[2scoops]

Does anyone know what the kbps is for most of the 720p trailers you can download off market place e.g. The X-MEN 3 Trailer.

Also does anyone know how much having dolby 5.1 adds to the kbps.

E.g. if you reduced the 5.1 to stereo only how much would this reduce the bit rate per second?

The main reason for me asking is i downloaded some stereo only wmv - hd video off the net which runs at 4000 kpbs which claimed to be HD but seems much smaller in file size.

What is the ideal Kbps for true WMV -HD??

[meansizzler]

8000kb/s for video on average
Usually 448kb/s for audio but sometimes 384kb/s or 256kb/s

5.1 Audio is WMA Pro 9 not Dolby 5.1, the 360 actually converts the wma signal to dolby so you get a little quality loss, but the 360 can also output native WMA 9 Pro via optical if your amp supports it, check in the system settings audio panel...

[2scoops]

thanks, is there any minimum bittrate for WMV - HD, could we say anything below 8000 kbps isn't WMV-HD?

[digitalsafari]

I do High Definition encoding and Microsoft's spec for WHM-HD for Live Marketplace is-

High Definition Video 720p/30
Video codec WMV 9
Video Resolution: 1280x720
Video Bitrate: 6000kbps – 8000kbps CBR
Framerate: 30fps (29.97 or 24fps for film source)

Audio Codec Windows Media Audio 9.1 Professional
5.1 channels, 384kbps CBR

For Europe we can also use 720p 50/25.

[2scoops]

From your experience of HD encoding would you consider a 4000kbps WMV file HD quality?

[digitalsafari]

Originally Posted by 2scoops

From your experience of HD encoding would you consider a 4000kbps WMV file HD quality?

Bitrate does not determine if something is HD or not.

The quality a given bitrate will deliver will be down to picture content, source quality, pre-filtering, encoder quality etc.

[2scoops]

I managed to the find the answer in Microsofts WMV - HD encoding guide it states the following:

"The video bit rate should be as high as the capacity of the DVD disc allows. However, 5 megabits per second (Mbps) should be the minimum for 720p, and 6.5 Mbps is minimum for 1080p. Encoding 720p at 7 to 9 Mbps and 1080p at 8 to 9 Mbps is ideal."

Therefore the file i downloaded at 4000kbps (4Mbps) can't really be considered a true WMV - HD compliant file (not far of admittedly though) it did look good but not quite as good as the WMV - HD clips i've downloaded of Microsofts website.