This is my impression as well.
In yesterday’s project I needed to have twice my usual number of tracks, and twice as many clips. So there was a noticeable difference from my “usual”.
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Shotcut-Versions: Speedy v20.11.28 - Slow v21.01.16 - Unusable slow v21.01.29
Using these Shotcut-Versions with Windows 10 Enterprise from the portable zip file with a 20 minutes 4K-mlt-script is a pleasure to work with in v20.11.28 consider speed of GUI and moving the playhead. Proxy preview x 540p is fast and easy.
But using the same mlt-file with v21.01.29 is horrible slow and lagy. Each click just opening a menu like “Edit” or “View” takes a second or two.Tried version 21.1.16, too. It is slow and lagy and proxy preview is stop and go.
Just the middle from new and old version.
Loading the mlt-file is very fast in v21.01 and moving a clip from one track to another for ex. is still very fast, this task is very slow in the old version 20.11.
But its the GUI which is slow to pain.
Tried opening the same mlt-file at the same time in both versions, using taskmanager to switch between the versions of Shotcut. RAM usage is only 6GB from 16GB available. CPU usage is at expected levels.
As said, reading the mlt-4K-20minutes file is lightning fast in v21.01 and takes very long in v20.11. But when the file is open then moving the playhead in the old version is agil and fast. Moving the playhead in v21.01 is slow motion at its best. Both versions use the same proxy files x 540p, cause its the same open mlt-file.
My hope was GPU GTX1060 with 6GB would help and GPU usage may be improved. But to enable the GPU for proxy-computing or final video export does not improve the speed at using the GUI during work.
I think I read in the update hints that QT now is fully envolved in the GUI in v21.01. So my guessing is a problem there if other OSs than Windows 10 do not have this GUI performance loss.
Tried again with very small video and only two tracks. The new version is there faster than ever …
The longer the videeo the slower Shotcut? Other difference is the video slow in handling having no playlist. All clips are directly drag-n-dropped into timeline.
There is a known performance problem running multiple instances of Shotcut at the same time.
Do not do that for now! I know at least part of the reason: the database file that holds the cache of the waveform data and thumbnails - even if those are turned off. I need to rewrite that to not use a database. The first instance of Shotcut will open the database and lock it. The second or more instances will not only have access to the cache, it will keep trying to use the database in case it becomes available.
I think I read in the update hints that QT now is fully envolved in the GUI in v21.01.
The Qt library has always been fully involved in the GUI. What has changed is the versions and therefore the APIs. For parts of the GUI, we used a category of API called “Quick Controls.” After a few years, a “Quick Controls 2” API was announced and the old one deprecated. In the current version of the library (upgraded in Shotcut v20.10), the old API is no longer supported, but we were still using it but we saw the warning. That did cause some problems with some multi-screen setups. The solution was to start migrating to the new API, which we did in Shotcut version 20.11 but not completely. If that is no longer supported then certainly using both at the same time cannot! Also, in the next version of Qt, the old Quick Controls 1 API is removed. So, for Shotcut version 20.01 we completely migrated to Quick Controls 2. I actually expect that all this combined with new and improved Windows build system would actually improve things. Maybe it has for some. There were always some systems on which Shotcut did not work or work well. Of course, while not ideal, being pragmatic, I expect that when there are big changes like that it will not work for some and improve for others.
Hi, for a while a was using the daily built Portables and i kept reverting to 20.12.10, then 21.01.29 came out and even after reboots, 5 minutes on/off of (not responding) same with 21.02.15. I installed 20.09.27, dragging file in Playlist then to Timeline it is very fast “instantly” for me to be able to start moving along the timeline with my ShuttlePro in 5 seconds increment as fast as I can turn the wheel, I can not make it lag (with 20.12.10 I could reach a lag point).
The file loaded is a 3 Hours TvShow.ts 22.87GB
System under Windows 10 Pro with NoPageFile:
Intel i7-4770K CPU @ 3.50GHz 3.50 Ghz with 16.0 GB
With GTX1050Ti 4GB 768CUDA
I will keep that TvShow.ts until next Sunday then it will be replaced by another one.
I’ll be glad to help if I can.
Have a nice day
DenisT