P: Video Cache is out of control

Jury - This isn't about importing videos - this is about LR scanning your entire disk and making copies of each video it finds, then deleting them - completely ignoring the cache max size.  

This is not a feature. This is a bug.

I understand your frustration but sarcasm sends the wrong message to product management. 

This is a bug.  

Say it with me...

This is not a feature. This is a bug.

Unfortunately, it's not a bug, it's an (unnesessary) feature.

Nobody in sane mind won't edit video in Lightroom, but The Marketing told that video import will boost sales.

And here we are.

Yep, I've read that in former posts. 

I don't know how much you know about the software industry so forgive me if I'm covering old ground here.  The job of any support person is to work on a problem until there is a workaround and then file a bug.  In the bug, they list the workaround and Product Management/Engineering assess each bug and assign it a priority.  Bugs that have "workarounds" are given the lowest priority because... well... there is a workaround.

This isn't a minor annoyance with an easy workaround. 

This is a bug that will impact a high percentage of LR users (potentially millions of users), and which causes significant, and unnecessary, wear and tear to their hardware.  And many of those people won't ever know it.  

A headline like that could be very damaging to Adobe.

That is the context that Product Management/Engineering need to see this bug under - not that it's just some annoyance with a workaround.

sigh
I delete Dynamic Link Manager every time I upgrade or install Lightroom.
That's the only workaround here.

If it runs while dynamiclinkmediaserver.exe is encoding some of the files, the deletes of the files will fail.  This will only work if dynamiclinkmediaserver.exe has already completed copying files into the cache already.

Here we go again...

Affected Lightroom Version: 7.0.1  (LR Classic)
Computer:  Surface Pro 3
Computer Disks:

• C: 256GB SSD; system disk
• 😧 128GB Micro SD card in the built-in SD card reader; disk containing videos organized in folders by genre

LR Video Cache settings:

• Limit video cache:  Checked
• Maximize Size:  3GB

Issue Description:

Copies of videos from 😧 drive are added to the LR video cache directory when a user tries to import images.  This inevitably ends up filling up the system volume (C:) requiring manual intervention to delete the cached files, as the video cache size limit is not honoured.

Video Cache Folder: C:\Users\***** \AppData\Local\Adobe\Lightroom\Caches\Video\Media Cache Files

Steps to Reproduce:

1. Per above configuration, copy video files onto Micro SD card and put into card reader
2. Create directory c:\windows\temp\_deleteme_
3. Copy some large files (in excess of 5 GB) into c:\windows\temp\_deleteme_
4. Open Lightroom CC Classic (7.0.1)
5. Click Import
6. Windows Explorer: Open video cache directory; files are being created, including copies of the videos themselves (as CFA files - some of which are several gigs large)
7. CMD Prompt:  tasklist | find "dynamiclinkmedia" ; this shows that dynamiclinkmediaserver.exe is running.  
8. Click Cancel
9. Click File / Exit  (close LR)
10. Windows Explorer:  Video cache flies are still being created and all of the videos are being copied into the cache
11. Task Manager: Sort processes by Disk and see that dynamiclinkmediaserver.exe is doing 100MB/s or more of disk activity - WTF?  LR is closed...
12. Wait until disk fills up; sometimes, windows will tell you that your disk is full
13. Monitor disk space; it drops down to about 128KB free, and then it appears to delete a file from the video cache to make more space for the next file.  Therefore, the process is thrasing writes to my SSD disk (thereby reducing the MTBF of it, effectively costing me money!)
14. Delete the files from c:\windows\temp\_deleteme_; dynamiclinkmediaserver.exe consumes all remaining disk space with more cached files
15. Monitor dynamiclinkmediaserver.exe until it dies (and the disk stops thrashing).  In my last test, when it was finally done, I was left with 31.2 MB free on C:
16. Start Lightroom; wait 5 minutes - the video cache is eventually cleared (unless there is a hung dynamiclinkmediaserver.exe process, which does appear to happen sometimes).

