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Re: Error Resilience & Scalability

RealMedia and Windows
Media can also switch between different data rates during transmission as
bandwidth needs change.

I can't remember it exactly at the moment but wasn't the dynamic switching between different data rates somewhat limited in WM8 because of limitations of the asf file format (only one audio track per file or something like that - I know, I shouldn't read your book during the night)? Provided that I'm right, have there been changes in WM9 concerning that?

But dropped packets themselves are mainly
a problem for modem users,
Not to forget those who want to access video via mobile devices in the future (ok, it's a little bit questionable if people will really use mobile devices to access video on the internet in the near future but that's another story). Error resilience also matters when it comes to real-time communication over ip-networks.

    None of the formats will dynamically reduce resolution due to CPU
limitations.
What about MPEG-4 spacial scalability? If you only decode the base layer of a multilayer bitstream you get a lower resolution image. So wouldn't it be theoretically possible to add or remove the enhancement layers dynamically? (just a thought, I'm not saying that it makes sense doing this dynamically)

MPEG-4's scalable profiles (not widely implemented yet) and
Speaking of MPEG-4 scalable profile implementations: Is there a MPEG-4 scalable profile solution that also supports OS X and Linux?

Windows Media 9 (still in pre-release) can have different resolutions at
different data rates within the same file, though.
I haven't read a lot about WM9 so I'm especially thankful for this kind of information :-)

QuickTime's biggest competitive limitation for streaming is its lack of
robust mechanisms to deal with varying connection speeds.
I hope this will improve with adoption of new MPEG-4 profiles. Although I fear that it will take quite some more time...

Gruss
Marc
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References: 
 >Re: Error Resilience & Scalability (From: Ben Waggoner <email@hidden>)



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