A short while ago I fell foul of the following on YT:
The maximum file size you can upload is 128GB or 12 hours, whichever is less. We’ve changed the limits on uploads in the past, so you may see older videos that are longer than 12 hours.
However, I have noticed that some channels are able to create over 8 hours of 4K videos. Are those videos actually 4K, or is there a way of getting around those restrictions mentioned above?