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Re: [pygame] BUG: JPEG colors saving a pygame.camera surface
I'm not sure what it would be without seeing the error output, but
there is a way around that. camera.list_cameras() will return a list
of the cameras plugged into the computer. If the list is empty, you
know it found no cameras. You could use it as follows:
camlist = camera.list_cameras()
if len(cameras) > 0:
cam = camera.Camera(camlist[0])
Nirav
On Mon, Apr 20, 2009 at 9:46 AM, Alexandre Quessy <alexandre@xxxxxxxxxx> wrote:
> 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/
>