Drift in After Effects

roeit
roeit Website User Posts: 2 Just Starting Out
edited September 2020 in CamTrackAR

Hi, I tried capturing a video through my iphone. in my iphone everything looked solid and tracked properly, but when I viewed it in after effects there's a drift. I am using the trial version, so exported the data to blender and from there to after effects. in after effects the footage I shot is 59.976 whereas the comp from the data is 60fps... that's already a problem. also there's seem to be a drift. changing the footage frame rate won't fix it. I think this drift was not there when I captured the video. the pin was not shifting this way.

so a few questions:
1. can I choose the frame rate of the video before I record it? 
2. I want to see this actually works before I purchase it, but the blender-after effects export should work. can you please check what is causing the drift? maybe how to fix it? or any advice how to do this properly? I am quite sure that in the app it was fine. 
here are the files:
https://drive.google.com/drive/folders/1vQR64GFepVVf1IPM8k9Es2YhywSxUUBt

Comments

  • NormanPCN
    NormanPCN Website User Posts: 4,063 Enthusiast

    The media was recorded by a phone is phones normally capture variable frame rate media. Which is the case with this media file.

    Variable frame rate media can cause audio drift in Hitfilm. The solution is to transcode to constant frame rate media.

    MediaInfo reports.

     Format : MPEG-4

    Codec ID : M4V (M4V /M4A /isom/mp42)Video

    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Bit rate : 27.8 Mb/s
    Width : 1 920 pixels
    Height : 1 080 pixels
    Frame rate mode : Variable
    Frame rate : 59.940 (59940/1000) FPS
    Minimum frame rate : 30.000 FPS
    Maximum frame rate : 60.000 FPS

  • roeit
    roeit Website User Posts: 2 Just Starting Out
    edited August 2020

    Thanks Norman! great info I should have known to check this when the frame rate was weird and not standard. I tried to convert it to constant frame rate in Handbrake. now it is constant and it is better but still some drift which make it unusable. the file is in the same folder the m4v one if you wish to examine. I tried another test and took another shot - this time the footage was constant, still some drift, not usable. the footage is also in the folder I posted. 

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