Premiere CC 7.1 - Red frames in playback and export

Question

Having some problems after the 7.1 update.
In a variety of projects, on a variety of footage, we're experiencing random fully red frames (#ff000). Sometimes there are 1-2 frames in a clip, and occaisionally it's 80%-90% of the frames in a clip (this is less frequent). It has never been all of the frames of a clip.
This happens:
- On an undrendered timeline (you'll be watching an edit and you'll see a red frame - if you scrub back to it it'll still be there)
- On a rendered timeline
- In exports
Red frames that are visible on a timeline, are sometimes carried through to the export and sometimes not. Sometimes an exported file will display red frames that were not present on the timeline.
Red frames seem to be based on clips, not sequence frames. For example, in one of my exports, I had video footage with a lower third graphic over it. In one frame of the export, a red box appeared over the graphic, but the main shot was not affected.
This has happened to the following types of footage:
- .MTS (from C100)
- .MXF (from C300)
- ProRes 422 MOV
- ProRes 4444 MOV with alpha channel
Fixes that seem to work:
- If an export has red frames, re-export. Watch the new one like a hawk. Repeat until you get lucky.
- If a clip on a timeline has red frames, force a re-render via a Crop filter or similar
- Quit Premiere and reopen it
System/environment details:
- OSX 10.8.5
- Premiere Pro CC 7.1
- Mercury Playback Engine Software Only
- Often (always?) I-Frame Only MPEG sequence settings
- Much (all?) of the footage we've been working with has been on AFP shares via GigE with MTU of 9000
I haven't been able to confirm yet:
- Whether this ever happens with locally stored footage
- Whether this ever happens when Queueing to media encoder (rather than Exporting from Premiere)
- Whether changing to a QuickTime Desktop based sequence setting resolves the issue
Is anyone else experiencing this issue? It's frutstratingly un-testable, since it seems to happen at random. We'll continue to gather data points though and see if we notice any other trends.
Edit: Added additional system context

Answer 1

the error also appears with PRORES 422 files, but only after a certain amount of source data from prores 422 clips is processed / read
i made a test comp in AE with only one gigantic prores 422 source clip (8000 pixels x 1000 pixels @25fps) and the error first appeared at around 1500 frames read from the source file (equalling a few GB of source read and processed). after the red frames error appears once, the erroneous red frames appear more often but never in the same place when rendering the same comp several times)
i also made a test comp containing only a few full HD prores 422 clips (1920 x 1080, @25fps), there the error appeared only seldom (but still randomly). so it can be that a broader user base never experiences this erroneous behaviour at all.
i also made a testcomp containing about 40 full HD prores 422 clips (each 1920 x 1080, scaled down to 10% in size and distributed all over the comp so i can see them all at once). the erroneous red frames appeared within the first rendered frames!! obviously, many qt files had to be open and read in parallel, and so the error appeared from the very beginning of the rendering / export.
i suspect that the AE / PR applications open a RAM buffer for each open prores source file they need to read, and that this buffers somehow becomes compromised when it overflows and when buffer resize / buffer clear / flush operations take place.
of course i tested all sorts of RAM assignents for MP rendering (1GB per core, 2GB, 4GB, 6GB) and i rendered with several different settings of how many cores and ram should be available to other tasks. but the error always appeared. randomly.
--> fact in AE is, that nearly all MP renders / exports using prores clips as source files contained the bad red frames. when rendering without the MP option on (but of course up to 20x slower) so far i never experienced this error (of course always after fresh restarts once the error appeared)
PLEASE FIX THIS ASAP
mac pro 2011, 12 cores, osx 10.8.5, 64 GB ram, angelbird SSD, ati hd radeon 5770 1GB