[vlc-devel] Re: input callback

[Vaclav Koldus]

Sigmund Augdal Helberg napsal(a):

>On Thu, 2006-01-19 at 13:03 +0100, Vaclav Koldus wrote:
>  
>
>>Sigmund Augdal Helberg napsal(a):
>>
>>    
>>
>>>On Wed, 2006-01-18 at 16:05 +0100, Antoine Cellerier wrote:
>>> 
>>>
>>>      
>>>
>>>>On Wed, Jan 18, 2006, Vaclav Koldus wrote:
>>>>   
>>>>
>>>>        
>>>>
>>>>>That's why I would rather add a callback to input. Now this would work 
>>>>>fine, but
>>>>>in future I want to use VLM. Is there any possibility??
>>>>>     
>>>>>
>>>>>          
>>>>>
>>>>The issue is that you can't really add a callback to input since it is
>>>>killed and respawned when a new one is needed. (Someone correct me if
>>>>i'm wrong)
>>>>
>>>>And i don't know about any similar callback variable that the vlm
>>>>media element might update when changing the input it's using. (That
>>>>wouldn't be too hard to add i guess)
>>>>   
>>>>
>>>>        
>>>>
>>>You could probably grab a hold on the input (using vlc_object_find) and
>>>then query it's b_die at regular intervals. And then trigger a name
>>>renewal at this time. make sure you call vlc_object_release once b_die
>>>is set, otherwise you'll get nasty errors. 
>>>
>>>After the current input has died there could probably be a while when
>>>there is no input before a new one is spawned, you should handle this
>>>case.
>>>
>>>Btw, what kind of module are you working on? If it is (as you say) a
>>>child of the input, then the module will very likely be killed as well
>>>when the input is.
>>>
>>> 
>>>
>>>      
>>>
>>Well, I don't know VLC object strucure well enough to say it is/isn't 
>>child of the input. I've just tried to find parent and it worked.
>>In fact I'm writing video filter module. It renders various videotext 
>>informations on the screen. I wanted it to depend on
>>the filename (to decide whether show some info.) At this rate I use 
>>playlist so callback on playlist is OK now.
>>Anyway video filter isn't killed with input as I've found out.
>>
>>In future I want to use VLM to achieve better timing of played files and 
>>use the mosaic principle to show multiple videos
>>in one output (PIP etc.) Because there are special requirements on this 
>>filter I decided not to use VLC built in
>>features and write my own. I've got my own YUV rendering library using 
>>freetype to render text and simply
>>draws images in native YUV. Screen templates are defined in XML files 
>>and now I'm working on scheduling them
>>by mysql based queue. I will need to solve another problem here, cause I 
>>can't simply use the filename for
>>decisions when there are multiple source files. I haven't thought over 
>>this yet so there's probably no point in bothering
>>with VLM sources now.
>>
>>Only original VLC filter I took advantage of is blending filter. Here 
>>I've got a question. I don't understand
>>the blending filter code a bit so I don't know. Is there any chance to 
>>improve performance of blending
>>by rewriting it in sse2 or mmx? I already had some performance issues 
>>with my filter. I optimized
>>colorspace conversions (in DV decoding/encoding, another part of my 
>>project) by sse2 which was
>>enough for now but what when the requirements raises again?
>>I think blending is a good candidate for optimalization. Or am I wrong?
>>    
>>
>Me too. I looked partially into this once, but never got around to write
>any code. basically you need to grab some bytes and convert these into
>16bit words. Do multiplication and addition and then convert back into
>bytes.
>
>Regards
>
>Sigmund
>  
>
SSE2 can do this. But only on some video sizes ( divisible by 4/8/16 
depending on data type ).
Seems blending module calls different functions for different formats so 
I think I could rewrite some of them
in sse2. I'll think about it more...

V.

>>Thanks
>>
>>V.
>>
>>    
>>
>>>Hope this helps (and works).
>>>
>>>Sigmund
>>> 
>>>
>>>      
>>>
>>>>-- 
>>>>Antoine Cellerier
>>>>dionoea
>>>>
>>>>   
>>>>
>>>>        
>>>>
>>> 
>>>
>>>      
>>>
>
>  
>

-- 
This is the vlc-devel mailing-list, see http://www.videolan.org/vlc/
To unsubscribe, please read http://developers.videolan.org/lists.html