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Documentation Index

Fetch the complete documentation index at: https://vidow.io/docs/llms.txt

Use this file to discover all available pages before exploring further.

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Streaming & Video

A video delivery protocol originally created by Apple and now the dominant streaming format across the web. HLS works by splitting a video into a series of short segments and pointing to them through a text-based index file called an m3u8 manifest. Players fetch segments one at a time over standard HTTP, which means the stream works through firewalls and CDNs without any special infrastructure. Because multiple quality versions of the same segments exist, the player can step up or down in resolution on the fly as your connection changes.
An open-standard adaptive streaming protocol that works on the same principles as HLS but uses an XML-based index file called an MPD. Whereas HLS was initially Apple-proprietary, DASH was designed from the ground up as a vendor-neutral specification, and many large platforms use it alongside or instead of HLS. From a user perspective the experience is identical — quality adjusts automatically and playback happens over ordinary HTTP.
The file extension that identifies an HLS playlist. It is a plain-text file structured as an extended M3U playlist, containing the addresses of each video segment along with duration hints and, in master playlists, links to alternate quality renditions and audio tracks. When Video Downloader Plus encounters an m3u8 URL in network traffic, it recognises an HLS stream and can begin assembling a complete download from all the listed segments.
The XML manifest format used by DASH streams, analogous to the m3u8 file in HLS. An MPD describes every available quality tier, frame rate, audio language, and subtitle track, along with the exact byte ranges or URLs that correspond to each segment. Video Downloader Plus parses MPD files to identify all representations and select the highest-quality stream for download.
A delivery strategy where video is pre-encoded at several quality levels — for example 360p, 720p, and 1080p — and each level is sliced into identically timed segments. The player monitors real-time throughput and buffer health, then requests segments from whichever quality tier keeps playback smooth. If your bandwidth drops, it steps down; when bandwidth recovers, it steps back up. Both HLS and DASH are built around this principle. Video Downloader Plus downloads the highest available tier by default, giving you the best copy the source offers.
The straightforward alternative to adaptive streaming: a single video file served at a fixed URL, downloaded linearly from byte zero to the end. The browser knows the total file size upfront and can display a deterministic progress bar. Progressive downloads are simpler to capture because the entire video is one resource rather than hundreds of segments — Video Downloader Plus handles both approaches automatically.
The individual short-duration video chunks — typically two to six seconds each — that adaptive streams are divided into. Each segment is a self-contained, independently decodable unit, which is what makes quality switching possible mid-stream. When Video Downloader Plus downloads an HLS or DASH stream, it fetches every segment in sequence and then joins them into a single continuous output file.
A generic term for the index file that describes an adaptive stream’s structure. The manifest lists the available quality levels, the URL or byte range for each segment, and any supplementary tracks such as alternate audio languages or subtitle streams. HLS manifests are m3u8 files; DASH manifests are MPD files. Video Downloader Plus’s detection logic targets manifest requests because intercepting the manifest gives access to the entire stream.
Short for multiplexing — the operation of combining separate elementary streams (most commonly a video track and an audio track) into one output file. Many adaptive streams deliver audio and video as entirely separate segment sequences so that players can mix and match video resolution with audio language independently. Video Downloader Plus automatically muxes the appropriate tracks together during download so you receive a single, properly synchronised file.
Changing a video’s container format without touching the encoded content inside. During transmuxing, the raw compressed frames are extracted from one wrapper and repacked into another — for instance, moving MPEG-TS data from HLS segments into an MP4 container. Because no decoding or re-encoding takes place, transmuxing is fast and causes zero quality loss. Video Downloader Plus transmuxes HLS segment data into standard containers during download, giving you a universally compatible file without degrading the original encoding.
The file format that acts as a wrapper around compressed audio and video data. The container defines how tracks are interleaved, how metadata is stored, and what codecs are supported. Common containers include MP4, MKV, MOV, and WebM. Two videos can use the same codec yet be in different containers, and the same container can hold content encoded with different codecs. The container determines the file extension you see; the codec determines the compression algorithm inside.
The compression algorithm used to encode and decode audio or video. Codecs dramatically reduce file size compared to raw video by exploiting spatial and temporal redundancy between frames. Widely used video codecs include H.264 (AVC), H.265 (HEVC), VP9, and AV1. Each generation offers better compression efficiency at the cost of higher computational complexity. The codec lives inside the container and is independent from it — an MP4 file can hold H.264, H.265, or AV1 content.
Fully decoding a video from its original codec and then re-encoding it using a different codec or different encoding settings. Transcoding is computationally intensive and always involves some generation loss, because you are making new compression decisions on already-compressed data. It is the right tool when you need to change codec (e.g., H.264 to AV1) or drastically reduce file size, but the wrong tool when you just need a different container — use transmuxing instead.

