[ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Mauro Carvalho Chehab]

Hi,

As there are still too things to be discussed in order to improve media
stuff, and most of the developers nowadays are located in Europe and
usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
Germany, on Thrusday/Friday.

There is a perfect opportunity to discuss the media Kernel-Userspace
API improvements that are required for newer devices to work.
So, we hope to have there the major Kernel contributors to the media
subsystem, and some people working on userspace, in order to be sure that
we'll match the needs required on userspace.

In order to properly organize the event, I need the name of the
developers interested on joining us, plus the themes proposed for
discussions.

As usual, we'll be using the media-workshop@linuxtv.org ML for specific
discussions about that, so the ones interested on participate are
requested to subscribe it.

Thanks!
Mauro

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Laurent Pinchart]

Hi Mauro,

On Wednesday 13 August 2014 10:14:11 Mauro Carvalho Chehab wrote:
> Hi,
> 
> As there are still too things to be discussed in order to improve media
> stuff, and most of the developers nowadays are located in Europe and
> usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
> Germany, on Thrusday/Friday.
> 
> There is a perfect opportunity to discuss the media Kernel-Userspace
> API improvements that are required for newer devices to work.
> So, we hope to have there the major Kernel contributors to the media
> subsystem, and some people working on userspace, in order to be sure that
> we'll match the needs required on userspace.
> 
> In order to properly organize the event, I need the name of the
> developers interested on joining us, plus the themes proposed for
> discussions.
> 
> As usual, we'll be using the media-workshop@linuxtv.org ML for specific
> discussions about that, so the ones interested on participate are
> requested to subscribe it.

Thank you for organizing this. I'll be in Düsseldorf the whole week for ELCE 
and LPC, and I will need to attend the IOMMU microconference at LPC on Friday 
the 17th in the afternoon. Apart from that I'm interested and happy to 
participate in the media mini-summit.

Regarding topics, I'm thinking about runtime reconfiguration of pipelines, but 
it's a bit early to tell. I have customer demand for that, but no exact 
schedule yet, so it might be too early.

-- 
Regards,

Laurent Pinchart

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Ricardo Ribalda Delgado]

Hello

I will also be in  Düsseldorf the whole week for ELCE and LPC. I would
love to attend the media mini-summit.

I am interested in multiselection, deadpixels API and multiple
timestamps per buffer.

Thank you very much!

On Thu, Aug 14, 2014 at 1:43 PM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> Hi Mauro,
>
> On Wednesday 13 August 2014 10:14:11 Mauro Carvalho Chehab wrote:
>> Hi,
>>
>> As there are still too things to be discussed in order to improve media
>> stuff, and most of the developers nowadays are located in Europe and
>> usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
>> Germany, on Thrusday/Friday.
>>
>> There is a perfect opportunity to discuss the media Kernel-Userspace
>> API improvements that are required for newer devices to work.
>> So, we hope to have there the major Kernel contributors to the media
>> subsystem, and some people working on userspace, in order to be sure that
>> we'll match the needs required on userspace.
>>
>> In order to properly organize the event, I need the name of the
>> developers interested on joining us, plus the themes proposed for
>> discussions.
>>
>> As usual, we'll be using the media-workshop@linuxtv.org ML for specific
>> discussions about that, so the ones interested on participate are
>> requested to subscribe it.
>
> Thank you for organizing this. I'll be in Düsseldorf the whole week for ELCE
> and LPC, and I will need to attend the IOMMU microconference at LPC on Friday
> the 17th in the afternoon. Apart from that I'm interested and happy to
> participate in the media mini-summit.
>
> Regarding topics, I'm thinking about runtime reconfiguration of pipelines, but
> it's a bit early to tell. I have customer demand for that, but no exact
> schedule yet, so it might be too early.
>
> --
> Regards,
>
> Laurent Pinchart
>
>
> _______________________________________________
> media-workshop mailing list
> media-workshop@linuxtv.org
> http://www.linuxtv.org/cgi-bin/mailman/listinfo/media-workshop



-- 
Ricardo Ribalda

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Laurent Pinchart]

Hi Ricardo,

On Tuesday 19 August 2014 16:48:19 Ricardo Ribalda Delgado wrote:
> Hello
> 
> I will also be in  Düsseldorf the whole week for ELCE and LPC. I would
> love to attend the media mini-summit.
> 
> I am interested in multiselection, deadpixels API and multiple
> timestamps per buffer.

