WMV-HD encoding with CBR

[tominator]

Hi
I would like some help with good specs for WMV-HD encoding with CBR. The files are going to be used for streaming over internet which is my I can't use VBR.

How low bitrate-wise can one go and still call it HD?

All the info Ive found has been aimed for VBR-encoding so any help at all would be great.

Also, I remember reading an article on microsoft.com where they stated that one should use 1-pass for encoding HD. For some reason the bits would be distributed better that way. Does anyone know if this is still true?

[zambelli]

Hi
I would like some help with good specs for WMV-HD encoding with CBR. The files are going to be used for streaming over internet which is my I can't use VBR.
If you're planning on using it for streaming, make sure you use a buffer no longer than 8-10 seconds in order to avoid long buffering times during playback. An 8 second buffer is a good start.

How low bitrate-wise can one go and still call it HD?
HD isn't defined by bitrate, but by resolution. 1280x720 is the minimum for HD (could be less than 720p though if the content is wider than 16:9 and cropped). Which bitrate you use will depends on bandwidth available and acceptable quality level.

Also, I remember reading an article on microsoft.com where they stated that one should use 1-pass for encoding HD. For some reason the bits would be distributed better that way. Does anyone know if this is still true?
No, can't think of any reason why that would still hold true.

Make sure you read the WMV9/VC-1 FAQ at the top of this forum. It'll probably answer a lot of your initial questions.

[vsv]

Ben Waggoner did encode of Elephants Dream 1280x720p at 2Mbps (156MB) (http://download.microsoft.com/download/9/b/4/9b4535e2-f908-4785-97a5-ef360405e391/Elephant's%20Dream%20720p%202M.wmv)

[benwaggoner]

Ben Waggoner did encode of Elephants Dream 1280x720p at 2Mbps (156MB) (http://download.microsoft.com/download/9/b/4/9b4535e2-f908-4785-97a5-ef360405e391/Elephant's%20Dream%20720p%202M.wmv)
Although that was a VBR encode.

But I've done a variety of clips at 720p24 at 3-4 Mbps CBR with very high quality.

[tominator]

Although that was a VBR encode.

But I've done a variety of clips at 720p24 at 3-4 Mbps CBR with very high quality.

What software did you use for those encodes?

Would it be possible to get some example clips + settings used for each? That would be great.

Also, I read this article that you seem to have written:
http://www.microsoft.com/windows/windowsmedia/howto/articles/encodingforhd.aspx

"CBR supports both one-pass and two-pass encoding. For Web data rates, if at all possible, use two-pass encoding. This lets the codec have a complete measurement of all the frames in the file, enabling it to provide optimal distribution of bits.

For the purposes of HD, however, use one-pass CBR. A one-pass CBR encode estimates how the video will change in the future, and sometimes that estimate is wrong. With the high data rates of HD, the estimate that one-pass CBR gives is actually better than two-pass CBR with today's Windows Media Video 9 codec. However, future Microsoft codecs will support other modes as well."

Is this still true? Or can I disregard that if I do VC-1?

[benwaggoner]

What software did you use for those encodes?
Alex's WMCmd.vbs

Would it be possible to get some example clips + settings used for each? That would be great.
I'll try to squeeze in an Elephant's Dream of that in CBR mode for yah.

Also, I read this article that you seem to have written:
http://www.microsoft.com/windows/windowsmedia/howto/articles/encodingforhd.aspx

"CBR supports both one-pass and two-pass encoding. For Web data rates, if at all possible, use two-pass encoding. This lets the codec have a complete measurement of all the frames in the file, enabling it to provide optimal distribution of bits.

For the purposes of HD, however, use one-pass CBR. A one-pass CBR encode estimates how the video will change in the future, and sometimes that estimate is wrong. With the high data rates of HD, the estimate that one-pass CBR gives is actually better than two-pass CBR with today's Windows Media Video 9 codec. However, future Microsoft codecs will support other modes as well."

Is this still true? Or can I disregard that if I do VC-1?
Wow, I wrote that years ago! I'll need to get that edited.

Yes, we're already living in the future :). The 2-pass modes are just fine to use with the v11 codecs that were released last fall.

[tominator]

Alex's WMCmd.vbs

I googled that but didnt get any results at all :/

I'll try to squeeze in an Elephant's Dream of that in CBR mode for yah.

That would be great.

Wow, I wrote that years ago! I'll need to get that edited.

Yes, we're already living in the future :). The 2-pass modes are just fine to use with the v11 codecs that were released last fall.

Hehe :) Do you happen to have written any newer guides on how to encode HD with VC-1 and so on?

I saw that you are going to teach a course at Stanford. I live in Sweden and would like to go to some sort of video compression-basics course. You wouldn't happen to know about anything good in my area? (Sweden or somewhere in Europe).

I also saw that you have written a book on video compression. Judging from the comments on Amazon it looks too advanced for me at the moment. Would you happen to know about any good books covering the basics?

[Schrade]

I googled that but didnt get any results at all :/

http://www.citizeninsomniac.com/WMV/#WMCmd

[tominator]

http://www.citizeninsomniac.com/WMV/#WMCmd

Thanks!

[Schrade]

Thanks!
Also there's a support thread on this forum here: http://forum.doom9.org/showthread.php?t=123812

[benwaggoner]

Hehe :) Do you happen to have written any newer guides on how to encode HD with VC-1 and so on?
I've been doing a series of compression tutorials on my blog. This one gives a full scenario for 1080p24 WMV encoding. Although the peak bitrate is higher than I'd use for PC playback. 15 Mbps peak would be a better choice to work on a broader range of machines.

http://on10.net/Blogs/benwagg/elephants-dream-sample/

I saw that you are going to teach a course at Stanford. I live in Sweden and would like to go to some sort of video compression-basics course. You wouldn't happen to know about anything good in my area? (Sweden or somewhere in Europe).
Nothing equivalent. I've talked to some folks about doing a European version, but we never got the details worked out.

I also saw that you have written a book on video compression. Judging from the comments on Amazon it looks too advanced for me at the moment. Would you happen to know about any good books covering the basics?
This is my favorite one readily available:

http://books.elsevier.com/uk/focalbooks/uk/subindex.asp?isbn=9780240806303&country=United+Kingdom&community=focalbooks&ref=&mscssid=7746VH05V0J09L2SDLH7LSKABKX79Q5C

I'm about a year late on my 2nd edition - working from home with three kids hasn't proven to make for very good writing time :).

[tominator]

Thanks a lot! :)