I have seen this kind of thing in the past and have been able to solve it by purging the cache. It happens most often with codecs that take a bunch of CPU power to decode like Canon's MXF and other formats. I even saw it a couple of times using CS6 and Arri RAW files.
Let us know if the purging everything clears up the problem.
If it doesn't you could always transcode the footage to a suitable 10 bit or better DI or render to an 16 bit image sequence. That's what I do with a lot of my keying work because I like the additional color depth and control and you can't beat image sequences for reliability.
Rick, many thanks for your clear and helpful answer. I had thought my next step was to export, although I had not thought to use image sequences. I'll also try the purge. Best regards.
Rick: here's an update.
Purging did not solve the all the green artifacts. I found that making identical duplicate Keylight effects on the footage did remove some of them (go figure). In one case, it took 3 copies of the identical copy of Keylight to avoid the green artifacts. I sidestepped the whole infuriating issue by first exporting the MXF files from FCP as ProRes, and then using Keylight in AE. No wonder I drink too much... regards.
Hi I am having this issue too and these solutions don't seem to have worked for myself.
We are finding random artefacts when importing the MXF file to After Effects and Premiere. The artefacts are not on the supplied video when we view them in VLC but they appear when viewing the source in AE. We tried exporting a Pro Res version from Final Cut Pro X but the same glitches appeared in FCProX too.
As a work around we have duplicated some frames over the top of the problem frames as some are split second issues, whereas some others are worse and can't be fixed by this method. We also found that during the fix new issues were being thrown up on the green screen. I have attached the artefacts that have been thrown up. We used this technique to key out the green screen;
The video we have been supplied appears to be MXF with MPEG-2 codec which as far as I know should be okay to import into AE?
If someone could offer some advice as to why this is happening we would really appreciate it. Client is fairly understanding but I know if this happens with another video we might have an issue : /
The artefacts issue that seems to be because of the file format...
Extra issue that shows up sporadically...