Faster preview/prerender in Editor

Playback in Editor is sluggish and stuttering even after creating proxies. Impossible to edit and preview clips in realtime with 1080p res.
A Composite shot seems to cache the video temporarily (indicated by blue bar) but it does the job a LOT better than the proxy function in Editor.
Is there a similar functionality in Editor like that in Composite or prerender like AE for faster playback? Proxy helps a little bit only but not for realtime playback.


  • SimonKJonesSimonKJones Moderator

    Hey chibi, could you remind me what kind of system specs you have? The proxy system provides realtime playback for me, but it will depend on your hardware (as always!).

  • I7 3770
    8gb ram
    Nvidia 750 gtx ti 2gb
    Win 7 64bit

    I can playback 1080p clips in vegas in realtime no problem. Playback with ae after prerender is smooth but not before prerender as always.
    Hitfilm Editor even with proxy still stuttering. But if you convert to comp then "preview/prerender" playback becomes smooth and realtime.

    Thanks Simon.

  • Btw I'm using png image sequence in 1080p.

  • SimonKJonesSimonKJones Moderator

    The temporary preview in comps renders directly into RAM, which is why it's always super-fast - and also temporary. The proxy system creates files on disk, which are designed to retain maximum quality while still aiming for real-time playback.

    One of our devs revealed a few details about the proxy system a couple of weeks back:

    The proxy video codec was custom-built for HitFilm and is lossless, so you don't need to worry about generation loss with your exports. The codec was designed to achieve the best lossless compression it can while still allowing real-time playback. So it generally favours real-time decoding performance over compressed size. It handles both 8-bit per channel (32-bit RGBA) and 16-bit per channel float video.

    I would definitely expect real-time playback of proxy files on a system like yours. What kind of drive are you using for storing proxies?

    Also, are you working in 8-bit or 16-bit mode? (as set in the Project window)

  • Ok I didn't know the proxy is "aiming for real-time playback". I thought the proxy would enable normal playback like watching clips in movieplayers.
    When I shrink the screen for the Editor to 25% it seems to cope better with the 1080 pngs. But the Comp "preview" is really realtime. Wish we had that feature in the Editor since there's lots of ram to spare. In ae the prerender does the same and it works well to use up all the free ram space to "cache" the clip temporarily.

    Also I'm thinking the proxy is just not suited for 1080p image sequences. I'll try to shoot some 1080p videos and see how HF performs with video clips.
    I'm working on 8bit mode. Hdd is typical 2tb 7200rpm.

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