Hi, > -----Original Message----- > From: Hans Verkuil [mailto:hverkuil@xxxxxxxxx] > Sent: 22 June 2011 10:26 > To: Kamil Debski > Cc: linux-media@xxxxxxxxxxxxxxx; m.szyprowski@xxxxxxxxxxx; > kyungmin.park@xxxxxxxxxxx; jaeryul.oh@xxxxxxxxxxx; > laurent.pinchart@xxxxxxxxxxxxxxxx; jtp.park@xxxxxxxxxxx > Subject: Re: [PATCH 2/4 v9] v4l: add control definitions for codec devices. > > On Tuesday, June 14, 2011 18:36:54 Kamil Debski wrote: > > Add control definitions and documentation for controls > > specific to codec devices. > > > > Signed-off-by: Kamil Debski <k.debski@xxxxxxxxxxx> > > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> > > --- > > Documentation/DocBook/media/v4l/controls.xml | 958 > ++++++++++++++++++++++++++ > > include/linux/videodev2.h | 171 +++++ > > 2 files changed, 1129 insertions(+), 0 deletions(-) > > > > diff --git a/Documentation/DocBook/media/v4l/controls.xml > b/Documentation/DocBook/media/v4l/controls.xml > > index 6880798..6b0d06a 100644 > > --- a/Documentation/DocBook/media/v4l/controls.xml > > +++ b/Documentation/DocBook/media/v4l/controls.xml > > @@ -325,6 +325,22 @@ minimum value disables backlight > compensation.</entry> > > <constant>V4L2_CID_ILLUMINATORS_2</constant> + 1).</entry> > > </row> > > <row> > > + ... > > + > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE</constan > t> </entry> > > + <entry>boolean</entry> > > + </row> > > + <row><entry spanname="descr">If enabled the decoder expects a > single slice in one OUTPUT buffer, otherwise > > +the decoder expects a single frame in one input buffer. Applicable to the > decoder, all codecs. > > 'in one OUTPUT buffer' vs 'in one input buffer'. Perhaps rewriting it like > this is better: > > <row><entry spanname="descr">If enabled the decoder expects to > receive a single slice per buffer, otherwise > the decoder expects a single frame in per buffer. Applicable to the decoder, > all codecs. > > BTW: 'all codecs'? Your decoder hardware can handle e.g. MPEG-2 sliced input? > I thought slices were specific to e.g. MPEG4/H264? Just checking... I've checked the H263 spec and it mentions slice, same for MPEG2 (this site http://goo.gl/vXUEb mentions slices). It could be better to explicitly list the codecs, as there might be a codec that doesn't support slices. > > > +</entry> > > + </row> > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_ENABLE</constant>&n > bsp;</entry> > > + <entry>boolean</entry> > > + </row> > > + <row><entry spanname="descr">Enable writing sample aspect ratio > in the Video Usability Information. > > +Applicable to the H264 encoder.</entry> > > + </row> > > + ... > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP</constant> > </entry> > > + <entry>integer</entry> > > + </row> > > + <row><entry spanname="descr">Quantization parameter for an I > frame for H263. Valid range: from 1 to 31.</entry> > > Is this range defined by the H263 standard? If not, then you shouldn't > mention > the range as it is hardware dependent. Yes it is defined in the standard. > > > + </row> > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H263_MIN_QP</constant> </en > try> .... > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_VBV_SIZE</constant> </entry > > > > + <entry>integer</entry> > > + </row> > > + <row><entry spanname="descr">The Video Buffer Verifier size in > kilobytes, it used as a limitation of frame skip. > > Typo: 'it used' -> 'it is used' > > I think it would be good to either give some background information here, or > refer > to the standard for that information. Ok, will do. > > +Applicable to the MPEG1, MPEG2, MPEG4 encoders.</entry> > > + </row> > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_CPB_SIZE</constant> </ > entry> > > + <entry>integer</entry> > > + </row> > > + <row><entry spanname="descr">The Coded Picture Buffer size in > kilobytes, it used as a limitation of frame skip. > > Same typo. > > > +Applicable to the H264 encoder.</entry> > > + </row> > > + > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_I_PERIOD</constant> </ > entry> > > + <entry>integer</entry> > > + </row> > > + <row><entry spanname="descr">Period between I-frames in the open > GOP for H264. In case of an open GOP > > +this is the period between two I-frames. The period between IDR > (Instantaneous Decoding Refresh) frames is taken from the GOP_SIZE control. > > +An IDR frame, which stands for Instantaneous Decoding Refresh is an I- > frame after which no prior frames are > > +referenced. This means that a stream can be restarted from an IDR frame > without the need to store or decode any > > +previous frames. Applicable to the H264 encoder.</entry> > > + </row> > > + ... > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_RES</constant>&nb > sp;</entry> > > + <entry>integer</entry> > > + </row><row><entry spanname="descr">vop_time_increment_resolution > value for MPEG4. Applicable to the MPEG4 encoder.</entry> > > + </row> > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_VOP_TIME_INC</constant>&nb > sp;</entry> > > + <entry>integer</entry> > > + </row><row><entry spanname="descr">vop_time_increment value for > MPEG4. Applicable to the MPEG4 encoder.</entry> > > How should these two controls be used? Are you supposed to set them? Or do > they > have suitable default values? They are used only in MPEG4 and are used instead of S_PARM to set fps. You are supposed to set them, but I think the driver could set a default value (such as vop_time_res = 30000 and vop_time_res_increment = 1000). > > + </row> > > + > > + </tbody> > > + </tgroup> > > + </table> > > + </section> > > + ... > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_DECODER_H264_DISPLAY_DELAY > </constant> </entry> > > + <entry>integer</entry> > > + </row><row><entry spanname="descr">Display delay value for H264 > decoder.</entry> > > What's the unit of this control? Frames? Slices? Buffers? It is expressed in frames, I will add it to the documentation. > > + </row> > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P</co > nstant> </entry> > > + <entry>integer</entry> > > + </row><row><entry spanname="descr">The number of reference > pictures used for encoding a P picture. > > +Applicable to the H264 encoder.</entry> > > + </row> > > + <row><entry></entry></row> > > + <row> ... > > + > <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_DISABLED</constant> </ > entry> > > + <entry>Frame skip mode is disabled.</entry> > > + </row> > > + <row> > > + > <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_LEVEL_LIMIT</constant>  > ;</entry> > > + <entry>Frame skip mode enabled and buffer limit is set by > the chosen level.</entry> > > With which control do I set that level? *_MPEG4_LEVEL and *_H264_LEVEL, I will add some clarification. > > + </row> > > + <row> > > + > <entry><constant>V4L2_MPEG_MFC51_FRAME_SKIP_MODE_VBV_LIMIT</constant> < > /entry> > > + <entry>Frame skip mode enabled and buffer limit is set by > the VBV buffer size control.</entry> > > VBV or H264_CPB. Perhaps this should be renamed SKIP_MODE_BUF_LIMIT with > references > to the VBV and H264_CPB controls. Yes, it is a good idea to rename the control. > > + </row> > > + </tbody> > > + </entrytbl> > > + </row> > > + <row><entry></entry></row> > > + <row> > > + <entry > spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_RC_FIXED_TARGET_BIT</const > ant> </entry> ... Best regards, -- Kamil Debski Linux Platform Group Samsung Poland R&D Center -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
