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Author Topic: Thumbnail access/ display performance weakness  (Read 990 times)

rolf_eigenheer

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Thumbnail access/ display performance weakness
« on: February 02, 2021, 10:12:57 am »

My MS Surface Pro (5th Gen) runs well with a freshly imported library with 392,000 files. After the first slow scrolling through, the thumbnails are generated for the first 4000 albums. Scrolling using PgUp / PgDn resp. Cursor Up / Dn runs smoothly.

After creating around 90,000 thumbnails, the performance collapses. When holding the PgDn button in TheaterView, the screen remains blank. I have no idea how far I've flipped. Only after releasing the button does the page with the covers build up. Then I see where I am and can continue paging - blind again. The album artist/names are not drawn before the thumbnail is shown. Therefore it is possible to use a view with no existing thumbnails, but it becomes useless when many thumbnails are available.

The size of the database is not a problem for the computer. However, the thumbnail handling is disproportionately slow and becomes even slower as the number of thumbnails increases. It seems that there is no index for this.
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JimH

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Re: Thumbnail access/ display performance weakness
« Reply #1 on: February 02, 2021, 12:28:22 pm »

In Options for Tree and View, choose Build Missing Thumbnails and let it run.

You may be using a NAS or USB drive that is limiting performance.
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Hendrik

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Re: Thumbnail access/ display performance weakness
« Reply #2 on: February 02, 2021, 01:21:25 pm »

Thumbnails are cached in memory with a maximum cache size. If you scroll through your entire library at once, you'll likely flush the cache several times and thus thumbnails need to load from disc. This is expected behavior.
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rolf_eigenheer

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Re: Thumbnail access/ display performance weakness
« Reply #3 on: February 03, 2021, 01:49:14 am »

In Options for Tree and View, choose Build Missing Thumbnails and let it run.

You may be using a NAS or USB drive that is limiting performance.

Hi Jim. I used this option to build all thumbnails. This made the performance worse, not better.
As long as there are no thumbnails built, the page shows up immediatly. Instead of album covers, blue notes were displayed together with the artist name. This works fine, even when holding PgDn or CursorDn pressed continously. Every page is drawn and I can read the artist names while they fly by.
After thumbnails are built, I see an empty screen while scrolling fast. I have to release the PgDn key to see the artist names. They are shown after the covers are displayed.

As long as there are no thumbnails built, scrolling Artists is as fast as scrolling Albums. Therefore the database is not the limiting factor. But when thumbnails are available, displaying Artists becomes much slower.
The bottleneck seems to be the thumbnail handling. The problem is not the time it takes to load all the covers. The problem is, the drawing order.
When a next scrolling command is in the queue, the display procedure should be shortened. Instead of reading all fanned images, only one should be read. And if there is no time to read one single image, then just draw the name. Or show the current name as overlay. The user just needs a feedback how far he scrolled.

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rolf_eigenheer

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Re: Thumbnail access/ display performance weakness
« Reply #4 on: February 03, 2021, 02:30:26 am »

Thumbnails are cached in memory with a maximum cache size. If you scroll through your entire library at once, you'll likely flush the cache several times and thus thumbnails need to load from disc. This is expected behavior.

Seeing a blank screen while scrolling through my audio collection is not an expected behavior. Not for a paying costumer.

If software developer expect cache flush as a problem during scrolling, then it should be solved somehow different.
While scrolling from top down it is very likely, that every page requires new thumbnails to load. Since the thumbnail files (.jmd) are larger than the total amount of RAM, it is clear, that they cannot be held in memory. If continous scrolling requires that all thumbnails of a view are held in RAM, then they would have to be read once when entering the view. An image which shows fanned images requires the same size as one single image. Instead of holding my 50'000 album covers, only 7'000 fanned images need to be hold in RAM. This would be as little as 140 MB.
But even without caching all fanned stacks in advance, the problem can be avoided:

- The most important visual feed back is the current position inside the list. A text overlay with the current item would solve that.
- Thumbnail display gives a pleasent look. But for a page which is shown for less than 100ms there is no need to create fanned image stacks with individual covers. One single cover duplicated n times for fanning would be more than enough.
- Every thumbnail is available in smaller size too in a .JMD file.
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rolf_eigenheer

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Re: Thumbnail access/ display performance weakness
« Reply #5 on: February 05, 2021, 01:17:15 am »

By accident I found that scrolling with the scrollbar activates OSD and displays the name of the top left item. This is a exactly what I'd expect when scrolling with the mouse wheel or keybord (Up/Dn PgUp/PgDn).
@Matt: Would it be possible to enable that for the next release ?
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datdude

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Re: Thumbnail access/ display performance weakness
« Reply #6 on: February 28, 2021, 10:55:21 am »

I've noticed this problem too. I switched to a 4k OLED and now MC theater view is VERY slow when switching views with FANNED thumbnails in the top roller. Views without fanned thumbnails are instant. I don't have any anti-aliasing on. I turned off all of the extra graphics quality options in MC.

The other thing that impacts this is the size of the thumbnails. I prefer them large which causes the slowness. If I make them smaller, fitting more on screen, MC speeds up again, though still a little slow vs. my 1080p monitor. I think the 4k scaling with all of those thumbnails is just too much I guess.

If you could to turn off fanned thumbnails in Theater View, I think that would solve this problem!
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rolf_eigenheer

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Re: Thumbnail access/ display performance weakness
« Reply #7 on: February 28, 2021, 01:27:01 pm »

If you could to turn off fanned thumbnails in Theater View, I think that would solve this problem!

Fanned thumbnails are not the problem. When I choose a total scale (scale within Theater Mode  multiplied by scale of Win 10 display settings ) of < 200% there are much more thumbnails to display. But scrolling is faster compared to a 300% scale, where less thumbnails need to be displayed per page.
When total scale is >250% MC reads the cover art from the media file instead of the thumbnail cache.
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datdude

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Re: Thumbnail access/ display performance weakness
« Reply #8 on: February 28, 2021, 02:03:18 pm »

For me it’s not about scrolling. That is always smooth.  But when switching views in the roller menu, the views with fanned thumbnails have a noticeable hitch in them sometimes even several seconds before loading. All other views are instantaneous. If toggle the list view to something other than the standard grid tile view (without fanned thumbnails) the exact same view loads instantly. Flat grid views that are not grouped and thus no fanned thumbnails, also instantly load.

I can pretty much guarantee adding that option to disable fanned thumbnails in theatre view would help with performance!
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