Lag/Stuttering between transitions

I am  new to video editing (did some small things in the past) and I have following problem with HitFilm Express 3.

When I select a media clip and cut this clip into several parts, where I delete some unnecessary video in between, the transition between the two cut parts stutters on playback. This is very annoying to review while editing. Between the transitions the video itself plays very smooth.

Input clips are from GoPro Hero Black in 2.7K format. Problem exists both for 4:3 as 16:9, 25 or 50 fps. I tried converting the files with handbrake/mpeg stream (maybe I did it wrong?)  with different codecs and into different formats, but the problem still exists. If I let HitFilm make a proxy of the clip, the transition stutter is gone but the whole video itself is now extremely choppy, whereas normally it plays smooth.

I have a MacBook Pro Retina 15 (2015 model) with 16 gb RAM, 2.2 GHz Intel Core i7 and 500 gb SSD. Graphics are Intel Iris Pro 1536 MB.

Help is much appreciated. I tried multiple software programs, but I feel HitFilm is perfect for my needs and I like the UI very much.

Thank you.


  • Triem23
    Triem23 Posts: 20,679 Ambassador

    Hitfilm is slower than many NLEs in basic media playback. Additionally when doing a transition, any NLE is reading two parts of the same file at the same time. If you've scaled footage down to 1080p that's overhead. 

    You can set your viewer to half or quarter. That's really about it. Proxies really aren't intended to transcode long shots. The Iris Pro isn't a particularly powerful GPU. 

    For transcodes, what settings are you using? 

    This video has pretty much all the information you need on how and why to transcode. 

  • CleverTagline
    CleverTagline Posts: 3,337 Ambassador

    I think this is the video that @Triem23 meant to include:

  • Triem23
    Triem23 Posts: 20,679 Ambassador

    @jsbarrett ok, writing on my phone, watching "Arrow," I forget things. ;-) Good catch, ty. 

  • FishyAl
    FishyAl Posts: 45

    @Triem23 - Iris Pro iGPU has the power to use hardware decoding for H.264 AVC and even H.265 HEVC including HEVC10 (10 bit color) which potentially solves the problem of poor H.264 edit performance due to CPU decoding workload and also offers high speed encoding and Intel offer the tools to make use of the powerful iGPU. Problem is, most NLE software doesn't make use of it.

    Magix (who own Sony Vegas software) have made use of it in Movie Edit Pro.

    How Magix Made 4K 360 Video Editing Swift and Easy | Intel® Software

    The Kaby Lake-U/Y GPU - Media Capabilities - Intel Launches 7th Generation Kaby Lake: 15W/28W with Iris, 35-91W Desktop and Mobile Xeon

    "Intel claims that Kaby Lake-U/Y can handle up to eight 4Kp30 AVC and HEVC decodes simultaneously. HEVC decode support is rated at 4Kp60 up to 120 Mbps." - plus HDR and Wide Color Gamut (Rec.2020) support.

    H.265 is here as a camera format on the GH5 and DJI due to smaller file sizes and better quality than H.264 at the same bitrate for 4K. H.265 software decoding is more demanding than H.264. Edius Pro has added H.265 editing using Intel Iris iGPU.

    If a discrete GPU card is needed for Hitfilm compositing, it is possible to have both GPUs active in Win10 with two monitors - for me, smooth 4k editing with a 4k or1080p preview comes before compositing.



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