Re: [media-workshop] [RFC] Media graph flow for an hybrid device as discussed at the media workshop

[Mauro Carvalho Chehab <mchehab@osg.samsung.com>]

Em Mon, 10 Aug 2015 10:05:24 -0300
Mauro Carvalho Chehab <mchehab@osg.samsung.com> escreveu:

> Em Mon, 10 Aug 2015 14:43:50 +0200
> Hans Verkuil <hverkuil@xs4all.nl> escreveu:
> 
> > Hi Mauro,
> 
> Thanks for the review!
> 
> > 
> > On 08/08/2015 01:33 PM, Mauro Carvalho Chehab wrote:
> > > During the discussions at the Media Workshop, we came with some dot files that
> > > would describe a hybrid PC-consumer TV stick with radio, analog video, analog
> > > TV and digital TV on it.
> > > 
> > > I consolidated all the dot files we've worked there, and added the
> > > connectors for RF, S-Video and Composite.
> > > 
> > > The dot file and the corresponding picture is at:
> > > 	http://linuxtv.org/downloads/presentations/mc_ws_2015/dvb-pipeline-v2.dot
> > > 	http://linuxtv.org/downloads/presentations/mc_ws_2015/dvb-pipeline-v2.png
> > > 
> > > As my plan is to start working on some real driver to produce such graph,
> > > please validate if the entities, interfaces, data links and interface links
> > > are correct, and if the namespace nomenclature is ok, or if I miss something.
> > 
> > This looks OK to me, except for one small detail: I wouldn't use the name
> > "Source entities" for connectors. Instead use "Connector entities" since
> > such entities correspond to actual real connectors on a backplane. 
> 
> Yeah. Well, they're actually "Source connector entities" ;) But I see
> your point. All connectors should be marked with a different type at
> the media_graph_obj.
> 
> > A proper
> > source entity would be a sensor or test pattern generator. Which actually
> > can occur with the em28xx since it's used in webcams as well.
> 
> Ah, true. I'll add that in the graph and use a different color to
> distinguish between "source" and "connector" entities.
> 
> > 
> > And a really, really small detail: in the legend the 'interface link' is an
> > arrow, but it should be a line, since there is no direction. The graph itself
> > is fine.
> 
> Well, I didn't find a way to put a line there. The legend is produced by
> an html code. I would need to have a "line" character, or to add an image.
> 
> Perhaps I should look deeper to find a bold horizontal line at the UTF-8
> charset. &#8212; and &#8213; are too thin. Do you know any char that would
> look better there?

Found one character ;)

I also added a webcam sensor and fixed the legend. See below:

http://linuxtv.org/downloads/presentations/mc_ws_2015/dvb-pipeline-v3.png
http://linuxtv.org/downloads/presentations/mc_ws_2015/dvb-pipeline-v3.dot

> 
> > As you mentioned on irc, the v4l-subdevX nodes won't be created for this device
> > since all the configuration happens via the standard interfaces.
> > 
> > But if they were to be created, then they would appear where they are in this
> > example.
> 
> Thanks!
> Mauro
> 
> > 
> > Regards,
> > 
> > 	Hans
> > 
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