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[whatwg] Codecs (was Re: Apple Proposal for Timed Media Elements)

From: Kevin Calhoun <kcalhoun@apple.com>
Date: Fri, 23 Mar 2007 09:06:30 -0700
Message-ID: <B4701BD3-3C61-4F45-A33F-BE50E2D2BCB7@apple.com>

On Mar 23, 2007, at 8:29 AM, Maik Merten wrote:

> Kevin Calhoun schrieb:
>> Just a quick correction here: QuickTime does support the MPEG-4
>> container format.
>
> Okay, thanks for pointing that out so confusion doesn't spread.
>
> When thinking of QuickTime I was mostly thinking of older .mov files
> that you can still see floating around here and there and do not  
> contain
> MPEG codecs. IIRC the MPEG4 container was more or less derived from
> QickTime's .mov container, so I'm not sure if .mov actually *is*
> actually the MPEG4 container by now.

They're still distinct in a number of particulars. For example MPEG-4  
refines a number of details in the way that media streams are  
described. These refinements are very nice but couldn't be shoehorned  
back into the .mov file format without introducing software  
compatibility problems.

One of the main differences it that the MPEG-4 container format  
specification imposes restrictions on the types of audio and video  
objects it accepts, so while a well-formed QuickTime movie file can  
carry WMV, for example, an MPEG-4 file cannot.

Anyway it appears that I got your original assertion backwards. Thanks  
for the clarification.
Received on Friday, 23 March 2007 09:06:30 UTC

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