4K video becomes way to large file size?

I’ve done some recording with my Dji pocket 2 in 4k and the raw file size is around 8gb. When I put the file into Shotcut and export using “youtube” preset with 3840x2160 pixels + 85% quality, the file grows to over 20gb.

Anyone know what settings I need to use to get my file to be the same quality as my raw file with the same size? I did something like 75% quality and the outcome was way worse then my raw files quality and the file was bigger.

Maybe there is some other setting I need to use?

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You don’t need 85% quality, nor 75%. You normally won’t see any quality loss down to 60…65%.
What video mode do you use?
Do you use a lot of filters like sharpening, color settings etc.?
This could increase file size quite a lot. What format/codec is your raw material?

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Video mode was set for HD 1080p 60fps in Shotcut(settings > videomode). Think I changed this when I wanted to try to make the file smaller 4k > 1080p for a test.

No, no filters at all.

Format/codec, how do you check this? I recorded in 3840/2160 60fps on my Dji pocket 2. The file was an mp4 on my sd card.

I’m very new to this so I hope you have patience with me. :grinning:

Can you post a screenshot of the “Video” tab on the properties panel for one of your Dji pocket 2 files? That will tell us the video format of the source clip.

This is normal behavior. When you edit video, it must be re-encoded, and most compression loses some quality due to the nature of how they work to compress. Every time you recompress you lose some quality. But if you compress too little to retain more quality it will create a bigger file. There are some other tools that can cut video without recompression, but they have many limitations and caveats.


Honestly i dont see much of a quality loss if i re-encode in 75% quality. But it all depends on the quality of the original material and the codec and settings it was recorded in. Also 4K with 60 fps will get you already quite huge files normally, if the size was rather small it must have been compressed a lot which leads to quality loss. How long is the orig. video?

Here it is.
video settings

My video is around 10min long. My dji cuts of the video into files of around 4gb per video.

I’m looking for the properties panel in Shotcut. It looks like this:

I looked up the specs for your camera, and I found this:

  • 3840 x 2160p at 24/25/30/48/50/60 fps (100 Mb/s MP4 via H.264/AVC, MPEG-4)
  • 2720 x 1530p at 24/25/30/48/50/60 fps (100 Mb/s H.264/AVC, MPEG-4)
  • 1920 x 1080p at 24/25/30/48/60 fps (100 Mb/s MP4 via H.264/AVC, MPEG-4)

Since you are targeting the same size file, you could try to use average bitrate instead of quality based. That will result in a more predictable size. Here is an example - be sure to use two-pass for best quality:

Thanks again, here is the video settings.

When you say “two-pass”, you mean “dual pass” right?

I changed to average bitrate now but under “bitrate” there is only max 80M b/s. On your image you had 100M. GOP, B frames, codec threads etc I will change to your settings and try.


I had to manually type in the 100M since that is not a default option.

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I exported a video with your settings and it worked out great! Weird thing is the video quality looks better than my other exports and the file is now only a little bit over 4gb. While the raw file is a little bit over 5gb. How does that work out?

Do you think I need to tweak anything else to make it at least the raw file size? Or maybe changing 80M to 100M will do the trick?

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The math checks out. It sounds like 100M would meet your needs. However, with a dual pass encode, I would expect the Shotcut export to be able to match the original quality with a much smaller size. I suspect that if you were to do an export at 60M, you would not be able to tell the difference in the quality.


Thanks again, you have been very helpful!

FWIW, I now upload video to YouTube using “lossless H264”. On the codec tab change GOP to 30 (i.e. 1/2 frame rate) and BFrames to 2 as per the YouTube recommendations.


I don’t see the point of getting Shotcut/ffmpeg to munge your video when YouTube is going to re-encode anyway. File size should be roughly the same as source files provided not a bunch of filters on the input video.

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