Could you elaborate a bit on that last point ? What kind of timestamps would 
you need, and what are the use cases ?

-- 
Regards,

Laurent Pinchart

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Ricardo Ribalda Delgado]

Hello Laurent

> Could you elaborate a bit on that last point ? What kind of timestamps would
> you need, and what are the use cases ?

Right now we only have one timestamp field on the buffer structure, it
might be a good idea to leave space for some more.

My user case is a camera that is recording a conveyor belt at a very
high frame rate. Instead of tracking the objects on the image with I
use one or more encoders on the belt.  The encoder count  is read on
vsync and kept it on a register(s). When an image is ready, the cpu
starts the dma and read this "belt timestamps" registers.

It would be nice to have an standard way to expose this alternative
timestamps or at least find out if I am the only one with this issue
and/or how you have solve it :)


Best regards!


-- 
Ricardo Ribalda

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Laurent Pinchart]

On Tuesday 19 August 2014 18:29:08 Ricardo Ribalda Delgado wrote:
> Hello Laurent
> 
> > Could you elaborate a bit on that last point ? What kind of timestamps
> > would you need, and what are the use cases ?
> 
> Right now we only have one timestamp field on the buffer structure, it
> might be a good idea to leave space for some more.
> 
> My user case is a camera that is recording a conveyor belt at a very
> high frame rate. Instead of tracking the objects on the image with I
> use one or more encoders on the belt.  The encoder count  is read on
> vsync and kept it on a register(s). When an image is ready, the cpu
> starts the dma and read this "belt timestamps" registers.
> 
> It would be nice to have an standard way to expose this alternative
> timestamps or at least find out if I am the only one with this issue
> and/or how you have solve it :)

I have a similar use cases. UVC transmits a device clock timestamp to the 
host, as well as the corresponding USB SOF counter value. This can be used to 
translate the device clock timestamp to a host timestamp. The uvcvideo driver 
is currently performing that translation in the kernel, but moving it to 
userspace would allow more accurate host timestamp computation by using 
floating-point math.

In a similar fashion CSI2 cameras transmit a 16-bit frame number to the 
receiver. That number is currently expanded to 32-bits by the driver and 
passed to userspace in the v4l2_buffer sequence number. That's fine from a 
kernel point of view, but in userspace the sequence number is lost when using 
the gstreamer v4l2src element.

Have you thought about how you would like to implement those advanced 
timestamps ? Reusing the v4l2_buffer timecode field might be an option, but 
I'm not sure whether it would be the best one. Using a metadata plane also 
comes to mind.

-- 
Regards,

Laurent Pinchart

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Hans Verkuil]

On 08/19/2014 09:00 PM, Laurent Pinchart wrote:
> On Tuesday 19 August 2014 18:29:08 Ricardo Ribalda Delgado wrote:
>> Hello Laurent
>>
>>> Could you elaborate a bit on that last point ? What kind of timestamps
>>> would you need, and what are the use cases ?
>>
>> Right now we only have one timestamp field on the buffer structure, it
>> might be a good idea to leave space for some more.
>>
>> My user case is a camera that is recording a conveyor belt at a very
>> high frame rate. Instead of tracking the objects on the image with I
>> use one or more encoders on the belt.  The encoder count  is read on
>> vsync and kept it on a register(s). When an image is ready, the cpu
>> starts the dma and read this "belt timestamps" registers.
>>
>> It would be nice to have an standard way to expose this alternative
>> timestamps or at least find out if I am the only one with this issue
>> and/or how you have solve it :)
> 
> I have a similar use cases. UVC transmits a device clock timestamp to the 
> host, as well as the corresponding USB SOF counter value. This can be used to 
> translate the device clock timestamp to a host timestamp. The uvcvideo driver 
> is currently performing that translation in the kernel, but moving it to 
> userspace would allow more accurate host timestamp computation by using 
> floating-point math.
> 
> In a similar fashion CSI2 cameras transmit a 16-bit frame number to the 
> receiver. That number is currently expanded to 32-bits by the driver and 
> passed to userspace in the v4l2_buffer sequence number. That's fine from a 
> kernel point of view, but in userspace the sequence number is lost when using 
> the gstreamer v4l2src element.
> 
> Have you thought about how you would like to implement those advanced 
> timestamps ? Reusing the v4l2_buffer timecode field might be an option, but 
> I'm not sure whether it would be the best one. Using a metadata plane also 
> comes to mind.
> 

