Skip to main content
B
Brizdale
Participant
May 16, 2020
Question

iPad Pro screen capture frame rate issue - my video is getting truncated when I bring it into AE

  • May 16, 2020
  • 1 reply
  • 1243 views

So I've been doing some screen captures of myself working on my iPad Pro to post to YouTube but after a recent update it reset the capture function to the default setting of having the microphone in the off position, so I rewatched my own video and recorded a voiceover, thinking I'd simply bring the file into after effects and throw the audio on there and render a new version to throw up on youtube. Easy, right? 

Well when I bring the 52 minute video (mp4) into AE (CS5), it informs me that the frame rate is 51.7126 FPS and I get the typical 17 18 incompatibility warning that I've encountered many times in the past and have fixed simply by changing the frame rate to a whole number. The problem is that once I do this, no matter what number I change it to (I started with 52 but have tried many different numbers since), it cuts my video off at about the 22 minute mark. I'm losing a half hour of my video and I can't figure out why. I have toyed with the footage frame rate and I've toyed with the composition frame rate; neither make any difference. They change the playback speed of the video, obviously, but nothing I know to try recovers the full length of the video.

 

The video plays fine in preview, QuickTime, or any other app - all 52 minutes. It's only when I bring it into AE that it's getting cropped. Can anyone more knowledgeable than I please tell how to overcome this problem? I have a feeling it's not overly difficult, but I haven't been able to find anything via internet searches or searches here on the forum. Thanks in advance for your time and assistance!

 

I'm using a

mid 2010 Mac Pro running OS X 10.11.6

2 x 2.4 GHz quad-core Intel Xeon

56 GB ram 1066 MHz DDR3 EEC

ATI Radeon HD 5770 1024 Mb

This topic has been closed for replies.

1 reply

R
Community Expert
Rick GerardCommunity Expert
Community Expert
May 17, 2020

When you lock a variable frame rate movie to a constant frame rate and there is no audio track you might be dropping a bunch of frames. If nothing is changing in the frame for 5 or 6 frames you might have a single frame that is 5 or 6 frames long. Locking the frame rate That could account for the hour-long video running out of frames before the video is over. I don't know for sure if that is what is going on, but it is not an unreasonable explanation. It has been a long time since I worked with a development team designing compression algorithms but we did a lot of really weird stuff to video frames in the early days. 

 

I see a couple of workflow issues. The first, and most obvious one, is that it sounds like you are trying to edit a movie that is almost an hour-long in After Effects.

 

The second probable issue is that it sounds like you are worried about matching the comp frame rate and even possibly frame size with the source video. Screen Captures are almost always variable frame rate. After Effects does not work that way. AE carefully recreates every single pixel in a color compressed and interframe predicted frame from the MP4 video to a completely uncompressed 8 to 32 bit per color channel pixel and then builds every frame as a group of those pixels. No averaging or predicting is allowed. 

 

I didn't record an hour but I recorded a couple of minutes with my iPhone, the frame rate came in at 55.996 so I just left it at that. I then placed the video in a standard HD 29.97 fps comp and just sized it to fit. Since there are more frames in the original footage than in the comp, and the human eye can't really distinguish anything between about 16 and 30 fps unless you are carefully trying to analyze motion, nobody will ever know that I'm not showing all of the captured frames. I get no warning of any kind about the video. 

 

If you intend to edit the video, add titles, pause sections, and maybe do a little detailed description in some parts of the video for a YouTube demo I suggest that you start off by dropping the video in a Premiere Pro sequence that has a standard frame rate and frame size, then do your editing there. It will take you about 1/10 the time that it would to edit in After Effects and the final video will render in a lot less time. The sections (cuts or short sequences) that need some fancy effects that cannot be done in Premiere Pro can be processed by rendering the cut to a suitable production format or using Dynamic Link and the frame rate of the sequence will be maintained. Premiere Pro or After Effects, through the Adobe Media Encoder, are going to do a lot better job of rendering your video to the standard frame rate and frame size that YouTube recommends than YouTube is going to do with your video if you send them a funky frame rate. You'll get a better product using standard frame rate comps and 29.97 is more than adequate for this kind of video. The Road Runner cartoons were actually only 12 frames per second and they looked great.

 

If you really must process the entire hour-long video in After Effects and you can't resolve the issue by just dropping the footage in a standard frame size and frame rate comp then you will have to drop the video in Premiere Pro, trim the useless parts, and render a standard frame rate production master for use in AE. You could also use the AME but you will have to make sure the frame rate is set to 29.97 or 30 or one of the other standards.

 

 

B
BrizdaleAuthor
Participant
May 17, 2020

Thanks for the input! I was only using AE because that's what I'm most familiar with. That's what I used for several years doing motion graphics. Premier Pro really is the better route to go. I'm just going to have watch some tutorials to figure it out. And yes, I would hope, and expect, the result to be a typical 29.97fps. 

I was just shocked that AE was truncating the video. I guess it really isn't made to handle video of that length, or video that hasn't been processed first. 

R
Community Expert
Rick GerardCommunity Expert
Community Expert
May 17, 2020

I put long clips in AE all the time, but I trim them to the frames that are going to be in the final edit. I never edit anything longer than three or four shots in a sequence in AE because it's just too inefficient. I only create sequences when I need a specific type of transition that I can't create in an NLE, like an actor jumping magically between three or four different locations. If I had an actor that needed to magically jump from his home to the top of a building, to a car  I might even just do the transition between home and the top of the building in one comp and the transition the jump from the top of the building to the car in another and just do a match cut between these two sequences in the NLE.

Terms & ConditionsAccessibility statement
Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices