For the record, I develop using shotcut on Fedora with 32GB ram and a 6GB gpu.
My question is in regards to the quality setting when rendering a 4k video. When I render a final version of a video for YouTube my goal is to render the highest quality possible so that any downsampling youtube does it will be starting with the highest quality.
The default quality setting for YouTube is 55% but I have heard people suggest 67% may be the highest quality setting visually perceivable and beyond that you can’t visually see a difference. So my strategy has been to use 67% quality with alac audio when renedering a 4k music video for youtube.
The issue I see is that when I play the rendered file directly in Gnome Videos player, it plays fine. However, when I play the same file in VLC player it starts out ok and then quickly freezes up, although it will play if I render it at 55% quality. My assumption is that VLC cannot handle all the additional data the 65% quality adds.
So, what should my takeaway from this observation be? On one hand, I feel I want to make sure my video will render and play correctly on VLC player so I question whether I should lower the quality back down to 55% but on the other hand, since this file will be uploaded to youtube and resampled anyway should I not worry about this and just trust that Youtube will render the video to correctly play for whatever device/bandwidth/player is streaming it?
In a slightly more general way of asking the same question which is really the heart of the matter: If my finished render plays correctly on one video player, like gnome videos for example, should that be enough to confirm that this is a good render to upload to youtube? Or do I need to manually test the render on different video players to make sure it plays on more than one especially since VLC is such a common video player?
If it plays better in one player it should be ok for youtube. You could also upload it to youtube as a private video and test the result yourself before switching it to public.
VLC probably needs some config tweaks in its settings to use more efficient GPU rendering, I had the same issue in VLC on my old PC where it could not play any 4K video from my Gopro smoothly but the same exact video file would play perfectly on my laptop which had a weaker CPU but way newer architecture so it could decode it at hardware level.
That would be sufficient, and that video player could even be the Source preview within Shotcut itself.
Your encoding settings look great. VLC sounds like it has a config problem. Have you tried mpv or any of its wrappers like Celluloid? I haven’t used VLC in forever because of its problems.
Another test (at the expense of a larger file) is to set B-frames to zero and see if VLC can handle playback at 67% quality.
YouTube can handle almost anything - it has to since users could be uploading video produced by anything from a cheap old cell phone to a casual user who randomly chooses their software’s output settings to a professional video workflow. So if you can find even one player that can play your content, it’s almost certain YouTube can deal with it.
I always upload my videos as unlisted and then do a test viewing of my own before releasing them. I’ve never had a problem, but this way I know for sure my video is okay.
As for the part of your question about what quality level to choose, I can’t give you a definitive answer other than to agree that YouTube’s gonna do what YouTube’s gonna do, and you have no control over that, so if you’re happy with the way your export file plays back on your computer, there’s probably nothing to be gained from cranking the quality level even higher.
Thank you for the great advice everyone. I think the one thing I still am unclear about is whether it is possible to upload a 4k video to youtube that plays great when I stream it, but is of too high ‘quality’ setting and so will possibly freeze up on some arbitrary other users who try to stream it on different devices/players and I may not ever be aware of that? Is that a thing that could happen? Or is the conventional understanding that youtube would prevent that from happening because it would know to resample the video properly for whichever device/player was streaming it?
Indeed. Once you upload your video, YouTube creates multiple versions of it so that it will have an appropriate version for whatever resolution and codec support a viewer may have. If you’re interested in more details, check out this article and the link in it that describes the custom hardware YouTube employs for this task.