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| author | Hans Verkuil <hans.verkuil@cisco.com> | 2018-08-15 09:10:59 -0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2018-08-31 09:31:28 -0400 |
| commit | a125385c9b17de4e555cc2057593ab11da5edc70 (patch) | |
| tree | e83af99c720a4c0aa7caea2542a5cfb476812c95 /Documentation/media | |
| parent | fb98e29ff1ea5a8118265d11f0e03bc8608a49cb (diff) | |
| download | blackbird-op-linux-a125385c9b17de4e555cc2057593ab11da5edc70.tar.gz blackbird-op-linux-a125385c9b17de4e555cc2057593ab11da5edc70.zip | |
media: vidioc-g-dv-timings.rst: document V4L2_DV_FL_CAN_DETECT_REDUCED_FPS
Document the new V4L2_DV_FL_CAN_DETECT_REDUCED_FPS flag and
update the V4L2_DV_FL_REDUCED_FPS description since it can now
also be used with receivers.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/media')
| -rw-r--r-- | Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst b/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst index 1a034e825161..35cba2c8d459 100644 --- a/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst +++ b/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst @@ -257,14 +257,19 @@ EBUSY will also be cleared. This is a read-only flag, applications must not set this. * - ``V4L2_DV_FL_REDUCED_FPS`` - - CEA-861 specific: only valid for video transmitters, the flag is - cleared by receivers. It is also only valid for formats with the - ``V4L2_DV_FL_CAN_REDUCE_FPS`` flag set, for other formats the - flag will be cleared by the driver. If the application sets this - flag, then the pixelclock used to set up the transmitter is - divided by 1.001 to make it compatible with NTSC framerates. If - the transmitter can't generate such frequencies, then the flag - will also be cleared. + - CEA-861 specific: only valid for video transmitters or video + receivers that have the ``V4L2_DV_FL_CAN_DETECT_REDUCED_FPS`` + set. This flag is cleared otherwise. It is also only valid for + formats with the ``V4L2_DV_FL_CAN_REDUCE_FPS`` flag set, for other + formats the flag will be cleared by the driver. + + If the application sets this flag for a transmitter, then the + pixelclock used to set up the transmitter is divided by 1.001 to + make it compatible with NTSC framerates. If the transmitter can't + generate such frequencies, then the flag will be cleared. + + If a video receiver detects that the format uses a reduced framerate, + then it will set this flag to signal this to the application. * - ``V4L2_DV_FL_HALF_LINE`` - Specific to interlaced formats: if set, then the vertical backporch of field 1 (aka the odd field) is really one half-line @@ -294,3 +299,9 @@ EBUSY - If set, then the hdmi_vic field is valid and contains the Video Identification Code as per the HDMI standard (HDMI Vendor Specific InfoFrame). + * - ``V4L2_DV_FL_CAN_DETECT_REDUCED_FPS`` + - CEA-861 specific: only valid for video receivers, the flag is + cleared by transmitters. + If set, then the hardware can detect the difference between + regular framerates and framerates reduced by 1000/1001. E.g.: + 60 vs 59.94 Hz, 30 vs 29.97 Hz or 24 vs 23.976 Hz. |
