Fitfilm Stuttering During Transitions.

Howdy Gents.  I just wanted to mention a bug or at least an area for improvement I've noticed in hitfilm express 2017.  But first, system specs!  I may have gone a little overkill as I didn't want to have to re-encode my raw footage.  Because I'm a youtuber, quick throughput is fairly important, and I can have 1-2 hours of content that go into each video, re-encoding to a format that uses 1-2GB's per minute is kinda excessive, and while the video is 10-20 minutes long, there's only a couple points where hitfilm stutters.  Because of this, re-encoding isn't a very viable option.  Or at least one I was hoping to avoid.  That being said, I wanted to go a little overboard so that I wouldn't regret not going bigger.  So:

CPU  - AMD R5 1600

GPU- GTX 970


Anywho, the problem:

When you have two clips back-to-back on the time line and use a transition, if the clips are from 2 different files, then it plays fine.  However, if the both are from the same video file (ie you clipped a section out of the center), then the transition stutters a lot, as in I get about 5-6fps during the transition.  Originally I thought this was due to HDD limitations, but I tried putting the video file on the SDD with little to no noticeable change.  So it would appear hitfilm allots a certain number of cores to decoding the clip.  So when you're having to decode two parts of the same clips at once, performance suffers.  Another gripe I have is that playing a clip fast-forwarded causes stuttering as well, and I believe this is also due to the limit in core utilization for a single vidoe clip.  I don't claim to know much about what's going on behind the scene's in hitfilm and how it decodes everything, but if this is something that could be improved, that would be a game changer for me.


On this topic, as thoroughly beaten as it maybe.  I know the right thing to do is re-encode the footage, but I feel like there should be an option for folks that would prefer not to.  Like RAM preview in editor mode.  I know it's an option in composite shots, but I couldn't find a way to copy a whole sequence into a composite shot.  And most the time, I don't feel like recreating the sequence in a composite.  So instead I typically just export the specific part, preview, edit, and try again.  Another option is creating real proxies.  Or I'm sure there are other options I'm not aware of.


I really like hitfilm, and love the flexibility it offers, but I do have a small amount of frustration, as when I first got into editing, I referred to the 'hardware buying tips for running hitfilm' and now a couple PC's later, having a PC that is theroretically just as good if not better than the "lottery winners only" build, I hoped to be able to run it without problems.

I don't want to sound like I'm hating on hitfilm, as I truly am not, I tried multiple editors before sticking with hitfilm as I really enjoyed using it.  I am also very open to ideas and suggestions on my end, so If you've got some, please throw them my way!



  • I can't find the edit post option, so I just wanted to add, I meant to say "I believe this is also due to the limit in multi-core utilization for a single vidoe clip."

  • NormanPCN
    NormanPCN Posts: 4,376 Expert

    "When you have two clips back-to-back on the time line and use a transition, if the clips are from 2 different files, then it plays fine.  However, if the both are from the same video file (ie you clipped a section out of the center), then the transition stutters a lot, "

    This is a known performance problem with Hitfilm, when your media is in a high overhead LongGOP format. You are probably using AVC media. Even low overhead AVC will stutter with fully cached media. MPEG-2 is LongGOP but the decode overhead is so much power than the issue can often pass depending on CPU power.

    Hitfilm is thrashing the AVC decoder context. When both clips are from a single media file Hitfilm is using the same decoder context for both clips and the thrashing occurs. With separate media, Hitfilm has a separate context for each media file and all commonly goes as well as a single media stream.

  • WhiteCranePhoto
    WhiteCranePhoto Posts: 923 Enthusiast

    First off, your machine isn't what you think it is. The 900 series GPUs are... well, old. Their successors (10 series) are actually on the verge of giving way to their successor... 

    Second, get used to transcoding. Hard drives aren't particularly expensive, and transcoding doesn't take that long.

    Third, add a good proxy workflow to the HitFilm feature request list. The way that a proxy workflow SHOULD work is that you'd basically say "make some proxies for me, HitFilm" and it would crunch away for a while, then say "I'm done!" Then you work as if nothing has changed, and when you hit "render" HitFilm uses the original media to render, and you don't need to worry about it. A "clear proxies" option would enable you to clean up conveniently when you're done with that project.

    That's how the Resolve proxy mechanism works. It's brilliant, and it's shocking to me that it isn't more common, especially with today's monster codecs... though the higher end solutions do NOT have such a thing -- they're built with the assumption that no one using a solution that cost $120,000 would torture themselves by trying to edit with a consumer codec like H.264. :)


  • I had a fit seeing the name of this forum!

  • Zarod
    Zarod Posts: 13


    Any updates if this problem is been fixed?

  • Zarod
    Zarod Posts: 13
    edited April 2018

    @NormanPCN I wanted to ask technical support but currently if i render with OBS at 192 kbps Audio once i import it in Hitfilm it gets choppy during transition, even if rendered. I figured it out just now that i changed back to 160 and works like  a charm :)


    And another thing : apparently your settings for NVEC require more power and space to achieve the same level of quality than the setting i'm currently using. Tried using Handbrake with your setting that you wrote in another post and works fine. Currently using OBS for recordind and Handbrake after that seems the best method overall. 

  • NormanPCN
    NormanPCN Posts: 4,376 Expert

    @Zarod IF the audio bitrate is causing you performance issues then your machine is very underpowered.

    About NVENC, as I stated in my thread.

    "The low latency presets might be worth trying if Default has performance issues or the resulting effective frame rate is less than the recorded rate. High quality can be used if your machine can keep up. High performance is always CBR (constant bitrate output)"

    You might have to use the low latency NVENC presets if the Default profile causes performance issue during capture. None of this has anything to do with editing in Hitfilm. This is about smooth capture performance.

    Edit performance in Hitfilm will be related the video bitrate and the settings. The settings are covered in my thread. The bitrate is something you have to workout for yourself. Quality versus edit performance.

    If you are having edit performance problems you should look into transcoding to Cineform (Windows) or Prores (mac). The files will be 3-5x bigger than your AVC but the edit performance will be much better. Especially in transitions, which is the topic of this thread.

  • Zarod
    Zarod Posts: 13
    edited April 2018

    Thanks again @NormanPCN for the answer.

    these are my specs:

    Intel i7 2.6Ghz

    Nvidia Geforce 1060 gtx

    Are they underpowered?

  • NormanPCN
    NormanPCN Posts: 4,376 Expert

    @Zarod 2.6Ghz is probably a bit of a low clock for editing AVC media. Fast decode or not. I can't say for certain since I have personally only ever run at 4Ghz in Hitfilm.