v4l2-ctl-streaming: ideas for improvements

v4l2-ctl-streaming: ideas for improvements

[Hans Verkuil]

Hi all,

Just in case someone has time to work on this: I thought I'd write down some
of the ideas I have to improve the streaming code in v4l2-ctl:

1) Add an option to select between limited and full range colors.

2) Add more test patterns:
	- solid colors: black, white, red, green, blue, cyan, yellow, magenta.
	- grey 'color' bar
	- grey ramp
	- a pattern containing SAV and EAV codes in each plane (perhaps this
	  should be a separate option, 'overlaying' those codes): this is a very
	  nasty test case that can be used to test proper handling of such codes
	  in an image.
	- moving patterns
	- horizontal colorbars
	- thin lines: horizontal, vertical, both.
	- random contents

3) For the capture side add pattern validation: check that the contents you
   captured matches the given pattern. Very useful for testing.

4) Add support for capturing/displaying frames with different sizes (e.g.
   compressed streams). Currently the output just appends all planes/frames
   together without writing the plane/frame sizes anywhere. The input assumes
   fixed sized planes/frames. We probably need to add a meta file that contains
   the 'bytesused' values. Perhaps that file should also contain format
   information that can be used later.

5) Add some support to give keyboard commands when streaming. E.g. 'q' to stop
   streaming gracefully (and so also ensure that all the data is written to file,
   something that doesn't happen with ctrl-c).

   Other commands for the future are encoder/decoder commands such as speeding up
   or down.

6) MPEG encoders can generate an index file (VIDIOC_G_ENC_INDEX). Add an option to
   generate that and to use it when decoding. I actually have some old test
   application that does just that, and that also has encoder/decoder command
   support (see item 5 above): http://ivtvdriver.org/svn/ivtvtv

7) Add VBI streaming support. Split off the VBI code from qv4l2 into a library
   and use that in v4l2-ctl to slice the raw VBI and to interpret the data. That
   should replace the vbi-test.c, sliced-vbi-detect.c and sliced-vbi-test.c
   utilities in contrib.

Regards,

	Hans

Re: v4l2-ctl-streaming: ideas for improvements

[Laurent Pinchart]

On Wednesday 10 April 2013 09:27:07 Hans Verkuil wrote:
> Hi all,
> 
> Just in case someone has time to work on this: I thought I'd write down some
> of the ideas I have to improve the streaming code in v4l2-ctl:
> 
> 1) Add an option to select between limited and full range colors.
> 
> 2) Add more test patterns:
> 	- solid colors: black, white, red, green, blue, cyan, yellow, magenta.
> 	- grey 'color' bar
> 	- grey ramp
> 	- a pattern containing SAV and EAV codes in each plane (perhaps this
> 	  should be a separate option, 'overlaying' those codes): this is a very
> 	  nasty test case that can be used to test proper handling of such codes
> 	  in an image.
> 	- moving patterns
> 	- horizontal colorbars
> 	- thin lines: horizontal, vertical, both.
> 	- random contents

I've implemented support for generating test patterns in both my fbdev-test 
program (http://git.ideasonboard.org/fbdev-test.git) and in the libdrm 
modetest program. Maybe we should consider splitting that to a shared library.

> 3) For the capture side add pattern validation: check that the contents you
>    captured matches the given pattern. Very useful for testing.
> 
> 4) Add support for capturing/displaying frames with different sizes (e.g.
>    compressed streams). Currently the output just appends all planes/frames
>    together without writing the plane/frame sizes anywhere. The input
> assumes fixed sized planes/frames. We probably need to add a meta file that
> contains the 'bytesused' values. Perhaps that file should also contain
> format information that can be used later.
> 
> 5) Add some support to give keyboard commands when streaming. E.g. 'q' to
> stop streaming gracefully (and so also ensure that all the data is written
> to file, something that doesn't happen with ctrl-c).
> 
>    Other commands for the future are encoder/decoder commands such as
> speeding up or down.
> 
> 6) MPEG encoders can generate an index file (VIDIOC_G_ENC_INDEX). Add an
> option to generate that and to use it when decoding. I actually have some
> old test application that does just that, and that also has encoder/decoder
> command support (see item 5 above): http://ivtvdriver.org/svn/ivtvtv
> 
> 7) Add VBI streaming support. Split off the VBI code from qv4l2 into a
> library and use that in v4l2-ctl to slice the raw VBI and to interpret the
> data. That should replace the vbi-test.c, sliced-vbi-detect.c and
> sliced-vbi-test.c utilities in contrib.

-- 
Regards,

Laurent Pinchart

Re: v4l2-ctl-streaming: ideas for improvements

[Hans Verkuil]

On Fri April 12 2013 11:31:36 Laurent Pinchart wrote:
> On Wednesday 10 April 2013 09:27:07 Hans Verkuil wrote:
> > Hi all,
> > 
> > Just in case someone has time to work on this: I thought I'd write down some
> > of the ideas I have to improve the streaming code in v4l2-ctl:
> > 
> > 1) Add an option to select between limited and full range colors.
> > 
> > 2) Add more test patterns:
> > 	- solid colors: black, white, red, green, blue, cyan, yellow, magenta.
> > 	- grey 'color' bar
> > 	- grey ramp
> > 	- a pattern containing SAV and EAV codes in each plane (perhaps this
> > 	  should be a separate option, 'overlaying' those codes): this is a very
> > 	  nasty test case that can be used to test proper handling of such codes
> > 	  in an image.
> > 	- moving patterns
> > 	- horizontal colorbars
> > 	- thin lines: horizontal, vertical, both.
> > 	- random contents
> 
> I've implemented support for generating test patterns in both my fbdev-test 
> program (http://git.ideasonboard.org/fbdev-test.git) and in the libdrm 
> modetest program. Maybe we should consider splitting that to a shared library.

Good to know.

One idea I have is to split off test pattern generation from vivi into its own
source and sync that with v4l-utils ('make sync-with-kernel'). Having both vivi
and a v4l-utils test-pattern library support the same patterns/formats would
be beneficial in my opinion.

Regards,

	Hans

> 
> > 3) For the capture side add pattern validation: check that the contents you
> >    captured matches the given pattern. Very useful for testing.
> > 
> > 4) Add support for capturing/displaying frames with different sizes (e.g.
> >    compressed streams). Currently the output just appends all planes/frames
> >    together without writing the plane/frame sizes anywhere. The input
> > assumes fixed sized planes/frames. We probably need to add a meta file that
> > contains the 'bytesused' values. Perhaps that file should also contain
> > format information that can be used later.
> > 
> > 5) Add some support to give keyboard commands when streaming. E.g. 'q' to
> > stop streaming gracefully (and so also ensure that all the data is written
> > to file, something that doesn't happen with ctrl-c).
> > 
> >    Other commands for the future are encoder/decoder commands such as
> > speeding up or down.
> > 
> > 6) MPEG encoders can generate an index file (VIDIOC_G_ENC_INDEX). Add an
> > option to generate that and to use it when decoding. I actually have some
> > old test application that does just that, and that also has encoder/decoder
> > command support (see item 5 above): http://ivtvdriver.org/svn/ivtvtv
> > 
> > 7) Add VBI streaming support. Split off the VBI code from qv4l2 into a
> > library and use that in v4l2-ctl to slice the raw VBI and to interpret the
> > data. That should replace the vbi-test.c, sliced-vbi-detect.c and
> > sliced-vbi-test.c utilities in contrib.
> 
>