With the new MTP support I have to choose between:
No Opus MTP support but fast and instant thumbnail support
Opus MTP support (which is great) but some inconsistent Folder Tree behaviour and terribly slow thumbnails
My Folder Tree Preferences settings are:
Preferences - Folder Tree - Options - Start Folder Tree at > Computer
Collapse non-selected branches = DEselected
When I attach my Canon Camera it appears just below the other drives. When I manually expand the folders
below 'Canon PowerShot A2000 IS' and select the folder '100CANON' in the folder tree, i don't get the
new MTP support functionality, which is normal (I think) and opus shows small thumbnails instantly:
When I don't expand 'Canon PowerShot A2000 IS' and just click it in the folder tree, the tree collapses automatically
and suddenly starts at 'Desktop' (collapsed) and I get the new native MTP support in the file display. This just doesn't
feel 'normal' and consistent, because the new MTP support doesn't respect the Folder Tree Preferences settings:
When I click the 'Verwisselbare opslag' folder in the file display and enable thumbnail mode (with new Opus MTP support),
I have to wait for ages before at least some thumbnails are displayed:
The new/beta "native" MTP support doesn't support the folder tree yet:
"Please note that due to the beta nature of this release, some MTP related functions are not yet implemented or complete (such as context menus, folder tree support and secondary file commands like SetAttr)."
Could the thumbnail speed difference be due to caching?
I now tried it with Thumbnail caching ON (caching was off) and the new native MTP support:
When I wait until all thumbnails are generated, the next time I navigate to the Camera I don't have to wait that long
(because the thumbnails are cached, of course), but it's still considerably slower then in Windows Explorer (instant thumbnail view).
But the problem is there again when I take new pictures with the camera. And I don't keep the photo's on the camera, so Thumbnail
caching doesn't make much sense for my camera: I just plug the camera in to copy (and delete) the new photo's
BTW: Also thumbnails for new photo's are shown / generated instantly in Windows Explorer
It takes Opus 3 minutes (!!) to generate 18 thumbnails (photo's on camera are approx. 4 MB)
Wow, Jon, this is just magic (to me). When Opus only uses 1 thread the problem is (almost) solved!!
It's still slower than in Windows Explorer, but Opus gives much better and larger thumbnails.
So it has probably something to do with the number of threads being used?
MTP has the limitation that only one file can be read at one time, when you have multiple thumbnail threads Opus will be trying to read from multiple files at once which means they are being continually open and closed as the threads "fight it out".
MTP supports a separate thumbnail data stream for each object, and this is what Explorer must be displaying. The thumbnail stream is a lot smaller than the real file and so will load much quicker but obviously is lower quality.
The solution to #1 is going to be to limit MTP to one thumbnail thread irrespective of the Prefs setting; we don't currently have a way to do this but I'm sure a solution can be found.
For #2 we could either do as Explorer does (and use the thumbnail data stream if there is one), or make it a Prefs option which one is used.
