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Amiga computer related discussion => Amiga Software Issues and Discussion => Topic started by: Hodgkinson on March 02, 2008, 01:47:07 PM

Title: Problems with FastJPEG
Post by: Hodgkinson on March 02, 2008, 01:47:07 PM

Hi there,
I seem to be experiencing issues with fastJPEG on my A1200 system. When I scroll horizontally, (Stable) horizontal lines of varying lengths and colours appear from the left hand edge of the screen. These lines vary depending on how much I scroll (I’m guessing its something related to the content of the image), and disappear when I return to the left hand edge of an image.

Changing and swapping around screen modes (Inc VGAOnly) and mode promotion etc. doesn't seem to help.

Anyone any ideas?
Could this be hardware related?

Thanks,
Hodgkinson.

Title: Re: Problems with FastJPEG
Post by: Thomas on March 02, 2008, 02:00:25 PM

This is normal behaviour of autoscroll HAM screens.

Bye,
Thomas

Title: Re: Problems with FastJPEG
Post by: Hodgkinson on March 02, 2008, 02:52:08 PM

It is? *phew*.

Out of interest, what actually causes this? Does it relate to the image being displayed?
TBH, I wouldn't of expected this to be *normal* behaviour on a system.


Thanks for the info,
Hodgkinson.

Title: Re: Problems with FastJPEG
Post by: Piru on March 02, 2008, 02:57:51 PM

Amiga Hold and Modify: Advantages and disadvantages (http://en.wikipedia.org/wiki/Amiga_Hold-and-Modify#Advantages_and_disadvantages)

Title: Re: Problems with FastJPEG
Post by: Hodgkinson on March 02, 2008, 04:39:25 PM

Ah ha. Thanks for the link - It all makes sense now.

Always wondered what HAM meant.

If I used a datatype and a datatype viewer for jpg images, would the appearance of the artefact be dependant of whether the viewer/datatype was coded to display in HAM or not?

Ta,
Hodgkinson.