Codec

[Andreas Wittenstein]

David,

Thanks for reporting these test results.

SheerVideo really is perfectly lossless, so if you’re seeing any differences, something else must be going on. It sounds typical of color-standard or gamma misspecification, but it could also be RGB->Y’CbCr color conversion or 4:4:4->4:2:2 chroma subsampling. I’d love to help you figure out what it is, but I for that need more information:

[Hans Vernhout]

Andreas,

Thanks for your info. Just one more question, as the SheerVideo codec looks very interesting (like AVID’s DNxHD codec, but for the rest of us)!

[Andreas Wittenstein] “SheerVideo doesn’t currently run in the Kona2 firmware.”

What does this mean? And will it change soon or ever?
So Apple AND Aja have to accomodate to release the full potential of the SheerVideo codec for realtime use on the Kona2?

Keep up the good work!

Hans Vernhout
Director / lighting cameraman
The Netherlands

[Andreas Wittenstein]

In software, the entire SheerVideo package currently takes up several megabytes, and rising. But this is only because there are so many different pathways, differing among parameters such as {RGB, Y’CbCr}, {no Alpha, Alpha}, {10b, 8b}, {4:4:4, 4:2:2}, {p, i}, {encode, decode, transcode}, {scalar, vector}, {many pixel formats}.

SheerVideo was designed to be featherweight for hardware or firmware implementation. In software, each pathway takes only a few KB each for code, data, and image buffer. The code uses only operations which are easily implemented in firmware. And it operates not just in real time, but with ultra-low latency.

As RT Extreme and the Kona2 demonstrate, there are definite advantages to having certain graphics operations done in a graphics or video card. SheerVideo may run ever so fast in the host CPU, but at HD data rates, merely accessing the data strains the limits of today’s CPUs.

[Andreas Wittenstein]

David,

A couple of days ago we released a new version (v2.4.0) of SheerVideo that may fix the color-shift problem you discovered.

SheerVideo had only been specifying the QuickTime color parameters essential to Synchromy, in the assumption that the remaining parameters would be filled in as appropriate by QuickTime and the application. This assumption was sometimes unwarranted, resulting in color shifts due to incorrect parameter settings. Thus SheerVideo now specifies all the color parameters itself.

In order to do so, SheerVideo needs the user to provide enough information to determine all these parameters. Happily, the familiar standards NTSC, PAL, HD, and HD 1035 cover all the necessary parameters, so the Sheer Options settings now use these terms in place of the previous obscure ITU and SMPTE standards.

Nevertheless, QuickTime Player somehow still manages to use the wrong color standard when converting ‘v210’ (Y’CbCr 10bv 4:2:2) output from the Sheer Y’CbCr 10bv decoders to ‘2vuy’ (Y’CbCr 8bv 4:2:2) for display, again resulting in a color shift. Fortunately, there is a simple workaround, which is to let SheerVideo output ‘2vuy’ directly, which is typically much faster anyway. To do this, you need to turn off High Quality in the Sheer video track before displaying it. (Turning High Quality on directs SheerVideo to accept only pixel formats to which it can decode without information loss, but displaying 10-bit data on an 8-bit display necessarily involves information loss.) For instructions, see

https://www.bitjazz.com/sheervideo/support/manual/quicktime_player/playback.shtml

Note: BitJazz Inc. has a policy of rewarding those who help us improve our products. The users who reported these problems and gave us enough information to isolate and fix the bugs received complimentary SheerVideo Pro licenses in return.

[Marco Solorio]

[Andreas Wittenstein] “Note: BitJazz Inc. has a policy of rewarding those who help us improve our products. The users who reported these problems and gave us enough information to isolate and fix the bugs received complimentary SheerVideo Pro licenses in return. “

And let me add that Andreas is a very appreciative and generous person. He’s definitely an asset to our community without question.

Marco Solorio  |  OneRiver Media

[David Battistella]

Andreas,

I have downloaded the new codecs and I will give them a go this week.

David