HLS recommended segment size is 10 seconds. Is that for VOD only or for live IPTV as well?

>HLS segment size is 10 seconds.

Where did you find that spec? Citation?

>is that for VOD only or for live IPTV service as well? (or is there a different recommended segment size for HTTP live streaming)

From TN2224:

Workflow/Overview/Segment the media

HTTP Live Streaming sends audio and video as a series of small files, typically of less than 10 seconds duration, called media segment files. An index file, or media playlist, gives the clients the URLs of the media segment files.

For video on demand from prerecorded media, Apple provides a free tool to make media segment files and media playlists from MPEG-4 video or QuickTime movies with H.264 video compression, or audio files with AAC or MP3 compression. The media playlists and media segment files can be used for video on demand or streaming radio, for example.