vidpickr

Glossary · protocol

What is Range request (HTTP byte range)?

A range request is an HTTP request that asks for a specific byte range of a file rather than the full thing. Sent as a `Range: bytes=0-1048575` header, it returns just that section with HTTP 206 Partial Content. Range requests power video seek, parallel downloads, and resumable transfers.

Also called:byte range · partial content · http range

When you scrub a YouTube video, the player isn't re-downloading the whole video — it's issuing a range request for the bytes near the new playhead position. The CDN returns those bytes with a 206 status code; the player decodes from the nearest keyframe and resumes playback.

Range requests also enable parallel downloads. Instead of one TCP connection pulling the whole file, a downloader can open six connections each fetching a different byte range, then assemble them in order. This bypasses YouTube's per-connection throughput throttle, which kicks in after the first ~10 MB.

VidPickr's server-side stream handler issues parallel range requests when fetching video or audio bytes — that's how it can saturate a 100 Mbps connection on a single download instead of being capped at YouTube's ~5 Mbps per-connection rate.

Common questions

Why are video downloads sometimes faster than the player?
Players use a single connection and YouTube throttles it to roughly playback bitrate. A downloader can open multiple parallel range requests, each in its own throttled stream, and combined they saturate the link.

Related terms

Signed URL

A signed URL is a download link with cryptographic parameters that authenticate the request and expire after a set time.

Fragmented MP4

Fragmented MP4 (fMP4) is an MP4 variant where the file is split into many short chunks ("fragments"), each containing its own header.

VidPickr is a free, browser-based YouTube downloader. Every term in this glossary either describes how YouTube delivers video or why your downloads behave the way they do. Try the downloader →