volodya@xxxxxxxxxxxxxx wrote:
After looking at and working with Xv, v4l and v4l2 I became somewhat
dissatisfied with the current state of affairs. I have attached a
description of the API that would make (at least) me much happier.
I would very much appreciate comments from interested people..
thanks !
Vladimir Dergachev
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Kernel multimedia architecture
** the latest version can be obtained from **
http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/gatos/km/km.rfc.txt
0) Motivation
v4l, v4l2 and Xv are all suffering from the same problem: attempt to fit
existing multimedia devices into a fixed scheme. The use of pre-defined
structs to describe parameters of device is inherently wrong because
these parameters vary widely. This leads to either bloating of the control
structures with parameters used only by few devices, proliferation of
device-specific ioctl and/or struct versioning. This also makes it increasingly
hard to implement support for new parameters.
The solution, IMO, is to move away from hard-coded models of multimedia
devices and instead allow greater flexibility to driver developers by
providing _symbolic_ interface.
...
I don't know - I don't see anything in the interface design that can do
anything more than v4l2. In fact, for high speed capturing I can see a
number of possible catches.
I would like to see a detailed explanation of how the capabilities
differ from those of v4l2.
(I also doubt that an interface this complex would ever make it into the
kernel.)
-justin
