDL and then they will use the EDL for the Davinci.
That is about all I know and I think you immensely for your advice.
Charles
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