Threads video quality: HD, 4K, and the original file
The sharpest save is the file the creator uploaded. A downloader cannot invent detail that was never there.
Threads stores the media the account uploaded and often also a few smaller sizes for previews. When ThreadsVideoDL reads a public post, it keeps the largest image that is not a square crop, and it keeps the video file the post actually offers. The card then says 720p HD, 1080p HD, 4K, or the raw pixel size.
4K is not a mode we turn on. If the frame is not that tall, labeling it 4K would be false. Upscaling a 720p file into a 4K container makes a larger download and a soft picture. We do not do that. HD on this site means the source is at least 720 pixels tall, and 1080p means it is at least 1080.
A screenshot looks worse for a different reason. It photographs the screen, including the interface and whatever compression the phone applies to screenshots. The downloaded JPG or MP4 skips that second camera. It can still look soft if the creator uploaded a soft file. That limit belongs to the upload.
Audio follows the same idea. The soundtrack is extracted as M4A so it is not encoded again as MP3 on the server. A second encode would be another quality loss for no benefit unless you specifically need the MP3 extension.
Links to the media host expire. A file that looked sharp an hour ago can fail until you paste the post again and receive a fresh address. The pixels do not change when the signature on the URL changes.
Frequently asked questions
Why are there many image sizes in the page source?
Threads publishes thumbnails and the larger image. We pick the largest non-cropped candidate we are allowed to request.
Can you make a video sharper?
No. The original upload is the ceiling.