Jerky playback on v18 with change of scaling algorithm

#1

On v18, I’m playing a 720x480/23.98Hz h.264 mkv, decoding in software, with output resolution set to 1080p/23.98Hz.

If the upscaling algorithm is set to either nearest neighbour or bilinear, everything is okay; but if I select any other upscaling algorithm, playback becomes horribly jerky. CPU utilisation is quite low, so it doesn’t seem to be running out of CPU capacity (unless it’s mis-reporting that).

Logs: https://paste.osmc.tv/epanolecej

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#3

I suspect this would’ve been the same with v17.6.
Can you confirm?

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#5

Not talking about suspend – but rather playback.

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#6

Yes, sorry, got my threads confused. :man_facepalming:

It’s been a while since I tried using software decoding in v17, but I’m fairly sure I didn’t get jerky playback using other upscaling algorithms. I think I remember that lanczos3 went a bit wonky if you tried to upscale to 4K (possibly because the CPU maxed out) but it worked okay scaling to 1080p.

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#7

Having said that, I do also have a hazy memory of the image quality using lanczos3 (on 17.6) not being as good as I would have expected (to the extent that using hardware decoding actually looked better).

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#8

Lanczos3 won’t be possible at a reasonable resolution.

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#9

What about Bicubic? That’s exhibiting exactly the same problem as lanczos3 at the moment (and, again, neither behaved like that in v17.6). Anything other than Nearest Neighbour or Bilinear is broken in the same way.

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#10

Did they work on v17.6?

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#11

Lanczos3 was definitely not as badly broken as it is now. I’m fairly sure at least some of the others worked okay, but I wouldn’t like to say for sure that they all did - I likely wouldn’t have tried all of them for long enough to notice.

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#12

v17 did not use most of the “high quality” scaling methods for video output. It was a long-standing bug. v17 also didn’t use high-quality scaling methods to upscale the GUI…they were only used for down-scaling to store in the cache.

All the settings for scaling (including choice of scaler) is new to v18.

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