How to watch, upload and embed videos in true 1920x1080 high definition:

Step 1: Upload a HD video to YouTube with the following specifications:

Compression: H.264
Size: 1920x720 px (Full HD/High Definition) or 1280x720 px (720p HD)
Bit Rate: 3000-5000 kbits/sec
Deinterlaced

Step 2: There is no step 2!

To watch videos in HD, choose the option by clicking on the gear symbol below the video.



https://support.google.com/youtube/answer/1722171?hl=en
Here are YouTube's official advanced encoding settings:

Advanced encoding settings

Recommended bitrates, codecs, and resolutions, and more
Container: .mp4

No Edit Lists (or you may lose AV sync)
moov atom at the front of the file (Fast Start)
Audio Codec: AAC-LC

Channels: Stereo or Stereo + 5.1
Sample rate 96khz or 48 khz
Video Codec: H.264

Progressive scan (no interlacing)
High Profile
2 consecutive B frames
Closed GOP. GOP of half the frame rate.
CABAC
Variable bitrate. No bitrate limit required, though we offer recommended bit rates below for reference
Chroma subsampling: 4:2:0
Frame rates

Frame rates should match the source material. For example, content shot in 24fps should be encoded and uploaded at 24fps. Content recorded at 30fps should be uploaded at 30fps. Content shot in 720p60, should be uploaded at 720p60. Content at 1080i 60, should be deinterlaced, going from 60 interlaced fields per second to 30 progressive frames per second before uploading.
Bitrates

Standard quality uploads
Type Video Bitrate Mono Audio Bitrate Stereo Audio Bitrate 5.1 Audio Bitrate
2160p (4k) 35-45 Mbps 128 kbps 384 kbps 512 kbps
1440p (2k) 10 Mbps 128 kbps 384 kbps 512 kbps
1080p 8,000 kbps 128 kbps 384 kbps 512 kbps
720p 5,000 kbps 128 kbps 384 kbps 512 kbps
480p 2,500 kbps 64 kbps 128 kbps 196 kbps
360p 1,000 kbps 64 kbps 128 kbps 196 kbps
High quality uploads for creators with enterprise quality internet connections

Type Video Bitrate Mono Audio Bitrate Stereo Audio Bitrate 5.1 Audio Bitrate
1080p 50,000 kbps 128 kbps 384 kbps 512 kbps
720p 30,000 kbps 128 kbps 384 kbps 512 kbps
480p 15,000 kbps 128 kbps 384 kbps 512 kbps
360p 5,000 kbps 128 kbps 384 kbps 512 kbps
Resolutions

YouTube uses 16:9 aspect ratio players. If you are uploading a non-16:9 file, it will be processed and displayed correctly as well, with pillar boxes (black bars on the left and right) or letter boxes (black bars at the top and bottom) provided by the player. If you want to fit the player perfectly, encode at these resolutions:

2160p: 3840x2160
1440p: 2560x1440
1080p: 1920x1080
720p: 1280x720
480p: 854x480
360p: 640x360
240p: 426x240
The YouTube player automatically adds black bars so that videos are displayed correctly without cropping or stretching, no matter the size of the video or the player.

For example, the player will automatically add pillarboxing to 4:3 videos in the new 16:9 widescreen player size. If the player is re-sized (i.e. when embedded on another website), the same process takes place so that 16:9 videos are letterboxed when the player is sized to 4:3. Similarly, anamorphic videos will be automatically letterboxed when shown in either 16:9 or 4:3 sized players. The player can only do this if the native aspect ratio of the video is maintained.

You can adjust the fit of your video in our player after uploading your video by using formatting tags.

If letterboxing is added to a video before it is uploaded (i.e. in the case of creating a 4:3 video from a 16:9 master), the widescreen player will add pillarbox bars too, resulting in black bars all around the video (windowboxing) and a bad viewing experience (see the diagram below).