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  1. Hi everyone,

    After years of using user-friendly software like DvdFab and HandBrake, I wanted to give a try at some advanced programs in order to achieve high-quality encoding of my dvd gems. And I have to say results with QTGMC deinterlacer are very impressive so far.

    But I'm concerned about my CPU usage with StaxRip 2.1.4.8-Beta (portable). It's very low, and it's very frustrating assuming the capacities of AMD R9 5950x.

    Do I have to tweak some parameters within the GUI or encoder options (x264)?

    Image
    [Attachment 56123 - Click to enlarge]


    Thanks in advance for any instruction, I feel very noob at this moment
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  2. Most likely you are not using prefetch function in avisynth scripts and thereby you are bottlenecked by single threaded qtgmc
    Last edited by Atak_Snajpera; 7th Dec 2020 at 07:25.
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  3. Yes, try adding prefetch(16) at the end of your AviSynth script. Maybe more.
    Last edited by jagabo; 11th Jun 2023 at 19:01. Reason: added "script" after AviSynth
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  4. Ooooh I see, glad my feeling was right!

    So it's in the filters list: Misc > MTMMode > Prefetch am I right?
    Is the value physical or logical cores related? I have 16c/32t processor.

    Many thanks anyway, I'll give a try on thursday
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  5. Prefetch is the number of threads that will be used. The "best" amount is somewhat unpredictable. Too many threads leads to more overhead keeping track of them and less locality of reference, leading to cache thrashing. In my experience (8c, 16th CPU) there's usually diminishing returns after 8 but it depends on the filters being used. And sometimes there's a single threaded filter that becomes a bottleneck so using a large number of threads doesn't help much.
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  6. Ok, so much better now: enconding at ~170fps for ~95% CPU usage. Value 16 for prefetch did the trick

    I ran almost 7 years a 4c/8t i7 4790, now I can have some fun again

    Thanks, have a nice end of year!
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  7. Hello,
    I have the same Problem. In the actual Staxrip-Version (2.13) there is no Option under "Misc > MTMMode > Prefetch". Where can I find it now?

    I've just found something under "Tools > Settings > Maximum Numbers of parallel Processes", but I think this is NOT the same option and just means, that Staxrip can manage that amount of Encodings at one time, right?
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  8. Member
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    Ah! I found it! In Staxrip v2.16.0, these settings are hiding HERE:

    Image
    [Attachment 71584 - Click to enlarge]


    AVS Filters > Insert > Misc > MTMode >
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  9. Member
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    OK! So, after adding Prefetch(8) (I have an 8-core CPU), nothing happend! I kept banging my head against Staxrip, but couldn't find out why I still couldn't get it to use the full CPU might to encode a single video, until I stumbled onto this webpage:

    http://avisynth.nl/index.php/AviSynth%2B#Multithreading

    It's really old information but it mentions one CRUCIAL thing: You must put Prefetch(8) at the very bottom of your AVS Filters, so that it is the last one! Once I did that:

    FULL CPU UTILIZATION, FINALLY!

    So your AVS Filters list should look like this:
    Image
    [Attachment 71664 - Click to enlarge]


    Good luck!
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  10. Originally Posted by higado2 View Post
    one CRUCIAL thing: You must put Prefetch(8) at the very bottom of your AVS Filters
    Yes. I said earlier:
    Originally Posted by jagabo View Post
    Yes, try adding prefetch(16) at the end of your AviSynth
    Oops, It looks like I left out the word "script" at the end of the sentence.
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  11. Member
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    Well no matter, now it's crystal clear for the next person!

    Many thanks for posting the solution in the first place!
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