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Rendering Project seems to only use 1 core

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Mon, 02/18/2013 - 11:43
#1
bazsound
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Rendering Project seems to only use 1 core

I noticed that kdenlive was taken alot longer to render project, but i just thought that was down to the render profile i was using (youtube optimised 720p) the video quality is way better than when i used openshot.

But i looked at my system processes and it seems that melt only seems to utilise 1 core as it sits at 104% cpu usage, and both my cores never stay at 99-100% as openshot did when it was rendering.

a 2 minute video (source files are quicktime movie format at 720p quality 60fps) a couple of title clips, there are quite a few source clips loaded but these are cut down to short clips, pretty much not really using any transitions except for the end where it fades out.

takes usually 25 minutes to render.

Is this normal? or is it possibly to configure melt run at full capacity of my system like openshot did.

with openshot, there was no way i could do anything else on my computer.

kdenlive i can watch a dvd while it renders or browse the web.

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Mon, 02/18/2013 - 13:41
#2
DiveO
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Re: Rendering Project seems to only use 1 core

Did you explicitly select to use multiple cores? There's an option in Kdenlive, either settings and/or render settings. Make sure that there is more than a single core enabled. So far I had never any issues on my quad core i5 system.

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Sat, 02/23/2013 - 18:53
#3
bazsound
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Re: Rendering Project seems to only use 1 core

i couldnt find anything relating to cores in kdenlive, and render settings just brings up all the profiles and what the terminal command is for those profiles

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Sat, 02/23/2013 - 19:17
#4
yellow
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Re: Rendering Project seems to only use 1 core

Its on a per project basis, so look in project settings.

**EDIT** I don't know what I was on when answering this query but it must have been strong. Totally wrong answer please ignore.

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Sun, 02/24/2013 - 04:58
#5
ttguy
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Re: Rendering Project seems to only use 1 core

Is this different to the "Encoder Threads" http://userbase.kde.org/Kdenlive/Manual/Project_Menu/Render#Encoder_Threads in the Render dialog ??? and different to the "Processing Threads" under http://userbase.kde.org/Kdenlive/Manual/Settings_Menu/Configure_Kdenlive... Settings Menu>Configure Kdenlive>MLT_Environment

Or does threads = cores in this discussion?

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Sun, 02/24/2013 - 15:31
#6
yellow
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Re: Rendering Project seems to only use 1 core

For encoding, with single non multithreaded encoders, then one thread per core, so a dual core could use two encoder threads, 4 core 4 threads etc.

Processing threads, I'd assume is more to do with other calculations like color effects, processing, even decompressing a codec in order to recompress it at render time.

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Sun, 02/24/2013 - 22:11
#7
ttguy
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Re: Rendering Project seems to only use 1 core

So you are saying that if a user wants to use both cores on a dual core machine they should specify 2 in the "Encoder Threads" option http://userbase.kde.org/Kdenlive/Manual/Project_Menu/Render#Encoder_Threads in the Render dialog ?

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Mon, 02/25/2013 - 00:37
#8
yellow
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Re: Rendering Project seems to only use 1 core

Yes, certainly works for me, 4 cores, 4 encoder threads, full utilization.

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Mon, 02/25/2013 - 10:46
#9
ttguy
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Re: Rendering Project seems to only use 1 core

So I had never looked into this. I have a Intel Pentium D E5300 2.6Ghz Dual Core processor (nothing flash).

And I just decided to look at CPU usage while rendering with 1 thread selected for "Encoder Threads" (my default setting and what I have been using for 3 years) and I find that both CPUs are hitting 90-100% as it renders. Which is not apparently what others in this thread see.

So I would say you don't have to explicitly tell it to use 2 cores.

My Processing threads option is also on 1

Rendering with 1 or 2 "Encoder Threads" under my setup makes no difference to the CPU usage or the time taken to render.

> 4 cores, 4 encoder threads, full utilization
And 2 encoder threads = 100% utilization on 2 cores and low utilization on the other two ??? Have you tested ?

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Mon, 02/25/2013 - 10:51
#10
yellow
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Re: Rendering Project seems to only use 1 core

Yes, I see that two cores fully used, two very low for other OS tasks I'd assume.

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Mon, 02/25/2013 - 13:09
#11
ttguy
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Re: Rendering Project seems to only use 1 core

Hmm. Well aint that interesting ?

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Fri, 03/01/2013 - 15:02
#12
bazsound
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Re: Rendering Project seems to only use 1 core

yeah i thought that threads maybe related to cores, i tried 2 no change.

Im running Ubuntu 12.10 with kdenlive 0.9.4 (not from the ubuntu repositary)

AMD 64 3600 dual core cpu at 2ghz.

As i previously said, openshot uses both cores maxed out, and the computer is as expected. cant do anything else till its done.

With kdenlive, i can still use the computer and dont really notice too much that its render, can browse websites, watch videos, even playback DVD's so im sure this is having a serious impact on render times. A couple of my projects have taken upto 50 minutes to render 3-4 minutes of video

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Fri, 03/01/2013 - 15:16
#13
bazsound
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Re: Rendering Project seems to only use 1 core

hmmm i just tried this again, set it to 2 threads and check my cpu usuage, its now using close to 100% for both cores and jumps down a bit now and then. My estimated render time seems to have jumped down a bit, though i wont know the real render time unless i let it run.

But it does seem to be rendering faster i think.

weird.

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Sat, 03/02/2013 - 01:11
#14
ttguy
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Re: Rendering Project seems to only use 1 core

Well the plot gets even thicker then doesn't it ??? !!!

Yellow adjusts the threads and gets immediate joy with respect to core usage.
I adjust the the threads and it has no effect - I get both cores used no matter what thread setting (but how often do I check core usage during rendering? Essentially never !)
bazsound adjusts the threads and sometime he gets both cores and sometimes not.

Gotta love computers some times !!!!

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Sat, 05/11/2013 - 02:49
#15
Spatry
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CASE STUDY Kdenlive rendering with MLT framework

Quad core rendering was something that has been really bugging me... I had rendering problems (artifacts with multi-threaded MLT), but could not duplicate them in this case study.

http://www.youtube.com/watch?v=hvUFnnYAgRg

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