Choppy playback with Audio Effects

So I have one 5 second clip pulled into into media and placed on the timeline. It is CineForm codec 10 bit YUV is a snippet that I exported from Hitfilm earlier.

If I add any sound effects to the clip performance goes to crap. I tried a small room reverb. Stutter. An equilizer. Stutter. Noise reduction. Stutter. Anything audio...stutter.

I think my machine should be able to handle this? I have an i7-6700 3.4GHz processor, Windows 10 build 1709, 32 GB DDR4, GeForce GTX 1070 GPU. SSD drive with one internal and one external (USB 3.1) 7200 mechanical drives. 

There are no other effects running at all..just one audio effect at a time to test. What am I missing (I know it's probably staring me right in the face)?



  • Oh..and CPU usage doesn't go over 20%. Nothing gets high, not memory usage, disk usage...etc. 

  • edited December 2017

    There is nothing for you to miss really. That the CPU usage does not go high during playback with the audio effect, and it is stuttering, often means the audio effect is single threaded. Some kind of bottleneck at least. While image effects are very friendly to parallel compute this may not be the case for audio.

    Unfortunately ram preview does not help with audio effects. Ram preview only buffers video.

    I just tried a WAV file 44.1 in a project 44.1, applied the small room effect and played and watched the basic task manager core utilization. 8 cores are being utilized, about 20% each. i7 4770k 4Ghz. No core is saturated. No big deal single it plays fine. My CPU is a bit faster than yours. Then I add an Equalizer with Small room. Hitfilm is unable to do this combo in real time. Not a single core is saturated. About 2/3s each core. It does not seem like a good performance. I'd like to see something saturated. This is obviously not I/O bound.

    Of course with this audio effect combo does any app make speed. I cannot comment since I've done no audio stuff like this.

    There is not enough granularity in the task manager graph to make any specific conclusions. Raw CPU speed does not seem to be the bottleneck. Something else is going on.

    What we can say is that performance is ehh and Hitfilm does not seem to be able to saturate any single CPU core before falling down performance wise. Saturate in my terms is not a full 100% but something close. 85/90+%.

    This is a bit of a common theme with Hitfilm. When it runs out of gas, the hardware still has some power to spare. Not that Hitfilm can't peg the hardware to the wall, CPU and/or GPU. I can easily set that up with video effects and media. There are far more circumstances in Hitfilm where HW performance is still on the table. This is true for all apps, but in Hitfilm the percentages are not in it's favor. Maybe a bit unfair to blanket statement that. A statistical observation. All of my experience is media/timeline and effects.

  • @NormanPCN Thanks.

    So either I have a bottleneck somewhere that I haven't found or it is an optimization issue with Hitfilm itself.

    I'm leaning towards the latter, as I run DAW software as well for kicks some times, and I can stack effect on effect in multiple tracks with no issues at all...heck, even with heavily processed tracks I can still play real time via midi on a software based synth with no lag.

    So I dunno. I noticed it a couple of days ago when I tried to use the eq on a track to remove a hiss that for whatever reason noise reduction refused to hear (that could have been user error though...I'm fairly new to Hitfilm). 

    Kinda sucks as it makes most of the audio tools useless to me. If you can't use your ears to hear the change....well....useless. 

  • edited December 2017

    Oh, it is definitely on the Hitfilm side. I would bank on that. That your 3.4Ghz CPU cannot handle a single audio effect, my 4Ghz CPU cannot handle two sample effects is frankly pretty bad. Not really something you can use.

    I did a quick test on Vegas with an EQ and a Reverb effect on the same media tested in Hitfilm. Those two effects do not even register any CPU increase beyond playback. The Hitfilm Small room is certainly Reverb but maybe something else as well.

    In Vegas I can even put 5 reverbs in with EQ and it does not register anything measurable on the CPU or GPU verses no effects.

  • edited December 2017

    @NormanPCN And for fun I just ran the same test in Hitfilm 4 Pro edition. It doesn't stutter or lag at all.

    I pulled in both small room and eq, adjusted eq, and hit play. Flawless.

    Same clip with the same source file, machine, runs in 4 and chokes in 6. 



  • Nice catch.

  • Ya I just created a ticket. Fingers crossed.


  • Express 2017 works better than HF6 was well. Still massive CPU utilization compared to the zippo utilization for Vegas.

    The EQ effect in Hitfilm wants about 11% of my CPU. One fully saturated thread. Small room wants about 30%. Approx three saturated threads.

    If FxHome can fix the regression then you can do some audio in HF. Maybe an effect or two depending on how fast your CPU is. But compared to Vegas and likely others, Hitfilm is going to run out of performance within an effect or two. Vegas is probably dozens of effects.

  • Aladdin4dAladdin4d Moderator
    edited December 2017

    I haven't done a lot with HitFilm's audio tools because HitFilm didn't have any when I first started using it and I invested a lot of money in the other audio tools I do have so by golly I'm gonna use 'em! Anyway noise reduction in particular is usually never intended to be a real time effect. Anything that takes a noise print for reduction will have latency problems. You can be getting as much as 35,000 samples of latency under the best of conditions. I have Izotope's Rx Advanced, arguably the best audio noise reduction suite on the planet, and it warns you when you're doing something not intended for real time playback. The Sony/Magix noise reduction plugin doesn't do real time either. The way to use it with Vegas is render the audio as a new take.

