AE CC 2019 - The source compression type is not supported

IN WINDOWS, it may be a long path issue, just move the files closer to the root folder and works like a charm

The issue occurred when opening the project in After Effects 2020. After Effects refused to import files with the MOV extension and an alpha channel with the following specifications:

Format: MPEG-4
Format profile: QuickTime
Codec ID: qt 2005.03 (qt)

I attempted to convert these files, but Media Encoder also failed to import them.

The problem was resolved with the help of Shutter Encoder. I converted the files to the Apple ProRes 4444 format, retained the alpha channel, and was able to open them in After Effects.

Re-opening this thread as there's more to this problem than just codecs. 

TL;DR version: Try shortening the directory path.

-- I exported files to Media Encoder from AE2023 (win10), created mp4s, and replaced my original .mov source in my AE project (archiving project, so I'm downsampling footage).  

-- Upon re-open, all the newly replaced files (now mp4) have the "unsupported or corrupt" error.

-- Moved half of the suspect files to the desktop and re-linked successfully. Unmoved half still have error.

-- Moved same files back to original location in the collected (Footage) folder, and error returns for all mp4s

-- Closed AE and made a duplicate of the entire Collected project folder. Re-opened copied folder with same errors

-- Moved project folder a few folders up in my hierarchy and opened -- NO ERRORS.  -- Closed and Quit AE.

-- Moved project folder back to the original location

-- Delete aforementioned "copy" of project but receive an error that "file names are too long for Recycle Bin" and "Folder is currently in use -- can't delete".  (hmmm. This is suspicious)

-- Systematically reduce the length of folder names in file path, saving approximately 50 characters.  

-- File opens with fewer mp4 errors. (10 instead of 15)

-- Truncate/abbreviate folders even further.  File opens with NO ERRORS.

This is actually a problem I had once before as well, and while it's definitely a "directory path too long" problem in my case, it's still unclear if it's specific to Windows 10, and/or Dropbox, both of which I'm working inside of. When I had the problem before, it occurred with a Dropbox 'shared' folder from a mac-based client who was not experiencing any errors. This suggests it may be a Windows-only problem. Shortening that directory path was even more difficult since it wasn't even my directory!

Hope it helps. Let me know if you discover more insights.

Hello, I am restarting this thread
If you have this issue when you are working from a collection of projects (lots and lots of files) -> Move the rushes to another folder on your computer and link a new time the elements together: there is no more compression problem.
Hope this can help someone

Hello,

My source files are FLV , however I get same error once I try to import them. I am using Adobe ME 2020.

Any clue ?

If I understand this correctly, Adobe significantly reduced the number of codecs it supported in the CC2018 release. I have thousands of VFX asset files that are now no longer supported. My options are to use a version of After Effects that Adobe has previously told me that they would sue me for using, or convert thousands of assets to a lossy format? 

Not sure if it helps anyone else but I searched several forums for a solution that would work. Finally found a link to Handbrake:

https://handbrake.fr/downloads.php

which I used to convert the file and now it works to import it to AE. 

I have the same problem here. It is highly annoying. Can't use files I used to use in my recent projects.

Hello,

Have you checked the codec you have set?

Supported file formats in After Effects CC