media: v4l2-ctrl: Make display delay and display enable std controls

Make display delay and display delay enable MFC controls standard v4l
controls. This will allow reuse of the controls for other decoder
drivers. Also the new proposed controls are now codec agnostic because
they could be used for any codec.

Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index 7ee8ae073b91..7e8ab168571d 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -679,6 +679,21 @@ enum v4l2_mpeg_video_frame_skip_mode -
     otherwise the decoder expects a single frame in per buffer.
     Applicable to the decoder, all codecs.
 
+``V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY_ENABLE (boolean)``
+    If the display delay is enabled then the decoder is forced to return
+    a CAPTURE buffer (decoded frame) after processing a certain number
+    of OUTPUT buffers. The delay can be set through
+    ``V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY``. This
+    feature can be used for example for generating thumbnails of videos.
+    Applicable to the decoder.
+
+``V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY (integer)``
+    Display delay value for decoder. The decoder is forced to
+    return a decoded frame after the set 'display delay' number of
+    frames. If this number is low it may result in frames returned out
+    of display order, in addition the hardware may still be using the
+    returned buffer as a reference picture for subsequent frames.
+
 ``V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_ENABLE (boolean)``
     Enable writing sample aspect ratio in the Video Usability
     Information. Applicable to the H264 encoder.