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From: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: linux-media@vger.kernel.org, Sakari Ailus <sakari.ailus@iki.fi>,
	Hans Verkuil <hverkuil@xs4all.nl>,
	remi@remlab.net, Kamil Debski <k.debski@samsung.com>
Subject: Re: [RFC] Timestamps and V4L2
Date: Thu, 27 Sep 2012 00:30:49 +0200	[thread overview]
Message-ID: <50638219.7020105@gmail.com> (raw)
In-Reply-To: <32114057.tIVjSTYujk@avalon>

Hi Laurent,

On 09/25/2012 02:35 AM, Laurent Pinchart wrote:
> Does the clock type need to be selectable for mem-to-mem devices ? Do device-
> specific timestamps make sense there ?

I'd like to clarify one thing here, i.e. if we select device-specific
timestamps how should the v4l2_buffer::timestamp field behave ?

Are these two things exclusive ? Or should v4l2_buffer::timestamp be 
valid even if device-specific timestamps are enabled ?

With regards to your question, I think device-specific timestamps make
sense for mem-to-mem devices. Maybe not for the very simple ones, that
process buffers 1-to-1, but codecs may need it. I was told the Exynos/
S5P Multi Format Codec device has some register the timestamps could
be read from, but it's currently not used by the s5p-mfc driver. Kamil
might provide more details on that.

I guess if capture and output devices can have their timestamping clocks
selectable it should be also possible for mem-to-mem devices.

--

Regards,
Sylwester

  parent reply	other threads:[~2012-09-26 22:30 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-20 20:21 [RFC] Timestamps and V4L2 Sakari Ailus
2012-09-20 21:08 ` Rémi Denis-Courmont
2012-09-21  8:47 ` Christian Gmeiner
2012-09-21  9:33 ` Hans Verkuil
2012-09-22 12:38   ` Sakari Ailus
2012-09-22 17:12     ` Sylwester Nawrocki
2012-09-22 20:28       ` Daniel Glöckner
2012-09-23 18:40         ` Sylwester Nawrocki
2012-09-25  0:35           ` Laurent Pinchart
     [not found]             ` <5061DAE3.2080808@samsung.com>
2012-09-25 17:17               ` Kamil Debski
2012-09-26 22:30             ` Sylwester Nawrocki [this message]
2012-09-27 10:41               ` Laurent Pinchart
2012-09-23 11:43       ` Sakari Ailus
2012-09-24 20:11         ` Rémi Denis-Courmont
2012-09-25  6:50           ` Hans Verkuil
2012-09-25  0:34       ` Laurent Pinchart
2012-09-25 22:48         ` Sylwester Nawrocki
2012-09-23  9:18     ` Hans Verkuil
2012-09-23 13:07       ` Sakari Ailus
2012-09-24  8:30         ` Hans Verkuil
2012-09-25  0:21       ` Laurent Pinchart
2012-09-24 23:42   ` Laurent Pinchart
2012-09-25  0:00   ` Laurent Pinchart
2012-09-25  6:47     ` Hans Verkuil
2012-09-25 10:48       ` Laurent Pinchart
2012-09-25 10:54         ` Hans Verkuil
2012-09-25 11:09           ` Laurent Pinchart
2012-09-25 20:12           ` Sakari Ailus
2012-09-26  9:13             ` Laurent Pinchart
2012-09-26 19:17               ` Sakari Ailus
2012-09-27 10:55                 ` Laurent Pinchart
2012-09-25 20:05       ` Sakari Ailus
2012-10-15 16:05 ` Sakari Ailus
2012-10-15 18:45   ` Laurent Pinchart
2012-10-15 18:53     ` Chris MacGregor
2012-10-15 19:59       ` Sakari Ailus
2012-10-15 20:10         ` Rémi Denis-Courmont
2012-10-16  1:25         ` Chris MacGregor
2012-10-25  0:47           ` Laurent Pinchart
2012-10-16  6:13     ` Hans Verkuil

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