An MS blog has posted this video playback FAQ in regards to the new dashboard update and one aspect has gotten my attention -

3. What exactly does the Xbox 360 support for WMV (VC-1)?

Xbox 360 supports the following for WMV:

· File Extensions: .wmv

· Container: asf

· Video Profiles: WMV7 (WMV1), WMV8 (WMV2), WMV9 (WMV3), VC-1 (WVC1 or WMVA) in simple, main, and advanced up to Level 3

· Video Bitrate: 15 Mbps with resolutions of 1920 x 1080 at 30fps. See question number 6 for more information.

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6. What is the "real" max bit rate, resolution, and frames per second that you support for all the different formats?

Xbox 360 does not specifically block video from playing based on a maximum bit rate, resolution, or frames per second. The maximums listed above for each codec are what we have tested for various video playback sources. Higher rated content will not be blocked, but playback may be less then optimal. Use higher bitrates at your own risk.

So, we know that the 360 uses software emulation (for lack of a better word) to playback HD DVD's and we know that HD DVDs can have a peak data rate up to 32Mbps.

Now this FAQ raises an interesting question with its recommendation of a maximum bitrate of bellow half of what we expect the technology to be capable of coping with flawlessly.

Of course there is the disclaimer that higher bitrate content will not be stopped from playback, but it might be less than optimum?
My question would have to be, does the 360 have the capability to faithfully playback an HD DVD at its full bandwidth without some form of downsampling prior to output?

I guess the best way to test this would be to encode (in VC-1) a suitably high video for playback and using a USB 2.0 portable device, see how well the 360 copes. If it chokes or looks to be downsampled in anyway, then that would surely cast doubt on the 360's credientials for HD DVD playback would it not?
I believe I have everything hardware-wise I need to test this (no HD DVD drive sadly) but I would need the VC-1 codec and some specifications to work by.

Of course this wouldn't just be a VC-1 limitation if true, but thats what we have to work with so...

If anyone else would like to investigate this further or give some insight or just tell me why I'm wrong then please do.

An MS blog has posted this video playback FAQ in regards to the new dashboard update and one aspect has gotten my attention -


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So, we know that the 360 uses software emulation (for lack of a better word) to playback HD DVD's and we know that HD DVDs can have a peak data rate up to 32Mbps.

Now this FAQ raises an interesting question with its recommendation of a maximum bitrate of bellow half of what we expect the technology to be capable of coping with flawlessly.

Of course there is the disclaimer that higher bitrate content will not be stopped from playback, but it might be less than optimum?
My question would have to be, does the 360 have the capability to faithfully playback an HD DVD at its full bandwidth without some form of downsampling prior to output?

I guess the best way to test this would be to encode (in VC-1) a suitably high video for playback and using a USB 2.0 portable device, see how well the 360 copes. If it chokes or looks to be downsampled in anyway, then that would surely cast doubt on the 360's credientials for HD DVD playback would it not?
I believe I have everything hardware-wise I need to test this (no HD DVD drive sadly) but I would need the VC-1 codec and some specifications to work by.

Of course this wouldn't just be a VC-1 limitation if true, but thats what we have to work with so...

If anyone else would like to investigate this further or give some insight or just tell me why I'm wrong then please do.


The short answer is yes it can and does. The limitation was conservative and put in place in case folks went crazy with their own material and quantization settings.

And more to the point, it's harder with AVC CABRAC encoding, which is can do at full bitrate as well.

Thanks for your input.

If there is any ready made and legal VC-1 encodes out there with high bitrates then I'd certainly like to give them a run. What I have seen so far is only around 10Mbit peak.
Short of that I'd still consider creating my own.

I believe MS has been so conservative in recommending bitrates because they worry about people streaming their video files through either a bad wired network or wirelessly. I think things on hard drives or usb flash drives should work fine, even stuff at hd dvd bitrates.

That makes sense especially with 802.11g throughput being less than spectacular for HD streaming.

Found this thread which pretty much puts this topic to rest.

http://www.avsforum.com/avs-vb/showthread.php?t=834539