Having trouble with 4K Export

skitchyskitchy Website User Posts: 43
edited August 2015 in HitFilm

I imported a 4K image sequence (approx 30 secs long at 24 fps). Then I tried to export.

Wow. Just, unbelievable.

Firstly, it seems the only way to get a 4K video file out of Hitfilm 3 PRO is as an uncompressed avi. I *REALLY* hope I'm missing something here.

So I dutifully try to get said uncompressed avi out of Hitfilm 3 PRO. I waited the 12 minutes it took to render out the 30 second clip, utilising a whopping 30% of my GPU processor (checked with MSI Afterburner).

This produced an avi with a size of around 10GB (understandable with no compression. Trouble is that NOTHING will play the file and NOTHING will import the file. The file is completely broken / corrupted in one way or another. And yes I did try multiple times.

On the bright side if I just render the first few seconds of the timeline I can get a working avi out. So if you are thinking of making some 4K Vines then I suppose Hitfilm is the program for you.

I7 Sandybridge, GTX 960, Win 7 x64, 16GB RAM


  • Triem23Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,303 Ambassador
    edited August 2015

    Adjust your h.264 output settings. Change Profile from "Main" to "High," and change Level from 4.0 to 5.1. This will allow you to export 4K at data rates up to 240mbps. 240 may be overkill. Try 100. That should be more than enough. Since 20 is the data rate for Blu-ray 1080p, 4k is four times the pixel data, even 80 should be fine. 

    Hope this helps. 

  • Triem23Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,303 Ambassador
    edited August 2015

    Incidentally, file sizes for uncompressed avi at 24fps breaks down as follows :

    3840x2160x24=199,065,600 bits/frame

    Times 24=4,777,574,400 bits/sec

    Divided by 1024=4,665,600 kbits/sec

    Divided by 1024=4557.25 mbits/sec

    Divided by 1024=4.45 gbits/sec. 

    No storage media on the planet can sustain that data rate! 

  • skitchyskitchy Website User Posts: 43

    Thanks for the h.264 advice. I didn't think h.264 supported 4K so I'll admit that part was my error.

    The problem with the large avi wasn't a data throughput issue - it is a corrupt file. VLC and Vegas report it as being corrupt without even trying to play it. Just to make sure I tried the same export on a completely different machine with an AMD card with different source material and still got a corrupt avi. The throughput explanation also wouldn't account for why I can export a shorter avi clip without issue.

    I'm trying an h264 export right now, but I'm still only getting about 40% GPU utilisation. 

  • NormanPCNNormanPCN Website User Posts: 3,950 Enthusiast
    edited August 2015

     40% GPU utilization during a file encode/export is supposed to mean exactly what?

    Encoding/compressing a video file is a very poor use of GPU. Some GPU encoders force the issue and they can be fast but they do give up video quality compared to other non GPU encoders.

    A couple of references is you want to get technical.



    To encode a file, two things need to happen. The application needs to assemble/create the video stream and that stream needs be analyzed and compressed into the destination video format.

    The first part, the image processing and effects are very applicable to GPU parallel processing. The later, file encoding, is not very applicable. See my first link.

    Hitfilm uses the Mainconcept AVC/H.264 encoder. This encoder is by no means one of the faster ones. It is quite slow. However it does generate a pretty good quality for a given bitrate. IMO, x264 is about the best, but mostly at low bitrates. See second link. At high bitrates most anything is pretty good, even hardware GPU encoders can do well. x264 is GPL which poses a problem for commercial applications like Hitfilm.

    IMO, the 40% you see during a file encode is actually a pretty good overall utilization given, the two processes and the AVC file encoder is not using the GPU.


  • Triem23Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,303 Ambassador

    Also, depending on how complex the project is a high amount of render time might be waiting for the drive to write data. On my system I get significantly faster render times with image sequences than mp4. Transcoding the image sequence to a video file is fast, but that two-step output usually takes less time than a straight mp4 render from Hitfilm. Obviously your mileage may vary, depending on project and hardware. 

  • Aladdin4dAladdin4d Moderator Website User, Imerge Beta Tester, HitFilm Beta Tester Posts: 2,509 Enthusiast

    So not sure why you end up with a corrupted AVI. You might try opening it in VirtualDub with the extended options dialog and see what happens.

    GPU utilization - NormanPCN covered it pretty well. The only thing I would add is even with a GPU accelerated encoder your GPU will spend most of the time waiting on data to encode. 

    @Triem23 - Today I went to a demonstration of a data storage rack. A single unit is a 32 drive array with a sustained transfer rate of 192 gbits/sec and the rack holds 32 units. 

    32 x 32 =1024 drives

    1024 x 8TB = 8.192 petabytes. 

    It's the size of a very large bookcase, takes 14 kilowatts to power it not to mention what it takes to cool it, costs more than my house and I'd need a forklift to get in my house and I just don't care about any of that because all I can think about is how much I want one.

  • skitchyskitchy Website User Posts: 43
    edited August 2015

    I may have found the problem. It seems that standard avi files could have an upper limit on their size due to their internal structure. Source :


    There is mention of an extended avi format called OpenDML on that page which overcomes this limit, so if any devs are reading this perhaps that would be something to look into. I think that being able to render to a lossless video format is important, so perhaps you could look into something along those lines. Apparently there is even an h264 lossless variation https://en.wikipedia.org/wiki/List_of_codecs#Lossless_compression_2

    If you want to try this glitch for yourselves :

    - Start a 4K Ultra HD 24fps project

    - Create a 30 second clip (use a new comp and just add the 'grid' effect if you don't have any source material - this will be fast to render too)

    - Export as an uncompressed avi at 4K resolution.

    Re the long render times, I'm hoping that the bottleneck is with reading the 4K image sequence, so I've ordered a new SSD to test the theory. Why do I think this? Because rendering something that is completely generated within Hitfilm (like a grid) is very quick. It might also be something to do with PNG decompression times.

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