Video Problem?

[Joe Marler]

[Jim Hart] ” The jittery is only happens after being uploaded to Vimeo and YouTube. Even then, it plays perfect in Safari. It is the other browsers that are jittery.

So, to to be clear,…you want me to try and export as 1080P 60FPS, upload that to Vimeo, then download the file from Vimeo and play it on my Mac?”

First export as 1080p/60, upload to Youtube and Vimeo, and try normal streaming playback with Mac Chrome & Firefox. If shooting at 1080p/60 with your camera avoids the problem, maybe just exporting from FCPX at 1080p/60 then uploading that file will avoid it.

Re downloading the file, after upload the file is re-encoded by both Youtube and Vimeo. You are not streaming the exact file you uploaded. It seems likely there is something going wrong with the Mac version of Chrome and Firefox when streaming an uploaded 4k file — even if streamed at 1080p. However — maybe the cloud-based re-encoding process did something which exposes a bug unique to Mac Chrome and Firefox. Downloading that re-encoded file lets us investigate that locally.

With Vimeo (not Youtube) it’s possible to download that re-encoded file. If your Vimeo account has enabled downloads, you’ll see that option. However this is only available for Vimeo Plus, Pro, Business, and Premium versions.

If you have one of these versions you can download the re-encoded file and try to play it with Quicktime, VLC *and* Chrome/Firefox. To play a local file with a web browser, enter the path to the file. An easy way to get the complete path is drag/drop the file from Finder to Terminal. That will produce the complete path and you can copy/paste that file pathname from Terminal to the query box in Chrome/Firefox. It will locally decode and play the file in the browser.

If you don’t have the right version of Vimeo you could try to capture the stream using one of the available 3rd-party tools, then try to play that file. The capture tool I use is Downie, but there are many: https://software.charliemonroe.net/downie/

This could be a bug in the Mac version of Chrome and Firefox, or it could be an underlying MacOS bug which Chrome/FF are exposing.

Even if isolated to 4k/60, it is a troubling situation because you tried both ProRes and H264, and 4k/60 uploads are very common, as is playback by Mac Chrome and Firefox.

There have been so many serious bugs on Mac Chrome that I personally would not advise any FCPX user to use that, but even excepting that, the jitter problem also happens with Mac FireFox.

[Jim Hart]

I exported as 1080P 60fps (doesn’t look as good) and I uploaded it to Vimeo. Once it finished processing, I downloaded the encoded 1080p file and played it on my Mac…played perfectly. Uploaded it to both YouTube and Vimeo…played jittery.Safari, still good.

I am at a loss…I just don’t get it.

[Jim Hart]

Should I take the original Final Cut Pro export and save it to an external drive, and then connect to a PC and upload to Vimeo? That may work if there is a bug on the Mac versions? I am going to try that tonight.

[Joe Marler]

OK, I will work on this more tomorrow. I am concerned there’s a generic problem with the stream decoder on Mac Chrome and Firefox for certain scenarios, maybe unique to certain Mac hardware types such as those with a certain version of Quick Sync on a certain MacOS version. It is subtle enough that most people wouldn’t notice it but if you care about quality to a diverse viewership, it’s not good.

[Jim Hart]

I exported the file as normal to an external drive. Attach the drive to a Windows 10 PC and uploaded the video to Vimeo through Chrome. Same issue.

I don’t know what I am going to do.

[Jim Hart]

I think certain Mac hardware might be my issue.PC’s play fine. My MacBook Pro and MacBook Air play all browsers fine as well I just discovered…it is my 2017 iMac and my 2020 iMac Pro that play jittery in all browsers but Safari. WTH?

[Joe Marler]

[Jim Hart] “I think certain Mac hardware might be my issue.PC’s play fine. My MacBook Pro and MacBook Air play all browsers fine as well I just discovered…it is my 2017 iMac and my 2020 iMac Pro that play jittery in all browsers but Safari. WTH?”

This is a complex issue. I don’t think FCPX is doing anything wrong. There is a performance deficiency in the video decoding in Mac FireFox and Chrome. FireFox is worse, and it happens during local disk playback by the browser, not just during streaming. IOW you will see it in FireFox by just doing File>Open and playing the clip – before uploading it. However it must be 1080p as FF apparently can’t play a local 4k H264 clip with good performance.

It’s not hardware specific as I tested a 2017 10-core Vega 64 iMac Pro, a top-spec 2017 iMac 27 and a top-spec 2019 MacBook Pro 16, and it happens on all of them, all running Catalina 10.15.5.

I then tried exporting the same 4k/60 file using Resolve Studio 16.2.3, and it seemed to not happen. Inspection of the file header shows Resolve used a keyframe interval of 120 frames, whereas FCPX used 30 frames.

I then sent the same timeline to Compressor and created a custom preset for a keyframe interval of 120, and it seems to work better (maybe not perfectly) in FireFox, including after upload and transcode by Youtube.

FCPX is not doing anything wrong, but this might be a workaround. The larger keyframe interval may be making the decode easier. If you have Compressor you can create a similar preset and use that. In Compressor under Video Sharing Services, right-click 4k and pick “duplicate”. That creates a duplicate preset you then modify.

Select that new preset in the left sidebar and at the right, select the video tab, for Data rate pick “computer playback”, for Key Frame Interval pick “Every” and enter 120 frames.

Then in FCPX do File>Send to Compressor and in Compressor drag/drop your new preset on top of the project in the middle pane, then click the Start Batch button at the bottom. When it finishes upload it to Youtube and test the playback in FireFox.

[Jim Hart]

Joe,

Thanks for the help. I opened compressor and followed your directions and added the duplicate with changes to my final cut pro sharing window. I shared my raw timeline using the newly created compressor setting and uploaded the resulting file.

Plays fine in Safari, play almost perfect n Chrome, Firefox is still bad.

[Joe Marler]

[Jim Hart] “Plays fine in Safari, play almost perfect n Chrome, Firefox is still bad.”

I just tried a 4k/60 ProRes file from a BlackMagic camera, exported from Resolve Studio 16.2.3 to 4k/60 H264, keyframe size=30, uploaded to Youtube and the jitter still happens if streamed from Mac FireFox 77.0.1 on an iMac Pro running Catalina 10.15.5.

This proves it has nothing to do with FCPX. It is a problem with Mac FireFox and (to a lesser degree) Mac Chrome. Whether the fault is in the app itself or how the app is using MacOS APIs or MacOS itself is unknown.

Obviously this is a major issue for any streaming content producer who wants consistent high quality presentations across various platforms. The entire goal of browser standardization is to avoid directives to use one type of browser or platform.

At this point there are three steps to take: (1) Try to find a workaround, (2) Further examine problem bounds on various platforms, e.g, does it happen on Chrome/FireFox on iPad? Does it happen on MacOS before Catalina? (3) Report the bug to Apple OS support (not FCPX), Google and FireFox.

I haven’t looked so far, but it can probably be seen on various Youtube material people have uploaded, if played by Mac FireFox. There is nothing unique or incorrect about what FCPX or Resolve are doing on the encode side.

[Jim Hart]

Thanks. Since I know it is not my video, which is what was worrying me, then I am going to forge ahead. Thanks so much for your help…incredible effort on your part and I truly appreciate it.

What is odd is that all browsers, firebox included, play fine on my 15 inch MacBook Pro and my MacBook Air.