Exported Videos much too large in High Sierra

Cannot do that right now, as I am busy working on a project with Sierra running from an external SSD.

Without screeshots:

Complete clean installation of High Sierra on a Mac Pro (late 2013)

Installation of FCP x and Compressor from the App Store.

Loading a project that contains 3 minutes of HD Footage shot with a GH4 in 1080/50p.

Clicking the export-button in the upper right corner of fcp x (It says "Bereitstellen" on the German System I am working on, probably "Export" in english".

Choose "Export File" and use the settings from this screenshot:

In the lower right corner of this window you get an estimate of how large the output file is expected to be.

What I get is much larger.
Looking at the files with MediaInfo shows this:

Not the bitrate I wanted ...

Same results if I use Compressor for the output.

Doing the same thing in Sierra will get me a file that is appx. 350 MB.

As I tried a lot, it is hard now to find out wich files were written by compressor and wich ones by FCPX.

Strange: Even the files I exported in 10.12 Sierra and which have the bitrate they are supposed to have show this info when I open them with MediaInfo.

Looking at the Infos in VLC gives this window – for both videos:

The problem is the bitrate, not the codec.

Hi Tom,

I did some more testing too - and have to admit that I must have gotten something wrong.

It is the same here: Output Filesize from FCPX is almost identical in both systems.

I can't really recall, which file made me think that export in 10.13 was different from 10.12 - however, if it happened I am not able to reproduce the error.

So the problem is only happening in Compressor: Here are some files I generated in both systems by "send to compressor":

Sorry to have caused you this inconvenience, Tom.

Take a look at this thread please:

Excessively large files with Compressor on High Sierra

Looks like Apple Engineers are already looking at this for a few days.

Maybe it would help to let them know that there are more people with this problem.

Yes - footage as well as project are 50 frames.

Pls. have a look in the Compressor-Forum too. Somebody else has the same problems and posted some additional Screenshots.

It also happens when I export the Project as a Film in ProRes and use that in Compressor.

I am currently doing a few tests with other formats (PAL, 720p, 4K)

When I tried with nothing but a generated white background, the resulting files had very low bitrates - 216 kb/s for a 4K Video. As soon as im am using footage that is moving, the bitrate of the output files is very much higher than what is said in the settings.

This happens in FCP X as well as Compressor.

As I am not having any trouble in Sierra, it is not worth testing there.

I did the tests in High Sierra. Since I can still do all my work starting from an external drive with sierra running, I will stop this now and hope that apple comes up with a solution - in the thread at the Compressor-Forum a user reported that he is in contact with Apple Support regarding this problem.

Thank you, Tom.

To avoid misunderstanding:
When I am exporting Videos to h.264 format from FCPX or Compressor under Sierra, the results are like I expect them to be in size and bitrate.

When I do exactly the same in High Sierra, the resulting files are much larger - bit rate and filesize are a lot bigger.

If this does not happen with your system(s), this shows that it is not a general problem. But there is at least one other person who is experiencing this (see Compressor-Forum).

This is very kind of you, Tom, but I don't see that it makes much sense.

If you are not experiencing these problems so far, I don't think you will if you try again with other footage.

HS gives me large files indepenently from what footage I am using - camera footage from Lumix GH4 or G70 or from generators. Maybe this is not happening on all machines – I am working on a late 2013 Mac Pro.

I generated the files from the screenshot with the default "Publish on Youtube, Up to 4K" settings. But have tried other settings too. Even manually changing the bitrate did not lead to noteworthy changes.