Re: [RFC PATCH v7 11/13] media: uapi: Add audio rate controls support

[Shengjiu Wang]

On Wed, Oct 25, 2023 at 6:47 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
>
> On 20/10/2023 11:30, Shengjiu Wang wrote:
> > Add V4L2_CID_M2M_AUDIO_SOURCE_RATE and V4L2_CID_M2M_AUDIO_DEST_RATE
> > new IDs for rate control.
> >
> > Add V4L2_CID_M2M_AUDIO_SOURCE_RATE_OFFSET and
> > V4L2_CID_M2M_AUDIO_DEST_RATE_OFFSET for clock drift.
> >
> > Signed-off-by: Shengjiu Wang <shengjiu.wang@xxxxxxx>
> > ---
> >  .../media/v4l/ext-ctrls-audio-m2m.rst          | 18 ++++++++++++++++++
> >  drivers/media/v4l2-core/v4l2-ctrls-defs.c      | 12 ++++++++++++
> >  include/uapi/linux/v4l2-controls.h             |  5 +++++
> >  3 files changed, 35 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-audio-m2m.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-audio-m2m.rst
> > index 82d2ecedbfee..e6972a2d3b17 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-audio-m2m.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-audio-m2m.rst
> > @@ -19,3 +19,21 @@ Audio M2M Control IDs
> >      The Audio M2M class descriptor. Calling
> >      :ref:`VIDIOC_QUERYCTRL` for this control will
> >      return a description of this control class.
> > +
> > +.. _v4l2-audio-asrc:
> > +
> > +``V4L2_CID_M2M_AUDIO_SOURCE_RATE``
>
> Add ' (integer menu)' after the name.
>
> > +    Sets the audio source rate, unit is (Hz)
>
> (Hz) -> Hz.
>
> General question: is 'rate' good enough or should it be 'sample rate'?

Ok, will use 'sample rate'.

Best regards
Wang shengjiu
>
> > +
> > +``V4L2_CID_M2M_AUDIO_DEST_RATE``
> > +    Sets the audio destination rate, unit is (Hz)
>
> Ditto here.
>
> > +
> > +``V4L2_CID_M2M_AUDIO_SOURCE_RATE_OFFSET``
>
> Add ' (fixed point)' after the name.
>
> > +    Sets the offset for audio source rate, unit is (Hz).
>
> for -> from the
>
> (Hz) -> Hz
>
> > +    Offset expresses the drift of clock if there is. It is
> > +    equal to real rate minus ideal rate.
>
> How about:
>
> The offset compensates for any clock drift. The actual source audio
> rate is the ideal source audio rate from ``V4L2_CID_M2M_AUDIO_SOURCE_RATE``
> plus this fixed point offset.
>
> > +
> > +``V4L2_CID_M2M_AUDIO_DEST_RATE_OFFSET``
> > +    Sets the offset for audio destination rate, unit is (Hz)
> > +    Offset expresses the drift of clock if there is. It is
> > +    equal to real rate minus ideal rate.
>
> Same changes as for V4L2_CID_M2M_AUDIO_SOURCE_RATE_OFFSET.
>
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > index 2a85ea3dc92f..b695cbdd1f6e 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > @@ -1245,6 +1245,10 @@ const char *v4l2_ctrl_get_name(u32 id)
> >
> >       /* Audio M2M controls */
> >       case V4L2_CID_M2M_AUDIO_CLASS:  return "Audio M2M Controls";
> > +     case V4L2_CID_M2M_AUDIO_SOURCE_RATE:    return "Audio Source Sample Rate";
> > +     case V4L2_CID_M2M_AUDIO_DEST_RATE:      return "Audio Dest Sample Rate";
> > +     case V4L2_CID_M2M_AUDIO_SOURCE_RATE_OFFSET:     return "Audio Source Sample Rate Offset";
> > +     case V4L2_CID_M2M_AUDIO_DEST_RATE_OFFSET:       return "Audio Dest Sample Rate Offset";
>
> Related to my question above: "Sample Rate" or just "Rate"? Whatever we pick, it should
> be consistent.
>
> >       default:
> >               return NULL;
> >       }
> > @@ -1606,6 +1610,14 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> >       case V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY:
> >               *type = V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY;
> >               break;
> > +     case V4L2_CID_M2M_AUDIO_SOURCE_RATE:
> > +     case V4L2_CID_M2M_AUDIO_DEST_RATE:
> > +             *type = V4L2_CTRL_TYPE_INTEGER_MENU;
> > +             break;
> > +     case V4L2_CID_M2M_AUDIO_SOURCE_RATE_OFFSET:
> > +     case V4L2_CID_M2M_AUDIO_DEST_RATE_OFFSET:
> > +             *type = V4L2_CTRL_TYPE_FIXED_POINT;
> > +             break;
> >       default:
> >               *type = V4L2_CTRL_TYPE_INTEGER;
> >               break;
> > diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> > index eb0f0a76f867..d433c6f0b533 100644
> > --- a/include/uapi/linux/v4l2-controls.h
> > +++ b/include/uapi/linux/v4l2-controls.h
> > @@ -3498,4 +3498,9 @@ struct v4l2_ctrl_av1_film_grain {
> >  #define V4L2_CID_M2M_AUDIO_CLASS_BASE  (V4L2_CTRL_CLASS_M2M_AUDIO | 0x900)
> >  #define V4L2_CID_M2M_AUDIO_CLASS       (V4L2_CTRL_CLASS_M2M_AUDIO | 1)
> >
> > +#define V4L2_CID_M2M_AUDIO_SOURCE_RATE       (V4L2_CID_M2M_AUDIO_CLASS_BASE + 0)
> > +#define V4L2_CID_M2M_AUDIO_DEST_RATE (V4L2_CID_M2M_AUDIO_CLASS_BASE + 1)
> > +#define V4L2_CID_M2M_AUDIO_SOURCE_RATE_OFFSET        (V4L2_CID_M2M_AUDIO_CLASS_BASE + 2)
> > +#define V4L2_CID_M2M_AUDIO_DEST_RATE_OFFSET  (V4L2_CID_M2M_AUDIO_CLASS_BASE + 3)
> > +
> >  #endif
>
> Regards,
>
>         Hans