[gst-devel] Advice on plugin/pipeline design

[Sameer Naik]

Sure

On Sun, Nov 22, 2009 at 11:43 PM, Brijesh Singh <brijesh.ksingh at gmail.com>wrote:

> >One of the things that i noticed is threads being spawned from within the
> decoder
> >plugins, which does not fit well with me.
>
> Well threads are used for parallelizing  ARM and DSP execution to meet
> the real-time performance on some platforms. But you can remove thread
> and call decoder directly from the chain() functions. Or use queue
> element to put the decoder element in different threads.
>
> > I also noticed quite a lot of bugs in the code, which kept me from using
> it or hacking on it.
> Can you please submit BUGs on gstreamer.ti.com ?
>
>
> Thanks
> Brijesh
>
> On Sun, Nov 22, 2009 at 11:07 AM, Sameer Naik
> <sameer.subscriptions at damagehead.com> wrote:
> > 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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> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Confusion is always the most honest response.
> >>
> >>
> >>
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>
>
>
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>
>
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