add an encoding-settings.json

[gabrielstuff]

The encoding-settings.json should provide a way for the user to understand how media should be encoded.

An example below, heavily inspired by Google Youtube recommendations:

Recommended upload encoding settings

Below are recommended upload encoding settings for your videos.

Container: MP4

• No Edit Lists (or the video might not get processed correctly)
• moov atom at the front of the file (Fast Start)

Audio codec: AAC-LC

• Channels: Stereo or Stereo + 5.1
• Sample rate 96khz or 48khz

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 rate

• Content should be encoded and uploaded in the same frame rate it was recorded.
• Common frame rates include: 24, 25, 30, 48, 50, 60 frames per second (other frame rates are also acceptable).
• Interlaced content should be deinterlaced before uploading. For example, 1080i60 content should be deinterlaced to 1080p30, going from 60 interlaced fields per second to 30 progressive frames per second.

Bitrate

The bitrates below are recommendations for uploads. Audio playback bitrate is not related to video resolution.
1/ Recommended video bitrates for SDR uploads
To view new 4K uploads in 4K, use a browser or device that supports VP9.

2/ Recommended video bitrates for HDR uploads

3/ Recommended audio bitrates for uploads

Resolution and aspect ratio

We use 16:9 aspect ratio players. If you're uploading a non-16:9 file, it will be processed and displayed with either black bars on the left and right (pillar boxes) or black bars at the top and bottom (letterboxes) to make a 16:9 ratio in the player.

[gabrielstuff]

A little introduction text could allow showing directly a preferred format.