Issue Details:

There are so many different things going wrong here it's amazing.  They are as follows:

1. LR starts caching any files that are on the SD card immediately, even though I have not browsed into any directory that holds a video (they are all in subfolders).  I'm presuming that this is because 😧 is in a card reader and, for convenience purposes, card reader/external disks are displayed first because that's how many people get photos into their systems.
2. dynamicmedialinkserver.exe does not honour the "LR Video Cache Size Limit" of 3.0 GB that I've set in Lightroom.  I don't care that LR deletes the cache the next time that it starts (provided that dynamiclinkmediaserver.exe has not hung)
3. Adobe software is scanning and making copies of my files WITHOUT MY PERMISSION.  It should not be copying the videos.  I can understand LR wanting to make thumbnails of the videos - but I DO NOT GRANT ADOBE SOFTWARE PERMISSION TO PROACTIVELY SCAN MY DISKS FOR FILES AND MAKE COPIES OF THE FILES THAT IT FINDS
4. Adobe software is actively decreasing the MTBF of my SSD disks because it is making unnecessary writes to my SSD.  I am not alone here - using SSD's for system volumes is now a ubiquitous configuration and so Adobe's software is actively causing unnecessary wear-and-tear on it's customer's hardware.  This happens in two ways:  1)  By filling up the disk, Adobe software is performing at least one write to every remaining sector of the disk.  2) By filling up the disk, it reduces the pool of sectors that other programs can write to, thereby more rapidly decreasing their MTBF
5. Adobe software is thrashing both my CPU and my disks with unnecessary writes, causing slow performance impacts to other software on my computer.  Adobe software is, effectively, performing a denial of service attack on my computer.  This happens even AFTER I have closed Ligthroom!!!!!
6. With legislation increasingly focusing on data protection and end user privacy, having programs that indiscriminately scan users disks for files is going to be an increasingly dangerous legal position to be in - not to mention that it is clearly antagonizing your user base.
7. !!!!!ALL OF THESE THINGS HAPPEN EVERY TIME I USE LIGHTROOM!!!!!

Bugs like this have presented themselves in both Ligthroom and Premiere, going back as far 2014 (and possibly earlier).  The first post, alone, in this thread is over two years old. Come on guys, this has gone on long enough.

To date, I have not seen a single good explanation, from Adobe, as to why your software is performing a denial of service attack on my computer and why your software is actively reducing the effective lifetime of my hardware.

Adobe has clearly made a bad architectural decision and has implemented a very destructive process.  I can forgive bad architectural decisions (being an architect, my bad decisions have cost companies millions of $ over the years).  But this one has gone on for long enough.

!!!!!!!!!!!!!! PLEASE STOP CACHING VIDEO FILES !!!!!!!!!!!!!!
!!!!!!!!!!!!!! PLEASE STOP CACHING VIDEO FILES !!!!!!!!!!!!!!
!!!!!!!!!!!!!! PLEASE STOP CACHING VIDEO FILES !!!!!!!!!!!!!!
!!!!!!!!!!!!!! PLEASE STOP CACHING VIDEO FILES !!!!!!!!!!!!!!

Quite frankly, if someone were to contact me saying that a class action lawsuit against Adobe were underway seeking damages for this bug, I would add my name to the list in a heartbeat.

Classic is much improved in some areas, particularly thumbnail and preview generation.

Video is, if anything, worse. It's status quo for the dynamiclinkmediaserver - it still seems to respect the new cache limit, at least between sessions. But performance loading large videos is poor and I've seen a few glitches, like failing to read .mov files until I restarted LR. Also, video display still consumes massive amounts of memory.

My guess is that the overall strategy is still just completely mismatched for the application. Pre-Classic, cached video files were uncompressed, making them ridiculously large on disk and in memory, and that doesn't seem to have changed. That might be useful for a video editor, but it's useless for LR. It would be far better to create a lo-res cache file, perhaps using just keyframes, with full audio but minimal video content.

There is a new version, "Classic," that improves performance in a few areas, particularly previews and the grid view.

I'm not sure if it changes anything about the Dynamic Link Server behavior though. My guess is not.

I just spent ages recovering from a full system C: SSD drive. Turned out to be this problem.

In preferences, Lightroom Cache is set to N: - and video cache is set to 3G.

Video cache on C: = over 60G 😞

Two years! Is there any development work happening on Lightroom, other than new lenses and mobile stuff - in which I have no interest?

Things seem to be at a standstill - and I'm paying out monthly.

Should I be looking elsewhere for my photo editing? 

Not impressed, not impressed at all. 

Many thanks for this - very helpful for all sorts of things.
One question - what happens if this runs when Lightroom is open and using this cache?