v4l interface questions
Hi!
I have few questions about v4l api.
I have device (vicam == usb 3com homeconnect camera), which would like to fit into v4l framework. But... mmap is not really native operation for usb. Should I emulate it, or just return unsupported and expect applications to use read()?
Similar problem is there with formats. vicam has some really strange formats. Should I do conversion in kernel?
Is there some usermode program that can handle camera without mmap ability and can support arbitrary screen sizes + 16bpp grayscale?
Pavel
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I'm [email protected]. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at [email protected]
Quoted 7 lines · Pavel Machek
I have device (vicam == usb 3com homeconnect camera), which would like to fit into v4l framework. But... mmap is not really native operation for usb. Should I emulate it, or just return unsupported and expect applications to use
read()?Similar problem is there with formats. vicam has some really strange formats. Should I do conversion in kernel?
Don't do conversion in the kernel.
Quoted 2 lines
Is there some usermode program that can handle camera without mmap ability and can support arbitrary screen sizes + 16bpp grayscale?
Signature · 3 lines
-Steven In a time of universal deceit, telling the truth is a revolutionary act. -- George Orwell
Quoted 8 lines · Pavel Machek
Hi!
I have few questions about v4l api.
I have device (vicam == usb 3com homeconnect camera), which would like to fit into v4l framework. But... mmap is not really native operation for usb. Should I emulate it, or just return unsupported and expect applications to use
read()?
IHMO applications should be able to fallback to read() if mmap() doesn't work.
Quoted 2 lines
Similar problem is there with formats. vicam has some really strange formats. Should I do conversion in kernel?
Probably. The driver should support at least one of the standard VIDEO_PALETTE_* formats. It is fine to pick one which comes close to the native format of the camera, there is no need to support _all_ formats.
Quoted 2 lines
Is there some usermode program that can handle camera without mmap ability and can support arbitrary screen sizes + 16bpp grayscale?
8bpp grayscale should be no problem with xawtv. I'd suspect you will not find any app which can deal with 16bpp, there isn't even a VIDEO_PALETTE_* #define for this ...
Gerd
Signature · 1 line
Damn lot people confuse usability and eye-candy.