More cores..., what will happen?


Short question…, isn’t it?
But what is the answer? :smile:

I have currently the I3-6100 (2 cores, 3,7 GHz), what will happen with e.g. an AMD Ryzen-5-2600 (6 cores, 3,4 GHz up to 3,9 GHz), or maybe an AMD Ryzen-5-3600 (6 cores, 3,6 GHz up to 4,2 GHz).
Will I have a smooth playback in the source player, where the I3 has, more or less, stutter? E.g. with three tracks, two times blend mode and ‘ROT/SCALE’ and ‘Simple Chroma’…

Can I have a ‘Yes’…? :slight_smile:

BTW: Just had again that “buffer stutter”.

Best regards
Earlybite (who is really suffering)

Does this go some way to answering your query?

No, this says not really anything really… :slight_smile:
What ‘bottlenecks’, what deficiency?
I need something to build on it!
And if ‘frame-dropping’ (Realtime == checked) is enabled, then there is no multiple core use? And if, then there is no diefference between a 2 core and and a 6 core CPU?

Did you read the whole post, or just the extract shown here? The extract is the bottom line, i.e. under certain circumstances multiple cores are used, but you should read the whole post, not just the bit taken out of context.

It is the whole post…, or do you mean the whole thread?

I mean that you should read the whole thread, not just the bit taken out of context.

But it’s still not clear to me, if there is an improvement, if I use 6 cores instead of 2 cores (with h264)…, with e.g. 3 tracks:
1 track with BlendMode
1 track with ROT/SCALE, Nervous, Chop, Blend Mode, Chroma,
1 track with Only Color, but with Color Gradient

It’s not clear to me either. I personally don’t know how Shotcut works “under the hood”, for that you probably need a direct answer from Dan. He did put an item on the FAQ:

That says:

Shotcut’s engine (MLT atop FFmpeg and other libraries) uses multiple CPU cores/threads for:

  1. decoding video on many (most?) video codecs
  2. image slice-based multi-threaded processing in some processes
  3. frame-based multi-threaded image processing in many processes
  4. encoding video when not using the hardware encoder on most video codecs

When any of the above is not enabled, a bottleneck is introduced. Some of these are minor and others major depending on the weight of the operation.

Shotcut’s interface - in addition to the main UI thread - uses multiple background CPU cores/threads for:

  1. generating video thumbnails
  2. generating audio levels for waveform display in the timeline
  3. the engine itself (see above)
  4. sending video to OpenGL for display
  5. exporting

If I’m using ‘Realtime == checked’, I have all 4 CPU threads active, but only between ca. 25% and 85%.
If ‘Realtime == unchecked’, I have all 4 CPU threads with ca. 90%.
“But”, in that example, I have more then 4 heavy filter, where, and AFAIK, the CPU swaps/changes the work on the filter.
And I’m wondering if there will be an improvement, if a CPU can use 6 cores (12 threads)…

My pers. “main thing” is, that I will take money in my hand to upgrade extra for this…, and if there would be no improvement, I would be very disappointed.

Details are missing because there are many factors that change over time. You need to study the source code to know more. I am not going to try to enumerate everything when the source already does it and would be a waste of my time.

I really cannot understand that it seems to be impossible to give a ‘Go’ or not…,
yes, with 6 cores (12 threads) there is an improvement (to a 2 core/4 threads CPU ) , or not.
I mean there is even given a minimal requirement for to use Shotcut…

I have a headache now… :slight_smile:

I make videos, or I write to make videos. Both at the same time isn’t possible for me… :slight_smile:

But, how about to increase the buffer, maybe up to 600 frames? Then it would take maybe some seconds to start, but you will have 10 seconds (at 60 FPS) a smooth replay?
Only an idea…

Best regards

I’m running an AMD Ryzen 7 8 core processor on a Gigabyte Aorus Elite B450 mobo with a Gigabyte GTX 1050ti 4Gb graphics card and there are no problems using Shortcut.

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