Not really effective while exporting movies.

AndreasFrankeSLAndreasFrankeSL Website User Posts: 3

If I look right, HitFilm4 Express isn't really effective if it come to export a movie. Could it really be, that the exporter is still using just one core?

Look at my screenshot:!AjgGhHvp8bcPisdWGvJL5irSNe0aEw



  • kevin_nkevin_n Website User Posts: 1,926 Enthusiast
    edited August 2016

    It's doing that because your GPU is too slow. The CPU is asleep from boredom. :P

    Happy CPU: 

     This screenshot is not mine, but in order for it to say 100%, it would require a way faster GPU than shown in the image, dunno what he used.

    I understand why this is confusing to you, that's because the vast majority of NLE's use software on the CPU when rendering (Adobe, Sony, DaVinci and so on). HitFilm on the other hand use OpenGL on the GPU, this is a more efficient and faster way to do it, provided the rest of the system is properly balanced, be it RAM, GPU, DISK or CPU.

    The GPU is the biggest bottleneck to HitFilm performance.

    Something doesn't make sense with my explanation though, I would love a long and detailed explanation on how the H.264 encoder works. :)

    Here's a response from one of the developers for HitFilm:

    The exporting works like this:  Render frame on GPU; encode it on CPU; render next frame on GPU; encode it on CPU.  And so on.  At periodic intervals a bunch of encoded frames will also be written into the file container on disk.  The encoding threads have to wait on the next frame to be rendered by the GPU before they can actually encode it.


  • TheOligopolistTheOligopolist Website User Posts: 3
    edited September 2016

    I am also getting very slow rendering times, at the moment it's taking about 3 hours to render a 14 minute video. I've noticed GPU usage is almost zero:

    This is a Desktop so there's no other GPU to confuse things.

    Does anyone know what might cause this?

  • kevin_nkevin_n Website User Posts: 1,926 Enthusiast

    Another example of less than 4 GB RAM used. This is so strange, the developers say that everything is alright. When I export a simple project, my GPU is using about 1 GB of VRAM, I have 4 GB in total.

    Do you want to try the same project just some random effects and compare our results?

    CPU: AMD A8-5500
    RAM: 4 GB
    GPU: R9 380
    HDD: 1 TB 7200 RPM

  • TheOligopolistTheOligopolist Website User Posts: 3
    edited September 2016

    The project I'm rendering there has a few compositions, and graphics overlays. I also tried to re-render a video of a different format, no editing or effects and it was also painfully slow.

    Edit: So I've read several times that re-encoding with handbrake with a constant frame rate will improve performance depending on how a video is encoded. I'm fairly certain the source clips I'm using are already a constant 60FPS h.264 but just to be thorough, I re-rendered a 30 second clip using the recommended settings in handbrake. I opened a new 720P 60FPS project in HitFilm, dragged my newly created 1920 * 1080 60FPS CF clip into the timeline, fitted the picture to the frame and went straight to export. I got an estimated time to completion of 30 minutes. Something odd going on.

    PC specs are:

    i7-3820 @ 4.2Ghz

    Nvidia GTX670 - Running latest drivers

    16GB DDR3 1600Mhz

     Edit 2:

    Well, I've tried doing some more stuff with hitfilm today and now I'm getting expected GPU usage and everything is moving along much faster. I'm not sure what broke it but it's working fine now.

  • AndreasFrankeSLAndreasFrankeSL Website User Posts: 3
    edited September 2016

    Ok, I see my GPU is to slow. But in other video software I could switch to "CPU mode" in this case and the software will render much faster. Because I'm working on a laptop, I can't change the GPU. 

    This is a example, that shows the different rendertimes in Video Deluxe:

    Movie lenght: 7 Minutes

    Rendertime GPU:  >1 hour
    Rendertime CPU:  3 minutes!!!

    So it would be very nice to switch the rendering mode. 

  • kevin_nkevin_n Website User Posts: 1,926 Enthusiast
    edited September 2016

    Laptops are known to be bad value and never balanced in terms of GPU power. Theyre packing i7s with weak GPUs all the time, which is ridiculous...

    HitFilm does use the CPU when rendering, but GPU does the most work. If your GPU is too slow, then your CPU have to wait for the GPU.

    HitFilm is using OpenGL on the GPU to render, other software dont use the GPU at all, apart from a few effects that can be GPU accelerated.

    Technically youre not switching from GPU to CPU in other software, because theyre rendering using software on the CPU in the first place.


  • TheOligopolistTheOligopolist Website User Posts: 3

    I believe I figured out what the issue was on my end.

    I had a process for a game that hadn't closed properly running in the background. Even though it wasn't using any resources it seemed that Hitfilm didn't want to use the GPU with it running in the background causing very poor performance. Making sure you don't have any processes running that might be using the GPU may be necessary to get Hitfilm to perform at an acceptable level.

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