Re: [AVT] Re: IESG Review of draft-ietf-avt-mpeg4-simple-07.txt

Hello John,

Thanks for commenting. 

> Do "MPEG-4 scripts" give the script control over audio volume of the 
> presentation, in a way that could override the levels manually set
> by the human listening to the decoder?

In my understanding, MPEG-4 only provides the capability to control the 
presence of audio objects (streams) in a scene, hence the audio level can 
be controlled from zero up to a certain "nominal" level. MPEG-4 does not 
provide the capability to control the volume level at which the user 
"enjoys" the scene. In other words, in my understanding the problem that 
you mention does not exist in MPEG-4.

Best regards,

Jan

John Lazzaro <lazzaro@CS.Berkeley.EDU>
Sent by: 
avt-admin@ietf.org
2003-07-07 09:33 PM

        To:     avt@ietf.org
        cc:     (bcc: Jan vanderMeer/EHV/CE/PHILIPS)
        Subject:        [AVT] Re: IESG Review of draft-ietf-avt-mpeg4-simple-07.txt - Discuss 
Comments
        Classification: 

>  jan.vandermeer@philips.com writes:
>
> As far as I understand these constraints do not allow dangerous ECMA
> script constructs, which means there is no need for an ECMA script
> security model in this context. Below I attached the MPEG-4 annex that
> describes the differences.

Do "MPEG-4 scripts" give the script control over audio volume of the 
presentation, in a way that could override the levels manually set
by the human listening to the decoder?  A rogue program that blows
out the speakers of the victim's terminal seems like a security
risk of some sort, although not of the classical kind since data
and CPU and network are not compromised ... if this is an actual
risk, might be worth warning implementors in the Security
Considerations section ...

-------------------------------------------------------------------------
John Lazzaro -- Research Specialist -- CS Division -- EECS -- UC Berkeley
lazzaro [at] cs [dot] berkeley [dot] edu     www.cs.berkeley.edu/~lazzaro
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Re: [AVT] Re: IESG Review of draft-ietf-avt-mpeg4-simple-07.txt - Discuss Comments