user17386: Target platform: Youtube
Target resolution for audience: Full HD
I record 4K in order to get better image quality from smartphone (2x birate of FullHD).
Should I resample and export the project in Full HD or rather export 4K, upload 4K and let youtube downsample my video ? 
Thank you 

user23732: If you can afford the additional upload and processing time to You Tube, you should use 4k.
Not only will this look better for most people (Not actually look better, but rather it looks more modern to an average user to have 4k and some people don't even watch it if it says FHD). But also, YouTube gives 4k videos a higher bitrate which also FHD videos profit from.
So you will get an better FHD video from downsampling on You Tube, than do it yourself.
If you don't have the time tho to wait for upload and processing, most people won't notice the difference

user14504: YouTube will transcode your files regardless of what you upload. If you upload a 1080 file, it will create its own file using their new codec (which I am not sure is 100% deployed yet but is already widely in use), but its their propritary AV1 codec. 
That said, Lukas above is correct, just upload a 4k if the project was mastered in 4k, and let youtube make its own down converted copies for variable bitrate streaming. 

17386: <p>Target platform: Youtube</p>

<p>Target resolution for audience: Full HD</p>

<p>I record 4K in order to get better image quality from smartphone (2x birate of FullHD).</p>

<p>Should I resample and export the project in Full HD or rather export 4K, upload 4K and let youtube downsample my video ? </p>

<p>Thank you </p>
 23732: <p>If you can afford the additional upload and processing time to You Tube, you should use 4k.
Not only will this look better for most people (Not actually look better, but rather it looks more modern to an average user to have 4k and some people don't even watch it if it says FHD). But also, YouTube gives 4k videos a higher bitrate which also FHD videos profit from.</p>

<p>So you will get an better FHD video from downsampling on You Tube, than do it yourself.</p>

<p>If you don't have the time tho to wait for upload and processing, most people won't notice the difference</p>
 14504: <p>YouTube will transcode your files regardless of what you upload. If you upload a 1080 file, it will create its own file using their new codec (which I am not sure is 100% deployed yet but is already widely in use), but its their propritary AV1 codec. </p>

<p>That said, Lukas above is correct, just upload a 4k if the project was mastered in 4k, and let youtube make its own down converted copies for variable bitrate streaming. </p>
