GTS 450 problems with hitfilm slowing

Hi, I have a brand new pc with 4 gb of ram and 1 tb of memory, I also have a nvidia GTS450 graphics card but am having problems when scrolling frame by frame through my projects.
Is there anything I can do to speed this up please.

i3 processor
nvidia GTS450 video card
4gb ram
1TB memory


  • AxelWilkinson
    AxelWilkinson Posts: 5,255 Staff
    Make sure you have the latest version of Hitfilm installed, and then make sure that you GPU drivers are up to date:
  • I have installed the the latest driver for my graphics card yesterday and i think i have installed the 1.1 update for hitfilm (i'm not sure though but i am able to scale to fit which is a 1.1 feature so i am guessing so).
    I recently made an intro for our youtube channel purely from scratch and only using features from Hitfilm Standard itself and that runs incredibly smoothly. Yesterday however my friend got a new camera and we tested it out on his greenscreen. i imported this test video and made a new composition which lasted about 2 minutes 30 seconds and keyed out the greenscreen. I then wanted to add background videos to look like we were in different areas but when scrubbing (i think thats the right word) through the video, it keeps freezing. I want to be able to find the right place exactly so i can drop in the background but when clicking the next frame buttons it works reasonably fast but when clicking the previous frame button, it takes about 10 seconds to go to the previous frame and not allowing me to do anything in that time.
    Also sorry to be a pain but this reminded me of another little question about keying. I first use the colour difference key and mess around with the min and max to get the best result (which tends to be min 0.94 and max 0.96). I then want to get rid of the green spill but when adding spill removal it automatically brings back my greenscreen background but in a blue grey tint and when i take the strength all the way down to 0 it is exactly the same as if it wasn't there and just gets worse the higher the strength is.
    Sorry for so many question, i enjoy making films but am reasonably new to special effects and new to Hitfilm.
  • AxelWilkinson
    AxelWilkinson Posts: 5,255 Staff
    Performance being slow when moving the playhead backwards is likely a codec thing. Most video cameras use codecs to record video that are not designed for editing, they are designed to keep file sizes as small as possible, and basically the way they do this is to find areas of the frame that are similar throughout a period of time, and compress that area of all the frames it appears in together. So instead of each frame being compressed individually, you get temporal compression, where before any single frame can be displayed, perhaps 30 frames have to be decompressed. Because they are all mashed together to save space. The exact number varies, but hopefully you get the concept. These codecs optimize the process for playback, but when trying to go in reverse, the load on the processor can be much greater.
    So, my recommendation would be to try converting your footage to a proper intermediate codec designed for editing and see if performance improves. Personally, I use Quicktime Animation, or ProRes (but you need Final Cut for that option). Files will be larger, but performance will improve, and quality retention will increase significantly.
    As far as the greenscreen issue, if you can attach an image demonstrating the problem, it will be easier for us to offer specific suggestions. Spill suppression won't bring back any background you have removed, so if you are noticing it more after the Suppression, then its likely just the color shift making it more obvious. Perhaps adjusting your key differently would help, or possibly adding a second key, if the color range of your greenscreen is too large for a single key to handle effectively. But again, I can't say for sure how best to handle your particular situation without seeing something for reference.
  • Stev1e4
    Stev1e4 Posts: 30
    I used a software called FormatFactory that i downloaded to change my video recorded on the camera to a quicktime movie file and it runs a lot more smoothly in HitFilm but a new problem has arised, for some reason now i can not key out the greenscreen, the colour difference effect isnt having any affect on the video :S
    I have attached an image on the problem with the spill removal effect giving a blue tint and have just realised that with big movement like at my arms, the video has got lots of lines if you can see in the picture, could you please explain why this is happening.
    Again sorry for all the questions (i think i asked 3 this time :0) very sorry
    Thanks Stevie
  • AxelWilkinson
    AxelWilkinson Posts: 5,255 Staff
    That picture looks like you have the Spill Removal tool being applied before the key, which will indeed stop the key working, since the Spill Removal will remove all green from the image before the key is applied. Make sure the Spill Removal comes after the key in the list of effects applied to the layer.
    As far as the lines around the fast-moving areas of the frame, that's interlacing created by your camera.If you are working with interlaced footage, you need to make sure to handle it properly when running the footage through any sort of conversion. Its not gonna show up when the footage is viewed on a television, and if your footage is meant for computer or online viewing, you will need to de-interlace it at some point. Usually this is done during the final render of the film, so maximum quality can be retained as long as possible.
  • Stev1e4
    Stev1e4 Posts: 30
    ok thankyou for your fast reply. The spill removal is working now (silly mistake i made to be honest) and keying is looking a lot better.
    Quicktime movie files are working a lot faster now which makes me happy as i am not patient at all.
    One last question to clarify, the lines are annoying when keying but if they disappear after rendering then how can i see what my key would look like when rendered before i have actually finished and rendered the whole project?
    Thanks :D
  • AxelWilkinson
    AxelWilkinson Posts: 5,255 Staff
    Ideally, use a progressive-scan camera, rather than interlaced. Most modern cameras can record progressive-scan footage, and Hitfilm is designed to be a progressive-scan video application. It doesn't have tools designed to work with the less-and-less common interlaced video formats. So when using interlaced footage, make sure that you have the correct project settings selected. They should match the formatting of your footage exactly.
    So, another option is to de-interlace the footage early on, before importing into Hitfilm. But you are literally throwing out half the video data when you de-interlace, so this isn't always the best choice. There are tools available to retain the information when de-interlacing, like Magic Bullet, but they aren't free.
    Another option is to render out a small portion and watch it back on a television, perhaps by putting it on a DVD. this will at least let you know whether your particular footage is going to look OK after being processed in HitFilm, or whether some de-interlacing early on is going to be necessary in your case.