So, after some trouble opening the program, I eventually got to editing my footage.  Here's the only problem, whenever a medium to large effect comes into play, my frame rate takes a suicidal plunge down a cliff.  This happened as well with Hitfilm 2, and I thought that this issue had been solved for Macs, but now I am encountering it again.  The effect I noticed this on was the dragon's breath, and when it starts the video gets all choppy and laggy, any advice on what I should do?  Otherwise, a great product that is fun and easy to use.


  • edited April 2015

    Thats the nature of the beast (no pun intended). Complicated particle effects (which dragon breath is) or large 3d models and things like that require a lot of power to run in real time. I dont have the most powerful computer, so I do things like turning off effects or layers I dont need to run while I work. Or make temp renders of certain layers. There is a proxy feature which helps as well by making temporary renders. I also turn off motion blur while I work. It slows things down, especially with particle effects.

  • Yeah, what NullUnit said. From your other thread I see you have a MacBook Air, which is not really a powerful machine for video editing compared to something like a MacBook Pro or a gaming laptop/desktop system.

  • I have the same problem! I'm on a Windows computer with Nvidia GTX 980, I7-2600, 8 gb RAM and the software installed on a SSD drive. The Dragon's Breath makes the frame rate choppy for me as well, and if I try to scroll through the effect, it lags alot. I also had this problem with Hitfilm 2. Really hoping someone has a solution for this, cause it puts some big limitations on what kind of projects one can make =/

    Hope you find a solution! :D

  • Well, the dragon breath effect in itself is a quite heavy particle simulator, producing thousands of particles each settings. you can try to turn down the particles per seconds value of each of the particle systems inside it to get better frame rates during playback, or activate the "Preview" toggle in the General controls.

  • UbiUbi
    edited April 2015

    Wouldn't be cool to, maybe, completely render the clip in-RAM and keeping it cached until something changes? This would make HF editing butter smooth. Just add RAM (i upgraded my system to 32GB and hope being able to use them all). If i recall correctly, Premiere lets you choose to render clips, so you can watch the entire video more smooth. I tried to make proxy but really this doesn't seem a working solution. With or without proxy a multi layered clip is still choppy. Anyway, let's say that proxy works in one way or other, this should be nice to proxy-ize also transitions between clips (light bleeding transitions as example kill the frame rate on my i7 with Quadro K2100).

  • Triem23Triem23 Moderator


    When you see big fx houses pulling off massive real-time renders, it's much better hardware than we have. If you've seen American Football (rugby for folks who need pads), that real-time scrimmage line is a $250,000 bit of gear. That real-time first-down line is another $250,000 bit of gear. One frame of "Frozen" took 180 computer-hours to render. 

    @Ubi RAM render does have an advantage... When the computer is on. Next boot, you have to render again--hence the disc-based proxies. With Update#3 I know they removed space restrictions on the proxy folder. 

    Ubi, you're in an odd position with your Quadro... That sucker is optimized for higher-end software with custom rendering engines (Vegas, Avid, FCPX, Premiere), where Hitfilm is using standard OpenGL rendering to try to be compatible with as much hardware as possible. It does mean Hitfilm doesn't render as efficiently as Premiere's sexy Mercury Engine (Although on my aging NVidia 580GTXm I do get better preview rendering in Hitfilm than AE). 

    Still,the bottom line is that video editing is very-very resource-intensive--a 1920x1080 frame is six MEGABYTES of data per frame, per layer--with any video codec the computer is now rebuilding frames from compressed data: a 20Mbps mp4 is 2.5 megabytes per second. A 30fps 1080 stream is 180 megabytes per second. That's huge processor load to decompress! This is oversimplifying things, but now you add a particle system in there and you have thousands of physics calculations, and render calculations on top of the 180 megabytes per second the frames take up. 

    Feature films shot in 4K (or higher) are not cut in 4K. They are cut in 1080,or even 720, only going back to 4K after effects and color grades when everything is locked in time for final checks

    Sorry  if this is grumpy, but one thing I tell my students in my animation/compositing classes is that if they're not getting system slowdown, they're not pushing the system enough. 

  • UbiUbi
    edited April 2015

    @Triem23 well, i know that having a Quadro mounted on my laptop is not the best solution in every field of application. Anyway, if i concatenate several full hd videos in the HF edit timeline without any effect, i can scrub them in realtime back and forth (with prores shooted by BMPCC) from my SSD and it's butter smooth. When i apply a cpu intensive dissolvence or some complex composite shot the frame rate goes down. From this experience i can guess that if HF could keep a rendered clip in RAM (it's ok for me also to re-render it once for each working session, maybe persisting to disk would be better) i theoretically can keep the original smoothness. I don't pretend that my $2,500 ZBook 15 to work like a $250,000 dedicated solution, but it has enough horsepower to move a bunch of FHD clips i guess :)

  • Triem23Triem23 Moderator


    Hey, I totally agree that persistent RAM renders are useful, and a great potential addition. However, I do see why we got disc proxies first. 

    Using Foxhome above as an example, he's got 8GB of RAM. After OS overhead and Hitfilm requirements, he doesn't have a much left for preview. Realistically, 1-2 GB. Which is about 10-20 seconds, max. With your 32GB, you could allocate 16 GB for previews and get about 90 seconds of RAM preview and have plenty left over. Again, why FxHome did disc-based renders. 

  • Ok ok, i totally agree about disk caching. But i cannot manage to get them working. I don't know that's wrong on my side but if i choose to make a proxy (and wait some time), my composite shot is still choppy. Then i can deactivate proxy and get the very same performance. Looks like there's no proxy at all.

  • @Ubi, what are you proxying? The original media or the composite? The problem with proxies is that they are huge and thus your disk could become the bottle kneck, but I see you have a SSD, so other than running out of space, it should be plenty fast. Are you sure the proxy has completed? In the media bin there is an icon showing the progress.

  • Triem23Triem23 Moderator

    Well. A possible issue with caching is what drives your cache is on, what else is the drive doing, etc. In an ideal situation we would have separate drives for OS, programs, cache, library/stock, project source, project render; with the project drives being RAIDs. 

    Also,I think proxy renders are slower than output renders, since HFP3 isn't devoting all it's run-time to render, but doing it as a low-priority background process under editing.

    Also, just to restate, a persistent RAM render is a great idea, and you should totally wishlist it. It's not as useful to as many users as the disc-proxy since a lot of us are still running machines two-three-generations old. :-) 

  • __simon__: the only thing i can proxy currently is a composite shot. it would be nice to proxy also the original media when effects or dissovences are applied over it. I didn't notice the icon you mentioned, when i come home i'll check over it, thanks!

    Triem23: Well i know that caching an entire short film is not possible with only 32 GB ram, but it would be nice when i'm dealing with trailers or musical videos because in this case you may end using many effects and the entire video can fit the ram. It may be nice also on longer videos, when i want to focus my attention to a specific time range i don't need the entire film loaded in ram but only the portion i'm working on.

  • UbiUbi
    edited April 2015

    Got it! My proxy folder was skrewed. I placed it on a real path and now it produces proxies. Maybe it could be useful being warned about path issues?

    A comment on proxy generation. I notice that it takes very long time, also for relatively short clips with nothing than some grading on them. I think this is due to the lowest process priority given to the proxy generator... is there some way to maximize CPU load on that process when i tant it to?

    @__simon__: now i see that icon you told me about. Never noticed it, when i drop a media on the timeline i never go back on the media panel :)


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