    EDIT: Also wanted to add that many, if not all, of HitFilm's audio effects are probably destructive like Audacity or Sound Forge as opposed to non-destructive like you see with VST effects in a DAW

  • Exactly. As I said above, I like playing with DAW's. Reason for example...I can easily have 12 tracks of music...some loops, some software instruments..with every track containing multiple effects. And I can still play LIVE AND RECORD at the same time on a software synth with effects added with no real lag.

    Now granted, Reason does not have to deal with video at the same time. But...when this happened with the 5 second clip that I posted about....Hitfilm was not being asked to do anything to the video except play it back. I had already built, rendered, and exported the video to use again (because it was a comp shot that was 100% rendered within Hitfilm...when I tried to edit sound everything crapped I exported into Cineform without finishing the audio and started a new project with the rendered clip to work on audio).

    I hope this is an easy fix for HF. It used to work right, and they beefed up the audio components a bit with this release. But as it is right now it is not usable for me.

  • @Aladdin4d I get that with noise reduction.

    But just throwing an EQ on a track causes a stutter on darn near every frame.

    Also..thanks for the destructive edit. I didn't realize that. I'm fairly new to video but oddly find myself putting stuff together as a job.The wife is a blogger/influncer/social media guru, and I am her tech...which means I've had to learn photography (halfway decent at that if I do say so myself lol) AND video. I tackled the still photography first, and I can now say that I am halfway decent at shooting and editing with Capture One and Photoshop. 

    Video is a different animal though. Some stuff translates...but the learning curve is still steep, and I am off topic.

    Bottom line. It works in HF4, but not HF6. At least on my machine.

  • @Aladdin4d "Also wanted to add that many, if not all, of HitFilm's audio effects are probably destructive like Audacity or Sound Forge as opposed to non-destructive like you see with VST effects in a DAW"


    Hitfilm's audio effects all work in the fly for me.


  • @NormanPCN What I mean is the audio data itself is being modified and what you hear is an audio render just like the video gets rendered during scrubbing/playback. Real time effects in DAW's don't do that. Instead they only alter the audio on the fly during playback and only become destructive when the audio is rendered for export. 

  • @Aladdin4d I don't feel that you're accurately using the term "destructive" in this context.  Programs like Audacity are truly destructive because they literally modify the original audio data.  Once you apply Echo, for example, that echo is baked into the data.  You can undo if the session is still open and you haven't saved the file, but once saved, the original is permanently changed.

    HitFilm audio effects work just like video effects, and just like effects in a DAW.  They're calculated in real time during interactive playback.  DAWs don't "become destructive" during export.  They simply generate a new audio file with the effects applied.  The original is never modified, just like the original elements of a HitFilm project are not modified permanently by exporting.

  • @jsbarrett I believe you are correct. the audio effects work just like video effects meaning they have to be rendered to get the result and I don't mean the final export. You are rendering just scrubbing the timeline. A DAW doesn't operate that way. Effects in a DAW modify a playback signal. This is a key distinction. HitFilm is spectacularly incapable of modifying a playback signal. Any change anywhere halts playback. You apply an effect but you can't hear the result until some kind of render is done altering the source data in the pipeline. HitFilm's method, fundamentally modifying the data in order to produce a result, is a destructive method even though the program itself is a non-destructive editor. Audacity and Sound Forge are non-destructive editors as well but they both use destructive methods to produce a result. 

    Let's go back to a DAW where we're modifying the playback signal. The original audio data remains unchanged throughout the entire pipeline. The only time the original data is actually modified is when you export. At that point, things change from modifying a playback signal to fundamentally altering the original data. The difference is essentially the same as using grade/adjustment layers vs applying effects directly to a layer. When you apply an effect directly to a layer, the original data is then fundamentally altered in the pipeline. If you add grade layer and drop the effects on it instead, then the underlying data remains unchanged throughout the pipeline. The first is destructive, the second non destructive. 


  • That's a level of destructive discussion that's beyond anything I've ever seen.  I've only heard the term used to separate apps like Audacity from ProTools, where Audacity is frequently described as destructive and ProTools isn't.  What you describe makes sense now that you've broken it down, but using "destructive" in more than one context in the same application feels confusing to me.

  • @jsbarrett It is confusing and why in the heck they didn't choose different terminology is beyond me but what I just described is exactly why Audacity is called destructive, even though it never changes the original file making it a non-destructive editor, and ProTools isn't. It gets even more confusing when effects in a DAW can be applied destructively and non-destructively at the same time! You can do something like destructive noise reduction on an event that's on a track that has non-destructive compression that's assigned to a bus that has non-destructive reverb applied. This is some documentation from Sonar. Unfortunately Gibson just killed Sonar off a couple of weeks ago but the docs are good and still up. X2&language=3&help=Mixing.24.html

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