[whatwg] Video with MIME type application/octet-stream

Julian Reschke julian.reschke at gmx.de
Wed Aug 18 04:47:41 PDT 2010

On 20.05.2010 20:53, Simon Pieters wrote:
> On Thu, 20 May 2010 20:18:43 +0200, David Singer <singer at apple.com> wrote:
>> It's an error to have a parameter that isn't valid for the mime type,
>> so are you suggesting (a) that you throw away the parameter as it's
>> invalid or (b) since it's an error to supply application/octet-stream
>> as the mime type in the first place, we may as well process its
>> invalid parameter in an attempt to recover?
> I'm just suggesting that it should be defined what to do when you get
> application/octet-stream with parameters. I don't care which handling
> that is, or whether it's valid or why the specific handling was chosen.

Picking up an old thread because of 

 From <http://greenbytes.de/tech/webdav/rfc2046.html#rfc.section.1>:

"Parameters are modifiers of the media subtype, and as such do not 
fundamentally affect the nature of the content. The set of meaningful 
parameters depends on the media type and subtype. Most parameters are 
associated with a single specific subtype. However, a given top-level 
media type may define parameters which are applicable to any subtype of 
that type. Parameters may be required by their defining media type or 
subtype or they may be optional. MIME implementations must also ignore 
any parameters whose names they do not recognize."

So, as "codecs" is not defined on application/octet-stream, the 
parameter simply should be ignored, thus the advice in 

"The MIME type "application/octet-stream" with no parameters is never a 
type that the user agent knows it cannot render. User agents must treat 
that type as equivalent to the lack of any explicit Content-Type 
metadata when it is used to label a potential media resource.

In the absence of a specification to the contrary, the MIME type 
"application/octet-stream" when used with parameters, e.g. 
"application/octet-stream;codecs=theora", is a type that the user agent 
knows it cannot render."

is incorrect, because it requires handling "application/octet-stream" 
and "application/octet-stream;codecs=theora" differently (*).

Best regards, Julian

(*) It's also not clear whether the note applies to all parameters or 
just "codecs".

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