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Re: video/@src vs application/octet-stream

From: Henri Sivonen <hsivonen@iki.fi>
Date: Tue, 20 Jul 2010 15:28:59 +0300
Cc: "julian.reschke@gmx.de" <julian.reschke@gmx.de>, Boris Zbarsky <bzbarsky@MIT.EDU>, "public-html@w3.org" <public-html@w3.org>
Message-Id: <D9D30F7B-7C22-4EE7-9B52-C9871893F76C@iki.fi>
To: Leonard Rosenthol <lrosenth@adobe.com>
On Jul 20, 2010, at 15:14, Leonard Rosenthol wrote:

>> In general, binary formats have magic numbers that are always at least an epsilon more reliable than MIME types
> The problem in today's world with this simplistic solution is the use of ZIP as packaging system.   There are NUMEROUS formats (many of which are international standards) in existence today that use ZIP, which means that they will also "sniff" as the same magic number.  As such, you can't rely on sniffing in this case.

Yeah, it's a problem that for zip-based formats, you need the file name or you need to look inside the zip file.

> 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.)

Henri Sivonen
Received on Tuesday, 20 July 2010 12:29:34 UTC

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