The following is the list of known issues or limitations of Ant Video downloader. Some of them are intentional, some are being fixed; see also article on Planned features.
Those issues can cause video not being detected, or errors during video download or convert.
If your issue isn't in the list, contact support for more information.
Tabless (e.g. not tied to a specific tab) videos
Video that were loaded not by a tab content but by a background worker. Such videos do not contain a tab identifier, which is a required parameter for Ant Video downloader. Version 4.14 of AVD already supports tabless videos internally, but there's no UI so far to render such videos.
There is no way for you to see in the release version whether video wasn't detected because it is tabless or not.
Browser's VPN is turned on
When you turn on some VPN add-on or built-in VPN feature in your browser, Ant Video downloader browser extension will automatically be using it, but Native app knows nothing about it, so videos will be detected but not downloaded.
If you need to use VPN for your downloads, try using proxy.
Custom video protection on the server side
Sometimes websites reject video detection or download requests even when AVD provides all the necessary data. We track all such cases to get a workaround.
HLS protocol — external audio
HLS client that comes with Ant Video downloader version up to 4.14 does not support external audio streams.
MPD protocol
MPEG-DASH is one of the most technically complicated video streaming protocols. Currently, we do not have our own client for it, and we use a conjunction of ffprobe and ffmpeg tools to detect and download MPD videos. AVD does not parse the output of ffmpeg, so you can't see download progress. Unfortunately, ffmpeg also does not provide 100% full and accurate support of MPD protocols; thus, not all MPD websites are supported.
Errors in implementation, or intended breaking changes of standard protocols on the server side
Not always websites strictly follow streaming protocols standards, sometimes putting breaking changes, non-standard tags, attributes, etc. AVD may not detect such videos or will fail to download it.
Custom streaming protocols
Plenty of web servers use their own, custom streaming protocols, not published anywhere; often combined with security features to prevent reverse-engineering. Typically, those are Asian TV-series / anime / etc. websites. We put support of them on a long shelve so far.
Popular websites are not supported yet
Facebook, Twitter, Reddit, Instagram, etc. — major popular websites usually have a custom or heavily modified standard streaming protocol, or combination of protocols. We're going to need to add support of each of these sites separately; we're working on a cross-protocols feature in AVD which is going to make support of those websites possible.