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Message-id: <051c01cf1dcf$1132ee60$3398cb20$%debski@samsung.com>
Date: Thu, 30 Jan 2014 16:22:18 +0100
From: Kamil Debski <k.debski@...sung.com>
To: 'Hans Verkuil' <hverkuil@...all.nl>,
'Amit Grover' <amit.grover@...sung.com>
Cc: linux-media@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
kyungmin.park@...sung.com, prabhakar.csengg@...il.com,
Sylwester Nawrocki <s.nawrocki@...sung.com>,
hans.verkuil@...co.com, swaminath.p@...sung.com,
jtp.park@...sung.com, Rrob@...dley.net, andrew.smirnov@...il.com,
anatol.pomozov@...il.com, jmccrohan@...il.com, joe@...ches.com,
awalls@...metrocast.net, arun.kk@...sung.com,
austin.lobo@...sung.com
Subject: RE: [PATCH v2 1/2] drivers/media: v4l2: Add settings for Horizontal
and Vertical MV Search Range
Hi Hans, Amit,
> From: Hans Verkuil [mailto:hverkuil@...all.nl]
> Sent: Thursday, January 30, 2014 8:36 AM
>
> On 01/30/2014 06:42 AM, Amit Grover wrote:
> > Adding V4L2 controls for horizontal and vertical search range in
> > pixels for motion estimation module in video encoder.
> >
> > Signed-off-by: Swami Nathan <swaminath.p@...sung.com>
> > Signed-off-by: Amit Grover <amit.grover@...sung.com>
> > ---
> > Documentation/DocBook/media/v4l/controls.xml | 20
> ++++++++++++++++++++
> > drivers/media/v4l2-core/v4l2-ctrls.c | 14 ++++++++++++++
> > include/uapi/linux/v4l2-controls.h | 2 ++
> > 3 files changed, 36 insertions(+)
> >
> > diff --git a/Documentation/DocBook/media/v4l/controls.xml
> > b/Documentation/DocBook/media/v4l/controls.xml
> > index 7a3b49b..be04d18 100644
> > --- a/Documentation/DocBook/media/v4l/controls.xml
> > +++ b/Documentation/DocBook/media/v4l/controls.xml
> > @@ -2258,6 +2258,26 @@ Applicable to the MPEG1, MPEG2, MPEG4
> > encoders.</entry> VBV buffer control.</entry>
> > </row>
> >
> > + <row><entry></entry></row>
> > + <row id=""v4l2-mpeg-video-hor-search-range">
> > + <entry
> spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE</constant
> > </entry>
> > + <entry>integer</entry>
> > + </row>
> > + <row><entry spanname="descr">Horizontal search range
> defines
> > +maximum horizontal search area in pixels to search and match for the
> > +present Macroblock (MB) in the reference picture. This V4L2 control
> macro is used to set horizontal search range for motion estimation
> module in video encoder.</entry>
> > + </row>
> > +
> > + <row><entry></entry></row>
> > + <row id="v4l2-mpeg-video-vert-search-range">
> > + <entry
> spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE</constant
> > </entry>
> > + <entry>integer</entry>
>
> These two controls sound very mfc specific as opposed to being part of
> the standard.
> If so, then they should be named V4L2_CID_MPEG_MFC51_*.
mencoder has an option to set motion vector search radius.
>From man mencoder:
me_range=<4-64>
radius of exhaustive or multi-hexagon motion search
(default:
16)
So I think it could be applicable to other hardware codecs as well.
> Also, for which codecs are these controls applicable?
Isn't the choice of motion estimation algorithm (and its parameters)
codec agnostic, as long as the restrictions of the standard are honoured?
>
> > + </row>
> > + <row><entry spanname="descr">Vertical search range defines
> maximum
> > +vertical search area in pixels to search and match for the present
> > +Macroblock (MB) in the reference picture. This V4L2 control macro is
> used to set vertical search range for motion estimation module in video
> encoder.</entry>
> > + </row>
> > +
> > <row><entry></entry></row>
> > <row>
> > <entry
> >
> spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_CPB_SIZE</constant>&n
> > bsp;</entry> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> > b/drivers/media/v4l2-core/v4l2-ctrls.c
> > index fb46790..e775388 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> > @@ -735,6 +735,8 @@ const char *v4l2_ctrl_get_name(u32 id)
> > case V4L2_CID_MPEG_VIDEO_DEC_PTS: return
"Video
> Decoder PTS";
> > case V4L2_CID_MPEG_VIDEO_DEC_FRAME: return
"Video
> Decoder Frame Count";
> > case V4L2_CID_MPEG_VIDEO_VBV_DELAY: return
"Initial
> Delay for VBV Control";
> > + case V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE: return
> "Horizontal MV Search Range";
> > + case V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE: return
> "Vertical MV Search Range";
> > case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER: return
> "Repeat Sequence Header";
> >
> > /* VPX controls */
> > @@ -905,6 +907,18 @@ void v4l2_ctrl_fill(u32 id, const char **name,
> enum v4l2_ctrl_type *type,
> > *min = 0;
> > *max = *step = 1;
> > break;
> > + case V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE:
> > + *type = V4L2_CTRL_TYPE_INTEGER;
> > + *min = 16;
> > + *max = 128;
> > + *step = 16;
>
> Weird range, why not use range 1-8?
If the search range is represented in pixels, then pixels should be used.
It the control is also used in other hardware, then I think it the values
should not be limited in this way here. For example mencoder accepts the
value between 4 and 64. The range and step could be limited in the
s5p_mfc_enc.c.
>
> > + break;
> > + case V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE:
> > + *type = V4L2_CTRL_TYPE_INTEGER;
> > + *min = 16;
> > + *max = 128;
> > + *step = 16;
> > + break;
> > case V4L2_CID_PAN_RESET:
> > case V4L2_CID_TILT_RESET:
> > case V4L2_CID_FLASH_STROBE:
> > diff --git a/include/uapi/linux/v4l2-controls.h
> > b/include/uapi/linux/v4l2-controls.h
> > index 1666aab..80e1def 100644
> > --- a/include/uapi/linux/v4l2-controls.h
> > +++ b/include/uapi/linux/v4l2-controls.h
> > @@ -372,6 +372,8 @@ enum v4l2_mpeg_video_multi_slice_mode {
> > #define V4L2_CID_MPEG_VIDEO_DEC_FRAME
> (V4L2_CID_MPEG_BASE+224)
> > #define V4L2_CID_MPEG_VIDEO_VBV_DELAY
> (V4L2_CID_MPEG_BASE+225)
> > #define V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER
> (V4L2_CID_MPEG_BASE+226)
> > +#define V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE
> (V4L2_CID_MPEG_BASE+227)
> > +#define V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE
> (V4L2_CID_MPEG_BASE+228)
> >
> > #define V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP
> (V4L2_CID_MPEG_BASE+300)
> > #define V4L2_CID_MPEG_VIDEO_H263_P_FRAME_QP
> (V4L2_CID_MPEG_BASE+301)
> >
>
> Regards,
>
> Hans
Best wishes,
--
Kamil Debski
Samsung R&D Institute Poland
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