Just my two cents: I think the timecode field should be reused for this as a
way of storing driver/hardware-specific timestamps. Such timestamps are likely
to be different for different hardware since I do not think that hardware
timestamps can always be converted reliably to the kernel time. They may just
be numbers that software needs to interpret according to what hardware was
used.

M2M devices already copy the timecode field when copying frames (or at least they
should), so changing v4l2_timecode to a union would make sense as that behavior
of m2m devices remains preserved for hardware timestamps.

Regards,

	Hans

Re: [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Guennadi Liakhovetski]

On Wed, 13 Aug 2014, Mauro Carvalho Chehab wrote:

> Hi,
> 
> As there are still too things to be discussed in order to improve media
> stuff, and most of the developers nowadays are located in Europe and
> usually go to ELCE, we're scheduling a two day mini-summit in DÃŒsseldorf,
> Germany, on Thrusday/Friday.
> 
> There is a perfect opportunity to discuss the media Kernel-Userspace
> API improvements that are required for newer devices to work.
> So, we hope to have there the major Kernel contributors to the media
> subsystem, and some people working on userspace, in order to be sure that
> we'll match the needs required on userspace.
> 
> In order to properly organize the event, I need the name of the
> developers interested on joining us, plus the themes proposed for
> discussions.

I'll likely be able to attend too. ATM I'm working on camera support in 
Android. I think Hans discussed related topics at the previous summit in 
the US too, which I didn't manage to attend unfortunately. I'll try to 
double-check results of those discussions and see which topics I'd be 
interested in discussing further.

On a related note, since I live something like 80km from the venue, I was 
thinking about possibly helping to organise a media event in my town - in 
Aachen, or in Düsseldorf itself or in neighbouring Cologne (Köln). Let me 
know if there's interest. We could use Saturday the 18th of October for 
that.

Thanks
Guennadi

> As usual, we'll be using the media-workshop@linuxtv.org ML for specific
> discussions about that, so the ones interested on participate are
> requested to subscribe it.
> 
> Thanks!
> Mauro

Re: [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Philipp Zabel]

Hi Mauro,

Am Mittwoch, den 13.08.2014, 10:14 -0300 schrieb Mauro Carvalho Chehab:
> Hi,
> 
> As there are still too things to be discussed in order to improve media
> stuff, and most of the developers nowadays are located in Europe and
> usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
> Germany, on Thrusday/Friday.
> 
> There is a perfect opportunity to discuss the media Kernel-Userspace
> API improvements that are required for newer devices to work.
> So, we hope to have there the major Kernel contributors to the media
> subsystem, and some people working on userspace, in order to be sure that
> we'll match the needs required on userspace.
> 
> In order to properly organize the event, I need the name of the
> developers interested on joining us, plus the themes proposed for
> discussions.

I'd like to participate in the media mini-summit.
Here are some themes I'd be interested in:

- Helping userspace to use mem2mem devices; clarification of
  encoder/decoder handling, clarification of format/size setting
  in case of dependencies between input and output formats,
  possibly broad categorisation of mem2mem devices (encoder,
  decoder, scaler, rotator, csc/filter, ...)

