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

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

[Mauro Carvalho Chehab]

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.

Thanks!
Mauro

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

[Hans Verkuil]

Hi Mauro,

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. 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.

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.

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.

Regards,

	Hans

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

[Mauro Carvalho Chehab]

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?

> 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
> 
> _______________________________________________
> media-workshop mailing list
> media-workshop@linuxtv.org
> http://www.linuxtv.org/cgi-bin/mailman/listinfo/media-workshop

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

[Mauro Carvalho Chehab]

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
> > 
> > _______________________________________________
> > media-workshop mailing list
> > media-workshop@linuxtv.org
> > http://www.linuxtv.org/cgi-bin/mailman/listinfo/media-workshop

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

[Hans Verkuil]

On 08/10/2015 03:19 PM, Mauro Carvalho Chehab wrote:
> 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

Looks good. But if you have a sensor, then there should also be a v4l-subdev2
interface for the sensor entity, and it is also controlled by video0, so that
interface-to-entity link is missing.

And the saa7115 output pads need to be renumbered to 4-6 (there are two pads '3'
at the moment and the mixer is linked to the input pad 3).

Regards,

	Hans

> 
>>
>>> 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
>>>
>>> _______________________________________________
>>> media-workshop mailing list
>>> media-workshop@linuxtv.org
>>> http://www.linuxtv.org/cgi-bin/mailman/listinfo/media-workshop
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