On 1/12/21 12:05 PM, Hans Verkuil wrote: > On 06/12/2020 11:27, Stanimir Varbanov wrote: >> Add a control to set intra-refresh period. >> >> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx> >> --- >> .../userspace-api/media/v4l/ext-ctrls-codec.rst | 11 +++++++++++ >> drivers/media/v4l2-core/v4l2-ctrls.c | 2 ++ >> include/uapi/linux/v4l2-controls.h | 1 + >> 3 files changed, 14 insertions(+) >> >> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst >> index 454ecd9a0f83..d65d7c1381b7 100644 >> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst >> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst >> @@ -1104,6 +1104,17 @@ enum v4l2_mpeg_video_h264_entropy_mode - >> macroblocks is refreshed until the cycle completes and starts from >> the top of the frame. Applicable to H264, H263 and MPEG4 encoder. >> >> +``V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD (integer)`` >> + Intra macroblock refresh period. This sets the period to refresh >> + the whole frame. With other words, this defines the number of frames > > With -> In > >> + for which the whole frame will be intra-refreshed. An example: >> + setting period to 1 means that the whole frame will be refreshed, >> + setting period to 2 means that the half of macroblocks will be >> + intra-refreshed on frameX and the other half of macroblocks >> + will be refreshed in frameX + 1 and so on. Setting period to zero >> + means no period is specified. >> + Applicable to H264 and HEVC encoders. > > I'm confused. Isn't this the same as V4L2_CID_MPEG_VIDEO_CYCLIC_INTRA_REFRESH_MB? > Except that here you don't give the number of macroblocks but instead the number > of frames it will take to fully refresh a frame and leave it to the driver to > calculate the number of macroblocks? Yes, correct. The periodic control looks more generic because it doesn't limit the type of intra-refresh (cyclic vs random vs adaptive) but instead set the number of frames to fully refresh the whole frame and is also taken from Android mediacodec [1], where the user doesn't care too much what intra-refresh type will be used but instead how much frames are needed to fully refresh. > > If I am right, then you need to clearly document the relationship between the > two controls, and what happens if you set them both. Yep, I can add such description. One note here; the CYCLIC_INTRA_REFRESH_MB and INTRA_REFRESH_PERIOD are not interchangeable because intra-refresh period could use different type of inter-refresh, eg. random vs cyclic. > > It seems the venus driver already supports V4L2_CID_MPEG_VIDEO_CYCLIC_INTRA_REFRESH_MB, > so why add this control as well? The cyclic intra-refresh control in Venus driver is just enumerable but ignored when set, in other words it does nothing. > > Regards, > > Hans > [1] https://developer.android.com/reference/android/media/MediaFormat#KEY_INTRA_REFRESH_PERIOD -- regards, Stan
