Linux capture application

jamesf

As some people will already be aware, I've been spending some of my evenings working on a Linux capture application for two or three weeks. Having first got it to work with V4L2-based cameras (I started there because I'm reasonably familiar with the V4L2 interface having hacked on a few of the drivers once in a while) this weekend I turned my attention to support for the ASI cameras.

I still have some work to do on this, but this evening I managed to get my first images out of the camera and displayed in the capture application:

(I guess it's now clear why I've been asking so many questions about the SDK in the last couple of days

Once I've sorted out ROI selection and some issues I'm having with exposure times and added a histogram display then I think it should be usable for imaging, even if significantly incomplete.

The application itself is written using the Qt toolkit, so potentially could port to Windows or the Mac, but my specific goal is to have a single usable capture application for Linux that works with all the different camera models I have.

James

stuw

Looking forward to trying this out James. I tried doing a capture prog, but my C++ experience was lacking. Will you be releasing the source to this?

jamesf

I will be releasing the source. I've earned a fair living working with open source for quite a number of years now and I'm very happy to have the opportunity to contribute back to the community.

I need to work out how to package it all up because it's a moderately complex build combining my own build of the ffmpeg library to write AVI files (some of the ffmpeg versions, even in recent well-recognised Linux distributions don't have sufficient support to write AVI files with Linux) and binary-only pieces such as the ASI library, the Qt components (which have their own build system) in C++ and my camera API code which is all in C. If that looks like it's going to take more than a couple of days then I'll probably make the binary available for anyone who wants to use it.

I'd also like to put together .deb and .rpm versions of the binaries for those people who don't want to build from source, but that definitely will take a while. It's been some years since I did any work on building RPMS and I've never tried to build a .deb before. At least I should be able to do all of that work on virtual machines these days :)

James

Sam@ZWO

Wow! that's really great news for those who use linux system.

Thank you James!

jamesf

Thanks to Sam's help today I believe I now have the ASI120MC properly working, except for handling binning.

I have a 120MM so I shall get that working as well, but I don't have any of the other cameras so I'll just have to hope they work until someone else can test them.

James

jamesf

I now have support for the ASI120MM pretty much done

There are just a few things that I have left on my list of things to do for these cameras:

1. Support for binning

2. 12-bit support

3. raw undebayered video support

I don't know if the current Linux SDK supports 12 bit at all, but that should be easy to test by requesting 16-bit raw video and checking to see if I still only get 8-bit values back.

I also don't know if it is possible to get raw colour video from the camera. The fact that it is possible to request the matrix pattern from the driver suggests that it is -- why else would you need to know it? I can't find any information about how to do it though. Perhaps just requesting 8-bit RAW from a colour camera?

If neither of these are possible then it becomes a very short list to get done :)

James

Sam@ZWO

Hi James

the ASI120MC color module support 4 types image output.

IMG_RAW8 mono data 8bit per pixel

IMG_RGB24 RGB data

IMG_RAW16 mono data 16bit per pixel

IMG_Y8: debayed data and greyed

you can call isImgTypeSupported to check if its supported by current module

jamesf

Thank you for that, Sam. I shall give it a try later.

James

jamesf

In 16-bit mode, is the data stored big-endian or little-endian?

James

jamesf

Actually, is 16-bit (or 12-bit) mode supported at all by the SDK for the ASI120MM? If I try setting it I just seem to get a black (or very dark) frame.

James

Sam@ZWO

here is the version fix the 16bit problem

http://www.zwoptical.com/software/asicamera%20linux%20sdk%200914.zip

jamesf

That certainly means I can now see an image. I suspect the data is big-endian and I have assumed little-endian, but I can work on sorting that out.

James

jamesf

I had it the other way around. I had assumed the 16-bit data was big-endian, but it looks as though it is actually little-endian.

Can you confirm that is correct, Sam?

Thanks,

James

Sam@ZWO

The 16bit data is LITTLE-ENDIAN

jamesf

Excellent. Thank you for confirming that.

James