Proxy File Sizes

I have two different project. Both shot with my GoPro Hero 11. The settings are all the same other than the frame rate (see below). When I create proxy media for each project's videos, I get (to me) unexpected results. The proxies created from the 30FPS videos are about 8 times larger than the proxies from the 60FPS. and are eating a ton of disc space, despite the source files being the same length and size.

I clearly don't understand how proxy generation works, because I expceted the 30FPS source files to create smaller proxy files than the 60FPS.

Am I doing something wrong?

In both projects, I have:
Proxy media resolution: Choose automatically
Proxy media format: DNxHR HQX

Project 1:
60FPS
Source files are 12:48 long
Source files are 11.2 GB in size
Bitrate: 120 Mb/s

Project 2:
30FPS
Source files are 12:48 long
Source files are 11.2 MB in size
Bitrate: 120 Mb/s

Project 1 Proxy Media:
File size: 10.4 GB
Bitrate: 112 Mb/s

Project 2 Proxy Media:
File size: 82 GB
Bitrate: 875 Mb/s

File size = Bitrate x Duration.

Specs like resolution, frame rate, etc. really have no impact on file size.

That 875 bitrate is your culprit.

File size = Bitrate x Duration.

Specs like resolution, frame rate, etc. really have no impact on file size.

That 875 bitrate is your culprit.

That 875 bitrate is the proxy file, not the source. Both sources are the same length and bitrate. That being said, I just tried re-generating proxy files for the 30FPS project and they came up much smaller. About half the size of the 60FPS project. So that problem appears solved, no idea why though.

But here's another weird issue. Sometimes when I generate my proxies, the audio randomly cuts after a few minutes. The waveform on the audio track goes blank partway through and there's no sound from that point onward in the clip. If I switch back to the camera original, the audio returns. I even tried playing the proxy file in a different media player and the audio cuts at the same spot.

If I delete and regenerate the proxies, eventually I'm able to generate them with full audio.

DNxHR proxies are supposed to be massive. 6gbyte/min for 4k.

H.264/265 are very compressed and intensive to decode in real time. Giving you stuttering in Resolve.

By decompressing them to Dnxhr proxies you will make the project must smoother to edit.


I personally use 1/4 resolution DNxHR LB proxies for editing on the timeline and then disable proxies to go back to the full quality originals for color grade and final export. Color work is never going to have real time playback anyway, so DNxHR won't save you anything.

DNxHR proxies are supposed to be massive. 6gbyte/min for 4k.

H.264/265 are very compressed and intensive to decode in real time. Giving you stuttering in Resolve.

By decompressing them to Dnxhr proxies you will make the project must smoother to edit.


I personally use 1/4 resolution DNxHR LB proxies for editing on the timeline and then disable proxies to go back to the full quality originals for color grade and final export. Color work is never going to have real time playback anyway, so DNxHR won't save you anything.

I totally get that proxies can (and should) be larger than the originals. What I don't understand is the inconsistency. If twoh files are the same length and bitrate, shouldn't the proxies be roughly the same size (assuming the same proxy output settings)?

I also re-generated proxies off the original 30FPS video and they ended up being slightly smaller than my originals this time around. Not sure why.

If they are meant to use up lots of disk, I can live with that in exchange for a smoother editing experience. But I don't understand why it doesn't always behave the same.

That 875 bitrate is the proxy file, not the source..

I know. Using such a high bitrate to create the proxy is why you got such a large proxy file.

That 875 bitrate is the proxy file, not the source..

I know. Using such a high bitrate to create the proxy is why you got such a large proxy file.

Ah ok - but why would a source file at 30FPS using the same bitrate produce much smaller proxy files?

That 875 bitrate is the proxy file, not the source..

I know. Using such a high bitrate to create the proxy is why you got such a large proxy file.

Ah ok - but why would a source file at 30FPS using the same bitrate produce much smaller proxy files?

DNxHR data rate is actually frame data x frame count = data rate per second.
Since you have half the frame rate (60 vs 30), the same quality setting should result in half the file size assuming everything else is the same.