- Hierarchical media devices - what if you have a lot of media
  entities and some of them are more closely related to each
  other than others.

regards
Philipp

Re: [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Pawel Osciak]

Hi Philipp,

On Fri, Aug 22, 2014 at 10:09 PM, Philipp Zabel <p.zabel@pengutronix.de> wrote:
> - Helping userspace to use mem2mem devices; clarification of
>   encoder/decoder handling, clarification of format/size setting
>   in case of dependencies between input and output formats,
>   possibly broad categorisation of mem2mem devices (encoder,
>   decoder, scaler, rotator, csc/filter, ...)

I'm planning a session on codec API, would like to specify it in
better detail and clear up ambiguities. If you'd have a list of issues
that should be clarified, it would be very useful to add to
discussion.

-- 
Thanks,
Pawel

Re: [media-workshop] [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Ralph Metzler]

Guennadi Liakhovetski writes:
 > I'll likely be able to attend too. ATM I'm working on camera support in 
 > Android. I think Hans discussed related topics at the previous summit in 
 > the US too, which I didn't manage to attend unfortunately. I'll try to 
 > double-check results of those discussions and see which topics I'd be 
 > interested in discussing further.

I'll also try to be there for the mini-summit.
So, if anybody wants to discuss APIs for DVB-T2/C2, CI, modulators,
DVB network streaming or anything else related to DVB drivers ...


 > On a related note, since I live something like 80km from the venue, I was 
 > thinking about possibly helping to organise a media event in my town - in 
 > Aachen, or in Düsseldorf itself or in neighbouring Cologne (Köln). Let me 
 > know if there's interest. We could use Saturday the 18th of October for 
 > that.

I also live just 50km from the venue. 


Regards,
Ralph

Re: [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Philipp Zabel]

Hi,

Am Mittwoch, den 13.08.2014, 10:14 -0300 schrieb Mauro Carvalho Chehab:
> Hi,
> 
> As there are still too things to be discussed in order to improve media
> stuff, and most of the developers nowadays are located in Europe and
> usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
> Germany, on Thrusday/Friday.

Is this a tentative schedule, or is the date set? I.e. can I book a
hotel until Friday now and not worry about having to reschedule?

thanks
Philipp

Re: [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Mauro Carvalho Chehab]

Em Tue, 02 Sep 2014 12:03:34 +0200
Philipp Zabel <p.zabel@pengutronix.de> escreveu:

> Hi,
> 
> Am Mittwoch, den 13.08.2014, 10:14 -0300 schrieb Mauro Carvalho Chehab:
> > Hi,
> > 
> > As there are still too things to be discussed in order to improve media
> > stuff, and most of the developers nowadays are located in Europe and
> > usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
> > Germany, on Thrusday/Friday.
> 
> Is this a tentative schedule, or is the date set? I.e. can I book a
> hotel until Friday now and not worry about having to reschedule?

It is all set.

Regards,
Mauro

Re: [ANNOUNCE] Linux Kernel Media mini-summit on Oct, 16-17 in Düsseldorf, Germany

[Michael Ira Krufky]

Hey all...  It looks like I will be in Dusseldorf that week as well.
:-)  See you next month!

-Mike Ira Krufky

On Tue, Sep 2, 2014 at 8:58 AM, Mauro Carvalho Chehab
<m.chehab@samsung.com> wrote:
> Em Tue, 02 Sep 2014 12:03:34 +0200
> Philipp Zabel <p.zabel@pengutronix.de> escreveu:
>
>> Hi,
>>
>> Am Mittwoch, den 13.08.2014, 10:14 -0300 schrieb Mauro Carvalho Chehab:
>> > Hi,
>> >
>> > As there are still too things to be discussed in order to improve media
>> > stuff, and most of the developers nowadays are located in Europe and
>> > usually go to ELCE, we're scheduling a two day mini-summit in Düsseldorf,
>> > Germany, on Thrusday/Friday.
>>
>> Is this a tentative schedule, or is the date set? I.e. can I book a
>> hotel until Friday now and not worry about having to reschedule?
>
> It is all set.
>
> Regards,
> Mauro
> --
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