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 Alpha channel in mediafiles 
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Post Alpha channel in mediafiles
One thing to remember is that the size can NOT in height go over 576 pixels ( why?, that´s a issue I hope that will be solved)
You can do a 1920 x 576 pixel files with alpha that works. If you make it 1920 x 577 or more, it will not contains alpha.

For Stage models it seems that the maximun height is 384 pixels, why? I don´t know really!!

Alpha should work great in sprite mode

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Peppe Tannemyr
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Wed Aug 06, 2008 9:12 pm
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Post Re: Alpha channel in mediafiles
Peppe. According to the release notes for 3.0.12 this issue on the stage is now resolved. Release notes say: "- fix: Stage now allows pal media with alpha channels to be used without going over resolution limit of system."

The issue was originally related to the fact that using Alpha channels would double the height of the encoded version of the clip and the dongle thought the resulting media was outside the range of the licence. The system will now disregard this.

One other related issue was fixed too due to several tech support calls on this problem. Release notes say: "- fix: Default option to preserve alpha now changed to "false" " This makes good sense because many content cretion studios leave ALPHA channels on in source media even if you don't need it so you would be unaware that you were creating unnecessarily large files, slowing the system and eating up storage space.


Mon Jan 05, 2009 6:35 pm
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Post Re: Alpha channel in mediafiles
Ok, great!! But still the Critter having the old limits??
Yes it´s looks like that since I just tested out some 1024 x 520 clips with alpha and they was not imported with the alpha.

Alpha is great for logotypes that are moving or similar stuff, often you are happy with a png, but often the stuff are animated and "screen" is not good enough!

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Peppe Tannemyr
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Mon Jan 05, 2009 7:47 pm
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Post Re: Alpha channel in mediafiles
Peppe, as per the above post, did you check that 'preserve alpha transparency' was ticked i the media manager settings? As discused, it's now turned off by default.

As for the questions regarding HippoCritter, the software it is running is not the final version for HippoCritter and henc I can't comment. I'm sure others will be along to answer that.

And finally, yes Alpha is great! In it's absence I tend to use luma and take the level to around 80% which works well but stinks if your logo has black in it as well as the background as you can't be selective over the areas affected.


Mon Jan 05, 2009 11:08 pm
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Post Re: Alpha channel in mediafiles
of course I have checked that!!!
It must b e then the Critter as I understand!

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Peppe Tannemyr
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Tue Jan 06, 2009 12:13 pm
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Post Re: Alpha channel in mediafiles
I have tested but I have the same problem! I think it must be the HippoCritter since I have done the files correct ( as adviced by Peppe )

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Thu Mar 19, 2009 1:47 pm
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Post Re: Alpha channel in mediafiles
As the guys from Green Hippo told me:

You are right there is a bug on the critters which is being fixed on the 3.0.13.

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Peppe Tannemyr
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Thu Mar 19, 2009 1:49 pm
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Post Re: Alpha channel in mediafiles
hello everyone,

yes there is a bug in the Critter yes yes..
I started to avoid alpha a long time ago already because of that earlier limitation.
I do use alpha in still images but in videofiles I usually ask for green areas instead of alpha channels and then just key out green, works as a charm and you do not have those resolution limitations to think about and the files gets encoded much faster thatn with alpha.
Anyway, I am sure the guys at G-H gets this fixed.
This just as an idea how to get it done another way..

Johan West


Fri Mar 20, 2009 6:48 pm
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Post Re: Alpha channel in mediafiles
Anyway, it all works now in V3.013 !
And also the limit of sizes seems to be solved as well so.....

MPEG2 does not support transparency, so Hippo actually take the original file and create 2 files from it – one with colour data and the other with just the Alpha data, we then glue the two images on top of each other on a per-frame basis so that every frame of video is actually now twice it’s original height (colour at the bottom and alpha at the top) and because tyhe maximum sixe of an MPEG2 clip is 1920 x 1152, that means that the original file acannot be more than 576 (1152 / 2) high.

To preserve the alpha transparency of a clip you must enable it in the Media Manager encoding settings:
This can be found by opening Media Manager and selecting "Encoding Settings".
Then selecting the "preserve alpha transparency" tick box.
Please note: When uploading clips with alpha transparency that there are different size limits per product. See below:

Hippotizer Express: * x 288
Hippotizer Stage: 1920 x 384
Hippotizer HD: 1920 x 576
HippoCritter: * x 288

*Products horizontal pixel limit is 1024, anything over that will not be visible at one time but is supported up until 1920.

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Peppe Tannemyr
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Mon Jul 06, 2009 11:12 am
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