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File Formats

The MPEG-4 Part 14 container is the closest thing the video world has to a universal format. It plays natively on every major operating system, browser, smart TV, and mobile device without any additional software. MP4 typically wraps H.264 or H.265 video and AAC audio, striking a balance between file size and broad compatibility. It is Video Downloader Plus’s default output format for this reason.
The Matroska Video container is an open-source format built to hold virtually any combination of video codecs, audio tracks, subtitle streams, chapter markers, and attachment files in a single package. MKV’s flexibility makes it popular for storing high-quality video collections and for use with media servers like Plex or Jellyfin. Playback on stock mobile or browser environments may require additional codecs or a third-party player.
An open container format developed by Google specifically for web delivery, designed to pair with the VP8, VP9, or AV1 video codecs and the Vorbis or Opus audio codecs. WebM files are typically smaller than equivalent MP4 files at the same perceived quality, which benefits bandwidth-constrained streaming. Native browser support is excellent, though some older devices and editing applications do not recognise it.
Apple’s QuickTime container format, which predates MPEG-4 and served as one of its primary inspirations. MOV files play natively across macOS and iOS and integrate seamlessly with Apple’s professional software ecosystem, including Final Cut Pro and Logic Pro. The format supports the same H.264 and H.265 codecs as MP4 and uses a nearly identical internal structure, though the two are not freely interchangeable without remuxing.
MPEG Transport Stream is the low-level container that HLS uses for its individual segments. It was originally designed for broadcast television, where robustness against packet loss mattered more than file efficiency. Raw HLS downloads produce .ts files. While many media players can handle .ts files directly, Video Downloader Plus converts them to MP4 or another standard container during download to maximise compatibility.

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Cloud Storage

An industry-standard authorisation framework that lets you give Video Downloader Plus permission to write files to your cloud storage account without ever sharing your password. Instead of credentials, the service issues Video Downloader Plus a scoped access token that covers only the specific operations you approved — typically uploading files to a folder. You can revoke this token at any time from your Google Drive or Dropbox security settings, instantly cutting off Video Downloader Plus’s access.
A technique used by object storage services like AWS S3 and Cloudflare R2 where a large file is broken into numbered parts and each part is uploaded independently, often in parallel. Once all parts are confirmed as received, the service reassembles them server-side into a single object. This approach tolerates network interruptions gracefully — a failed part can be retried without restarting the entire upload — and dramatically speeds up transfers for files over 100 MB.
An upload protocol, most commonly associated with Google Drive’s API, that maintains a server-side session so an interrupted transfer can continue from its last confirmed byte rather than from the beginning. When Video Downloader Plus starts a Google Drive upload, it opens a resumable session URL. If your network drops or the browser tab is closed and reopened, Video Downloader Plus queries how many bytes were received and picks up exactly where the transfer stopped.
Charges that cloud storage providers levy when data leaves their infrastructure — typically when you download a file or when a CDN serves it to end users. AWS S3 charges egress fees per gigabyte transferred out. Cloudflare R2, by contrast, has no egress fees, which makes it significantly cheaper for use cases that involve frequent retrieval of stored videos. This cost difference is one reason Video Downloader Plus surfaces R2 as a storage option alongside S3.

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Browser & Web

A category of web application that loads once and then updates the visible content by manipulating the DOM rather than requesting entirely new pages from the server. Navigation feels instant because only data — not full HTML documents — travels over the wire. Frameworks like React, Vue, and Angular are commonly used to build SPAs. Because the page never fully reloads, a browser extension must actively watch for URL and DOM changes to detect newly loaded video players. Video Downloader Plus is built to handle SPA navigation without missing embeds that appear after the initial load.
A family of technologies that encrypt video streams so that only authorised playback environments can decrypt and render them. Common DRM systems include Widevine (Google), FairPlay (Apple), and PlayReady (Microsoft). Encrypted streams are useless without the corresponding decryption key, which is tied to the licensed player environment and never exposed to extensions or third-party software. Video Downloader Plus does not attempt to bypass or circumvent DRM — content protected this way is simply not available for download.
A background script used by modern browser extensions (Manifest V3) to handle tasks like network monitoring and state management without requiring an open tab. Video Downloader Plus uses a service worker to detect video streams as you browse.
The current Chrome extension platform specification, replacing the older Manifest V2 standard. Manifest V3 improves security and performance by using event-driven background scripts and declarative rules for network operations. Video Downloader Plus is built on Manifest V3 for compatibility with all modern Chromium browsers.