[Kdenlive-devel] [Mlt-devel] Qt based text producer

[Marco Gittler]

after changing a lot, the copy of image/alpha works now.
(QApplication cannot be run vom ...init (), else nothing will be seen  
in the buffer anymore, when overlaying)

the read/draw code is copied from kdenlive.
if i set manualy the alpha value to 255, it works like expected.
let QGraphicsScene render the scene, will result in very low alpha  
values (nearly nothing to see,
in contrast to the same routine in kdenlive, which shows the colors )

so the rest is now a Qt-based thing.

maybe a second tester may give some remarks to this.

regards marco

Am 14.07.2009 um 23:24 schrieb Dan Dennedy:

> 2009/7/14 Marco Gittler <g.marco at freenet.de>:
>>
>> Am 12.07.2009 um 22:39 schrieb Dan Dennedy:
>>
>>> 2009/7/11 Marco Gittler <g.marco at freenet.de>:
>>>>
>>>> Am 10.07.2009 um 23:53 schrieb Dan Dennedy:
>>>>
>>>>> 2009/7/10 Marco Gittler <g.marco at freenet.de>:
>>>>>>
>>>>>> @dan th title should be created with alpha channel.
>>>>>> how can i test in melt  to overlay this title over a video ?
>>>>>
>>>>> Please make sure that your new producer only produces  
>>>>> mlt_image_rgb24a
>>>>> and indicates it. Do not worry about conversion to  
>>>>> mlt_image_yuv422
>>>>> anymore.
>>>>>
>>>>>> melt kdenlivetitle:try.kdenlivetitle -track video.avi -attach
>>>>>> transition:mix
>>>>>> -> does not work :(
>>>>>
>>>>> add "*.kdenlivetitle=kdenlivetitle" to core/loader.dict
>>>>>
>>>>> melt video.avi -filter watermark:try.kdenlivetitle
>>>>> composite.progressive=1
>>>>
>>>> nice, this works for pixbuf pictures. but with the  
>>>> kdenlivetitle :no
>>>> overlay
>>>> as standalone prodcuer the titleplayer works very well.
>>>>
>>>> does mlt_image_rgb24a, also include (like the name seems to say)  
>>>> the
>>>> alpha
>>>> channel ?
>>>
>>> Yes.
>>>
>>>> it seems the alpha will not be set.
>>>
>>> If you return mlt_image_rgb24a and do not include the alpha channel
>>> byte per pixel, then the image will skewed because downstream
>>> functions expect 4 bytes per pixel. Producer qimage supports this,  
>>> but
>>> it must convert ARGB to RGBA. Maybe something in the way you  
>>> render is
>>> writing alpha channel byte as 0xff.
>>
>> the image created i now rgb24a and includes real alpha data.
>> playing the kdenlivetitle alone plays correct.
>> but as overlay (watermark) with other producers will not show  
>> anything.
>>
>> tested with producer_qimage (works in both cases).
>> any idea what can go wrong ? (the producer_get_image is not large,  
>> but i
>> can't see any error )
>
> Try this. Do not allocate QImage using the existing buffer. Let it
> create its own and return that from Title::drawKdenliveTitle. Then,
> copy from QImage to the MLT image buffer the same way that
> qimage_wrapper.cpp does - using qRed()..qAlpha().
>
> -- 
> +-DRD-+
>
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