I use mp4 in 720p that works great, but I guess it also depends on what format you start with __________________________________
CORNBLOSSOM

Thanks for reply.

My GoPro Hero-2 gives me ... 1080T 30 fps Wide ( 1920x1080 ) at 11MP'ls with a *.mp4 output file.
My Nikon CoolPix S-8000 puts out a video..... (1280x720 ) 29fps with a *.mov output file.
I edit with CyberLink Power Director 11.

Some of my You Tube videos seem kind of blury. If I view them on my VLC Media Player, they look much sharper.
The latest video that didn't seem as sharp as I would have liked was put on You Tube as a *.m2ts file. Ageing Gracefully

I believe m2ts is mpeg 2, so YouTube probably encodes it to mp4,, so you loose a little quality. __________________________________
CORNBLOSSOM

.m2ts is mpeg4 so there's no loss of quality. You can use that format or .mp4 to upload to YT in full HD.

One thing to check if you think your videos aren't playing sharply on YT is to click the gear (settings) icon on the lower right side of the bottom edge of the screen. From there, you should be able to change the playback quality up to the full resolution that you uploaded (1080p for the GoPro and 720p for the Nikon).

If you have a slow internet connection you might have buffering/playback issues, but you should see the clip in full detail.

YouTube/optodata

DS365 | Win11 Pro | Ryzen 9 3950X | RTX 4070 Ti | 32GB RAM | 10TB SSDs | 5K+4K HDR monitors

Canon Vixia GX10 (4K 60p) | HF G30 (HD 60p) | Yi Action+ 4K | 360Fly 4K 360°

I have re-done my latest video to a mp4 and uploaded it to You tube.

I do try the higher quality settings while playing the video on You Tube. Even though I have Comcast hi-speed service, I sometimes get hesitation when playing at 1080, sometimes at 720 it will hesitate. There's option for a faster internet connection, but it's expensive enough, as it is, to have Comcast service.

These videos play great on my computer in VLC Media Player or Windows Media Player.

I just read that clearing my cookies, browsing history , etc. to free up buffer space, will help playing at higher quality settings. Tried it and seems to help play at 1080.

Thanks for suggestions. Ageing Gracefully

Smooth playing videos on Youtube is hit and miss. Depends on many, many factors.

Internet congestion, Youtube congestion, Your internet connection.
In some cases, the speed of your computer.

I have seen slow computers never get a smooth play from Youtube.

720P works best for my system. I can play 1080P, but it is not smooth.

Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.