YouTube 16:9 resolutions 240p to 8K and what Timeline renders

YouTube lists eight encode sizes for its default 16:9 ratio, from 426x240 up to 7680x4320. Sume's Timeline can render four of them: 1920x1080, 1280x720, 854x480 and 640x360. The other four fail the documented limit of even edges between 256 and 2160, because three are too wide and 240p is too short.

YouTube's ladder against Timeline

The list is YouTube's own recommendation for encoding at the default 16:9 ratio. YouTube also notes that in 2022 it began removing playback support for resolutions between 4K and 8K, so something like 5K may no longer play.

The check

Timeline's width and height must be even integers from 256 to 2160. That excludes 4K and 1440p by width, 8K by both edges, and 240p by height. This script applies the same test to each rung.

import asyncio

LADDER = {
    "8k": (7680, 4320), "4k": (3840, 2160), "1440p": (2560, 1440),
    "1080p": (1920, 1080), "720p": (1280, 720), "480p": (854, 480),
    "360p": (640, 360), "240p": (426, 240),
}

def renderable(w, h):
    return all(256 <= v <= 2160 and v % 2 == 0 for v in (w, h))

async def main():
    for name, (w, h) in LADDER.items():
        print(name, w, h, "ok" if renderable(w, h) else "outside 256-2160 even")

asyncio.run(main())

Where 4K can come from

4K is not out of reach for Sume overall. The Video Router docs list gemini-omni-flash-1.1 at 360p, 720p, 1080p and 4K for clips of 3 to 10 seconds in 16:9 or 9:16. That is a generation resolution, so a 4K clip would come straight from that model and not through Timeline. Check capabilities on GET /v1/video-router/models for the model you plan to call.

Practical picks

• Long-form with Timeline: render 1920x1080 and let YouTube make the lower rungs.
• Low-bandwidth previews: 854x480 or 640x360 are legal frames.
• 240p needs a different tool, because 240 is below the 256 floor.