[vlc-devel] Re: input callback
Sigmund Augdal Helberg
sigmund.augdal at gmail.com
Thu Jan 19 13:32:54 CET 2006
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
> >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
> >Hope this helps (and works).
> >>Antoine Cellerier
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