English Amiga Board - View Single Post - Photon video Cel animator

DDNI · 07 August 2011, 08:41

Yes I explained that my archive contained the angel.anim in post 30 of this thread.

There has been a bit of recent work done on getting the .anim to display better.
The angel.anim when viewed here, used to have bad HAM fringing.

Walter Randelshofer has fixed this now. The cause is explained below:

The reason for the fringing was the way the colors were stored by Photon Video Cel Animator.
Instead of using the same low and high bit per color (which is usual for OCS color palettes), the high bit wasn't set at all.
For example, a value for an orange color should look like this #EE7711, but it was stored as #E07010.
Since OCS Amigas will ignore the high bit anyway you won't see any difference.
It will also be displayed correctly in DPaint, because it is also checking the 'CAMG' chunk of an IFF file.
This chunk tells if the image was created on an Amiga with OCS, ECS or AGA chip set.
In case of the OCS chip set, the value of the low bit will automatically used for both, the high and low bit.
However, the applet was displaying the color palette exactly as defined. The result were slightly darker HAM base colors.
As you know, additional colors in HAM can be defined by altering the RGB values of the previous pixel.
In order to display images correctly it is crucial to get the color palette right, especially on HAM images.
The updated applet version is now taking care of the CAMG entry and makes sure OCS colors are handled accordingly.

07 August 2011, 08:41	#42
DDNI Targ Explorer Join Date: Mar 2006 Location: Northern Ireland Posts: 5,433	Yes I explained that my archive contained the angel.anim in post 30 of this thread. There has been a bit of recent work done on getting the .anim to display better. The angel.anim when viewed here, used to have bad HAM fringing. Walter Randelshofer has fixed this now. The cause is explained below: The reason for the fringing was the way the colors were stored by Photon Video Cel Animator. Instead of using the same low and high bit per color (which is usual for OCS color palettes), the high bit wasn't set at all. For example, a value for an orange color should look like this #EE7711, but it was stored as #E07010. Since OCS Amigas will ignore the high bit anyway you won't see any difference. It will also be displayed correctly in DPaint, because it is also checking the 'CAMG' chunk of an IFF file. This chunk tells if the image was created on an Amiga with OCS, ECS or AGA chip set. In case of the OCS chip set, the value of the low bit will automatically used for both, the high and low bit. However, the applet was displaying the color palette exactly as defined. The result were slightly darker HAM base colors. As you know, additional colors in HAM can be defined by altering the RGB values of the previous pixel. In order to display images correctly it is crucial to get the color palette right, especially on HAM images. The updated applet version is now taking care of the CAMG entry and makes sure OCS colors are handled accordingly. Last edited by DDNI; 07 August 2011 at 09:00.