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Re: [pygame] BUG: JPEG colors saving a pygame.camera surface

Hello René,
We save frames in lists. You can take a frame either by pressing space
bar, or using an intervalometer. (for timelapses) The right region of
the display shows the resulting animation in a loop. (for now) The
left region shows the current video input, plus an optional onion skin
of the last recorded frame. A screen shot will be online soon.

By the way, there is an other bug. With V4L2, if there is no camera
plugged-in, sometimes, I get a null pointer error and it says "Pygame
parachute", or something. And then it crashes. I have heard it's v4l2
that is a bit flaky, but that some higher-level wrapper, such as
Gstreamer, make sure things don't crash when using v4l2. Of course,
bugs are not reproducable when you need them.... (so that I could
copy-paste the output here)

a



2009/4/19 René Dudfield <renesd@xxxxxxxxx>:
> looks pretty cool :)
>
> How does it work?
>
> I imagine you can take snapshots, and then do playbacks?  Or can you do a
> video recording too?  So in video mode, it'd take snapshots at a given frame
> rate.
>
> Are there any screen shots?
>
>
>
>
> On Sat, Apr 18, 2009 at 12:54 PM, Alexandre Quessy <alexandre@xxxxxxxxxx>
> wrote:
>>
>> Problem solved !!
>> Thanks a lot Nirav.
>>
>> If you want to try toonloop, you can checkout the code and run it.
>> The installation instructions for Ubuntu are in here :
>> http://code.google.com/p/toonloop/source/browse/trunk/doc/INSTALL.txt
>>
>> Try ./toonloop.py --help for startup flags, and press "h" while it is
>> running for instructions.
>> It needs a valid pygame camera, of course.
>> See http://toonloop.com for more informations.
>> We need beta testers too. And I think this is a wonderful application
>> of pygame.camera.
>>
>> a
>>
>> 2009/4/17 Nirav Patel <olpc@xxxxxxxxxxxxxx>:
>> > Also, forgot to mention this, but thanks for using the camera module!
>> > It has yet to experience widespread use, so this kind of beta testing
>> > is great to get it ready for the next pygame release.
>> >
>> > Nirav
>> >
>> > On Fri, Apr 17, 2009 at 11:17 AM, Nirav Patel <olpc@xxxxxxxxxxxxxx>
>> > wrote:
>> >> Ah yes, this seems to be a bug in both JPEG saving and in the camera
>> >> module.  Fun stuff.
>> >>
>> >> The JPEG assumes that any 24 bit surface is going to be in the exact
>> >> color order that it expects.  Which is fine, except that the default
>> >> color order for a 24 bit Surface is not that.
>> >>
>> >> This also led me to find a bug in the camera module though, where if
>> >> you are using a 24 bit surface, it will assume you want the default
>> >> color order, regardless of if you hand it a Surface to use that has a
>> >> different color order.
>> >>
>> >> I commited the one line fix for JPEG, which just does an additional
>> >> check to see if it needs to create a new surface or not.  Please test
>> >> it if you can.  The fix for the camera module may take longer, as I
>> >> need to rethink some assumptions, though in the vast majority of use
>> >> cases, users should not be effected.
>> >>
>> >> Nirav
>> >>
>> >> On Fri, Apr 17, 2009 at 9:48 AM, René Dudfield <renesd@xxxxxxxxx>
>> >> wrote:
>> >>> Hi,
>> >>>
>> >>> can you please let me know the result of:
>> >>>
>> >>> cam_surf = X
>> >>> normal_surf = pygame.Surface((1,1))
>> >>> surfs = cam_surf, normal_surf
>> >>>
>> >>> for s in surfs:
>> >>>     print s.get_losses(), s.get_masks(), s.get_shifts()
>> >>>
>> >>> I think maybe the jpeg saving code isn't respecting one of those.
>> >>> Actually... don't worry, I'm pretty sure that's the cause of it.
>> >>> Will fix
>> >>> soon.
>> >>>
>> >>> cheers,
>> >>>
>> >>>
>> >>>
>> >>> On Fri, Apr 17, 2009 at 11:14 PM, Alexandre Quessy
>> >>> <alexandre@xxxxxxxxxx>
>> >>> wrote:
>> >>>>
>> >>>> Hello Pygame people,
>> >>>> This is my first post on this list, and more might follow since I am
>> >>>> using pygame for ToonLoop, a stop motion software. The new
>> >>>> pygame.camera module works for me and this is very good job. Thanks
>> >>>> for contributing that !
>> >>>>
>> >>>> I think I found a bug ! Hopefully it is only my code that is wrong
>> >>>> and
>> >>>> this is easy to fix.
>> >>>>
>> >>>> When I save a Pygame surface that I obtained using pygame.camera to a
>> >>>> JPEG using pygame.image.save, the colors are messed up. It looks like
>> >>>> the red and blue channels are interchanged. Thus, maybe my surface is
>> >>>> RBG, whereas pygame.image expects RGB. A camera image doesn't contain
>> >>>> any alpha channel usually.
>> >>>>
>> >>>> When I display the surface as a pygame sprite the colors are OK.
>> >>>> When I display the surface as an OpenGL texture the colors are OK.
>> >>>> (using tostring(surface, "RGBX", True))
>> >>>> When I save the surface as an other format such as PNG or BMP the
>> >>>> colors
>> >>>> are OK.
>> >>>> When I use a surface obtained by loading a JPG image, the colors are
>> >>>> OK.
>> >>>> The bug only occurs when I save a surface obtained using the
>> >>>> pygame.camera module.
>> >>>> It consistently happened on 3 Linux computers.
>> >>>>
>> >>>> I use Pygame compiled from today's SVN with Python 2.5.2 on Ubuntu
>> >>>> GNU/Linux 8.10 using a V4L2 device. (a WinTV card)
>> >>>>
>> >>>> A short code snippet to reproduce the bug:
>> >>>> http://rafb.net/p/gccaJG37.html
>> >>>>
>> >>>> A JPEG to see how the output looks like :
>> >>>> http://toonloop.com/static/tmp/image_color_test_out.jpg
>> >>>> A correct image in an other format to compare :
>> >>>> http://toonloop.com/static/tmp/image_color_test_out.png
>> >>>>
>> >>>> If you want to download the code and the test image I use :
>> >>>> http://toonloop.com/static/tmp/bug_color_jpeg.tar.gz
>> >>>> I also convert the colorbars.jpg files to surface and back to a JPG
>> >>>> file for comparison. It works flawlessly.
>> >>>>
>> >>>> --
>> >>>> Alexandre Quessy
>> >>>> http://alexandre.quessy.net/
>> >>>
>> >>>
>> >>
>> >
>>
>>
>>
>> --
>> Alexandre Quessy
>> http://alexandre.quessy.net/
>
>



-- 
Alexandre Quessy
http://alexandre.quessy.net/