- From: Maciej Stachowiak <mjs@apple.com>
- Date: Tue, 20 Jul 2010 10:22:08 -0700
- To: Henri Sivonen <hsivonen@iki.fi>
- Cc: Leonard Rosenthol <lrosenth@adobe.com>, "julian.reschke@gmx.de" <julian.reschke@gmx.de>, Boris Zbarsky <bzbarsky@MIT.EDU>, "public-html@w3.org" <public-html@w3.org>
On Jul 20, 2010, at 5:28 AM, Henri Sivonen wrote: > On Jul 20, 2010, at 15:14, Leonard Rosenthol wrote: > >> Also consider other packaging systems, such as the MP4 "package" which is used for various video formats - how would a UA know one it supports only via sniffing? It can't! > > Actually, the ISO media container format used for MP4, JPEG 2000, etc. has subtype identifiers near the start of the file. (At constant offsets, I believe--but didn't verify.) In fact, for the ISO container, it's generally necessary to look at these subtype identifiers. While it is possible to use MIME parameters to identify all the codecs inside an MPEG-4 file, this is almost never done in the server-sent Content-Type. Regards, Maciej
Received on Tuesday, 20 July 2010 17:22:42 UTC