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Comment prevent Explorateur Windows from lently reading fichier content to create metadata?

ayi

We have directories containing hundreds of video files. When using Explorateur Windows (Windows 7 64 Pro) to browse and rearrange these directories, Explorer slows down to an unusable level, uses gigabytes of RAM, and pre-empts or slows other programs (such as Media Center) from using the same disk while this is in progress.

This is accompanied by a very slow-growing green bar in the Address slot.

What Explorer appears to be doing is reading the video file content to produce thumbnails, or obtain other metadata. This is not useful for our purposes, so we'd like to disable this behavior. Comment fonctionne one do that?

These threads may be related:

Superuser Prevent Explorateur Windows from trying to extract metadata. [Explanation added 2014-04-11] This solution disables le registre's listing for a PropertyHandler for a particular filename extension. This could be useful, but is a little drastic -- would disable display of properties in Explorer for all directories, not just problem ones. (See more discussion in the answers.)

Superuser: "Sorting by Date - Very Slow" : The 'Date' column attempts to get EXIF data, and is distinct from the filesystem 'Date created' and 'Date modified' columns.

Microsoft: "Explorer - sort by date very very slow"

2014-04-14: Summary of suggestions and findings

Je pense at this point we're well satisfied with the answers, and remaining symptoms are unrelated to Explorateur Windows. So, herewith a summary of suggestions and a few other things we learned.

General considerations

Disk wake-up: Initial slowness when accessing a disk after a long period of disuse may be attributable to the disk having gone to sleep.

Disk errors: Obviously if there are hardware errors which compel retries, cela va gravely slow down Explorer and any other program.

Disk contention: Other programs performing intensive activity on the same drive will obviously contend with, and slow, Explorer's attempts to display a drive's contents. If Explorer needs to read only the directory, then impact may be minimal, but if Explorer also needs to read each file for metadata, then contention problems will be greatly magnified.

Disk contention from anti-virus software: Explorer's attempts to read metadata may prompt AV software to read and OK each file first. Consider disabling AV for trusted type de fichiers (par exemple, wtv files saved by Media Center).

Explorer settings

Disable display of thumbnails: "Organize" → "folder and search options" → "view" → put a checkmark in "always show icon instead of thumbnails" → press apply and close.

Disable gathering of video-specific metadata: Culprit folder → "properties" → "customize" → under "optimize this folder for:" ouvrez le drop down menu et choisissez "general items" → place the checkmark in the box under the drop down menu at "apply to all subfolders" → press apply and close.

Disable even more the gathering of video-specific metadata: In a culprit folder's "detail view", remove any columns based on video file metadata not in the système de fichiers's directory information. This includes the Length (duration) column, and also the Date column (based on video metadata, and distinct from the système de fichiers's "Date created" and "Date modified" columns.)

In le registre

Disable "Property Handlers" for video filename extensions (such as wtv, mp3 etc). This, of course, would apply system wide, not just for particular directories. Can be accomplished with RegEdit, or with 3rd party program ShellExView. (See Answers for details.)

More on thumbnail and other caches

We noted that after disabling thumbnails and metadata, when we re-enabled them, performance was speedy. (Ie: The green bar of slowness didn't return.) This suggests that the changes did something regarding the thumbnail cache(s), perhaps deleted them and later rebuilt them. Turns out that par défaut Explorer saves thumbnails in each directory (in thumbs.db) and also in the user's AppData\Local\Microsoft\Windows\Explorer directory in a set of thumbcache*.db files. It's possible these get into a bloated or otherwise slow state, and deleting them might prompt faster operation.

Not known (by us) is whether Explorer caches any other metadata info (such as Length, Date, Location, Protection and so on).

Other interactions

Not attributable to Explorer per se, but potentially useful clues.

We noted in Gestionnaire des tâches > Resource Monitor that Media Center was performing bad behavior that created beaucoup de disk activity: A media center component, ehrec.exe, would endlessly cycle through reading a few k of data from a particular set of video files -- on one drive, about 200 video files. It is as though Media Center is unable to complete reading metadata from those files, and just keeps trying to read files for which it doesn't have complete metadata. These files seem undamaged as far as the système de fichiers is concerned (can copy without problems). When we asked Explorer to display directories on this particular disk, conceivably Media Center's activity competed for disk access time. We disconnected this drive for other tests.

Thanks to all respondents.

ayi

FINAL MISE À JOUR :

OP has summarised all his findings completely and concisely in his question post. Je vois no reason to delete my suggestions, but i recommend you read his post instead of mine si vous êtes for a quick solution to your problem.

Vous devriez try two things:

In Explorer, cliquez sur "organize" -> "folder and search options" -> "view" -> put a checkmark in "always show icon instead of thumbnails" -> press apply and close.

Now faites un clic droit sur the culprit folder -> "properties" -> "customize" -> under "optimize this folder for:" ouvrez le drop down menu et choisissez "general items" -> place the checkmark in the box under the drop down menu at "apply to all subfolders" -> press apply and close.
Cela va apply the new folder view settings to the chosen folder and all the subfolders which are contained within.

I am german and thus have a german version of windows, so maybe some of those options above are translated slightly differently, but vous devriez be able to find them nonetheless.

Mise à jour 1:

Je pense you are à droite track with the metadata. Depending how the videos are encoded, the metadata could be either at the beginning, at the end, or even somewhere in the middle (which is rare, though). I am guessing that those video files were encoded with some unusual properties (you probably produced them yourself?) which makes explorer read in the whole file from beginning to the end to extract the metadata, which obviously takes a while if there are many big files in the folder. J'ai seen explorer read the full length of a giant exe file to display the embedded icon at the end.

So, i think you have it figured out there, identifying and disabling the columns which need to extract metadata from the view in explorer (together with the disabled thumbnails) should obviate explorer's need to read in those files, which should solve your problem.

Columns vous devriez probably not use are something like: date taken (as mentioned in one of the links you posted, date taken is very differently from the creation date of the file), length, resolution, location.

Columns vous devriez be safe to use would be attributes which can be read directly from the directory of the filesystem like: file creation date, file modified date, size, type de fichier.

If you indeed need for your sorting some of the attributes which should be disabled, i think that maybe the most practical solution would be to look for an alternative file browser, et cochez if it handles the situation better. You could then use explorer like you are used to normally, and use the alternative file browser to handle your video folders.

You also have the possibility to perform many basic file-oriented operations from your built-in ligne de commande interpreter cmd, it doesn't care about metadata and can be a simple and efficient tool for copying, moving or deleting files and folders. You could then even automate things by using batch files. This is most probably not the solution you search for, though, since cmd doesn't even have a graphical user interface.

Mise à jour 2:

Je viens de read your second update and i am happy to read that your problem seems resolved (for now, au moins). Maybe it really was just a matter of the thumbnail cache getting overcrowded. I could imagine those thumbs.db files getting bigger and bigger, if you move files from folder to folder frequently. I suspect it actually keeps a thumbnail in that cache file for every file which ever was in the folder. Maybe there is some sort of garbage collection mechanism for those files, too, but it failed in your case.

So, if you were moving video files from folder to folder en masse, and always using the same folders for that (eg. not creating new ones) maybe we have found the source of your problem...

If your system shows the same symptoms again in the future, you could just try deleting the thumbnail cache.
For that you need to:

"windowskey + r" -> input "cleanmgr" and press return -> choose the drive where the video files are on (only if you actually have multiple drives/partitions) -> choose "clear thumbnail cache" or something like that -> run cleaner