[SOLVED] 50fps footage in 25fps project is only 12.5fps after stretching to 50% speed

edited August 2017 in Express Support

I am using the latest version of Hitfilm Express 2017 (5.0.6718.7202) on Windows 10 and have a problem with using high fps footage. When I create a normal 1080p 25fps Project, import a 50fps Video (recognized as 50fps in Hitfilm too) and put it on the timeline, it plays back at 100% speed (so it shows every second footage-frame for one project-frame) as expected. But when I set the speed to 50%, I would normally expect it to be fluent 50% slow motion. Instead the player shows only every 2nd of the (originally) 50 frames per second (every second footage-frame for two project-frames), so I have, instead of the expected 25 frames per second (or 50 frames per 2 seconds) only 25 frames in 2 seconds.

However, if i use an 50 fps interlaced Video (correctly recognized as 25fps), add the deinterlacing effect and set it to alternate, it gets "converted" to 50 fps and works fine, so when i stretch it, it shows all frames and gives a fluent slow mo.

These effects are kept on export too, and I know my Video is true 50fps because VLC shows all the frames. -> It seems like a bug in Hitfilm.

Thanks for your help/fix/efficient workaround!


  • edited August 2017

    You need to set the properties of the clip to 25fps in the Media Bin. i.e. you are saying to Hitfilm: "Ignore what the header says, this is 25fps video"

    Then it will use all the frames when you put it on a 25fps timeline and run at half original recorded speed.

    If you want it to then run at 'normal' speed, either have another version in the Media Bin that you haven't adjusted, or Right Click and set the Speed/Duration to 200% when on the timeline. It will drop every second frame.

    If you want it to blend the frame pairs instead, then use the Speed Effect, set to 2.0.

  • edited August 2017

    That is the way Hitfilm operates. Other editors too when it comes to literal "effects" like Speed.

    The media is conformed to the timeline framerate and then effects and such operate on that. After conformance the original frames and frame rate have been altered. I'm not 100% sure but I think the rate stretch tool operates the same. Rate stretch is not an effect like Speed so it can operate differently but I think it still operates the same in HF. I should probably do some tests.

    To keep all the frames of the 50fps footage you need to have a copy of the media in the Hitfilm media panel and set the framerate of that to your desired rate. Remember you can import the same media more than once. Or just duplicate in the HF media panel. You can pick a rate of 25fps for example which is 1/2 playback speed (50%). Now then when you place that media onto a 25fps timeline there is no conformance necessary. If your desired speed is 67% for example then just speed up the clip using rate stretch or Speed. In speeding up HF is throwing away some frames but it still sees all frames recorded by the camera.

    One thing to remember is that altering the playback rate in the media panel only affects the video speed. It does not change audio. This is just like the Speed effect. Rate stretch will affect the audio but you get the comical sounding pitch altered result.


  • edited August 2017

    I am having the exact same issue. Following NormanPCN suggestions of copying the media and changing the frame rate to 1/2 seems to work when importing into the timeline. The next issue is that after doing so, I can only trim/use half of my media. Once the trimmer gets to the midpoint, it just says "Could not play frame" for the remainder of the video.

    To McLP point, it does seem like a bug in Express. Hitfilm Pro instructional video found here, doesn't seem to have our same issue.

  • @mjstein32 read our posts again. You change the properties in the media bin, not after it's on the timeline. :)

  •  I did change in the media bin. Then when using the trimmer prior to adding to the timeline, I am unable to use the second half of my media. The trimmer displays "Could not play frame"



  • @mjstein32 strange as it's working fine for me. Just tried it in both Express and Pro 2017 with an 11;30 second 59.94 fps clip dragged into a 29.97 fps project.

    RMB>Properties in Media Bin, deselect 'From File' check box and select 29.97 from Frame rate dropdown.

    Drag onto timeline and it's now 23;00 seconds long and I can trim it in the Trimmer, first half (with audio), second half (with none) or straddling the middle (half audio, half silence) , or slice it on the timeline.

    Only slight weird thing is the Trimmer still shows it as being 11;30 long on the slider, whereas I would have expected that to change to 23;00.

    Do you have the latest 2017 update from about a week ago?

  • @Palacono That is a great idea to apply the update! I will have to give that a shot tonight. I also did notice the audio does play at original speed. One way I was able to work around the "Could not play frame" issue was to set desired In/Out on the 60fps clip, then duplicate in the Media Bin, set the copy to 30fps, and drag to timeline. This gave me the buttery smooth slow-mo on media in the seconded half of my video clip. I will comment tonight if the update helps the "Could not play frame" issue. Thanks for your help!

  • Thank you all for your help! Shortly after I posted this, I found Palaconos workaround by myself, but thought it was impractical if I needed just a short portion of the video, but thanks to the idea of NormanPCN to create a copy inside hitfilm if needed, I can now work fluently with my 50fps video!

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