[gst-devel] Advice on plugin/pipeline design

[Sameer Naik]

Hello,
I had taken a look at the gstreamer-ti plugins some time back. One of the
things that i noticed is threads being spawned from within the decoder
plugins, which does not fit well with me. I also noticed quite a lot of bugs
in the code, which kept me from using it or hacking on it. Besides i already
have most of the functionality implemented and just need to tweak my
code/design a bit, hence the mail.

Thanks and Regards
~Sameer

On Sun, Nov 22, 2009 at 9:27 PM, Brijesh Singh <brijesh.ksingh at gmail.com>wrote:

> Hello,
>
> Have you looked at gstreamer.ti.com ?  gst_ti has all the elements you
> need. It support wide varity of TI platforms. (DM6446, DM355, DM365,
> DM357, DM6467, OMAP3530 and more...).
>
> To understand design detail you can watch 25-min of video presentation.
>
>
> https://gstreamer.ti.com/gf/project/gstreamer_ti/wiki/?pagename=OverviewPresentation
>
> We do not have pad-allocation method yet (may be you can contribute on
> project). We use hw accelerated framecopy to copy the data from video
> decoder -> sink element. Depending on the platform, this hw
> accelerator may be resizer/dma/vdce/sdma etc...
>
>
> Thanks
> Brijesh
>
> On Sun, Nov 22, 2009 at 4:18 AM, Sameer Naik
> <sameer.subscriptions at damagehead.com> wrote:
> > Hi,
> > I am developing a multimedia application for an embedded system based on
> > TI's DM6446 platform. The decoding of the audio and video frames will be
> > done using the HW decoders. The platform also includes a hardware
> resizer,
> > that allows resizing of the video frames in hardware, thereby making the
> > resizing operations pretty quick.
> >
> > I need some advice on the architecture that i should base by application
> on.
> > Following are the architectures that i have come up with
> >
> > 1.
> > - audio decoder plugins
> > - video decoder plugins
> > - resizer plugin
> > - frame buffer output plugin
> > Here i can build a seperate plugin to do the resizing of video frames.
> This
> > would conform more with gstreamer's idea that "every element does one
> > thing", providing better reusability. To reduce to number of memcpy's, i
> > could equip the frame buffer plugin with pad allocation capabilities and
> > accordingly add pad_alloc calls in the resizer plugin. The only this is,
> in
> > this case the frames will always be resized, regardless of whether the
> frame
> > is going to be displayed or dropped. I am not really sure whether this is
> > that big of a problem considering that the number of frames that could be
> > dropped is very less.
> >
> > 2.
> > - audio decoder plugins
> > - video decoder plugins
> > - frame buffer plugin with resizing capabilities using the hw resizer.
> > Here i can build the frame buffer plugin with the built in capability to
> > resize video frames. In this case i could resize the frame only if it is
> > going to be displayed (i.e. just before it would be displayed on screen).
> > Now in this case i loose the reusability advantage, which i can live with
> if
> > i am able to achieve smooth video playback with av sync. In this case, I
> am
> > not sure whether the last minute resizing of the frame would introduce a
> lot
> > of latency while displaying the frame. Given that it is a hardware
> resizer i
> > am assuming it would be quick.
> >
> > P.S. I would be employing the pad allocation method in other parts of the
> > pipeline as well, so as to reduce the number of memcpy's going on in the
> > pipeline.
> >
> > Please Advice.
> >
> > Regards
> > ~Sameer
> >
> >
> >
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>
>
>
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>
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