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Re: [pygame] VideoCapture, PIL, and PyGame



Why not just reverse the string in order to do the BGR->RGB
conversion? This will also vertically and horizontally flip it, so
you'll just need to horizontally flip it.

On Sun, Jun 14, 2009 at 2:25 AM, René Dudfield<renesd@xxxxxxxxx> wrote:
> hi,
>
> take a look at svn pygame.  There is an implementation of
> pygame.camera which uses the VideoCapture module.
>
> cheers,
>
>
>
> On Sun, Jun 14, 2009 at 2:35 PM, Ian Mallett<geometrian@xxxxxxxxx> wrote:
>> Hi,
>>
>> So, I'm trying to get VideoCapture working with PyGame.  I've modified the
>> standard VideoCapture.py file to make it simpler and easier to read.  I've
>> attached it as well as my program, main.py.
>>
>> VideoCapture.py defines a class Device.  Device has two functions that I'm
>> concerned with: .getBuffer(), which returns (string_data,width,height), and
>> .getImage(), which returns a PIL image made with .getBuffer().
>>
>> I'm trying to get a PyGame surface from all this.  Every code sample I've
>> seen converts the PIL image (returned from .getImage()) back into a string,
>> and then makes a PyGame image with pygame.image.frombuffer(...):
>> im = Camera.getImage()
>> image = pygame.image.frombuffer(im.tostring(), im.size, im.mode)
>>
>> Though this works nicely, it seems terribly inefficient--VideoCapture.py
>> takes the data as a string from .getBuffer(), and makes a PIL image.  The
>> main, main.py, must then change this PIL image back into a string again, and
>> then make a PyGame surface from that.  (Basically:
>> STRING->PIL->STRING->PYGAME).  This setup doesn't fly realtime.  Moreover,
>> it requires an extra dependency, PIL.
>>
>> So, I tried just converting the original string from .getBuffer() directly
>> into a PyGame surface.  (Basically: STRING->PYGAME):
>> data = Camera.getBuffer()
>> image = pygame.image.frombuffer(data[0],(data[1],data[2]),"RGB")
>>
>> But this has problems.  It doesn't crash, but the image is upsidedown and
>> the red and blue color channels appear to be flopped.  I tried fixing it
>> with surfarray, which didn't work.  Then I tried finding what was wrong, and
>> got inconsistent results.
>>
>> How can I get the second method (method 2: STRING->PYGAME) to look like the
>> first method (method 1: STRING->PIL->STRING->PYGAME)?  main.py lets you
>> switch back and forth (press 1 for method 1, 2 for method 2).
>>
>> Ian
>>
>