diff options
Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst | 36 |
1 files changed, 27 insertions, 9 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..5712bd48e687 100644 --- a/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst +++ b/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst @@ -1,4 +1,11 @@ -.. -*- coding: utf-8; mode: rst -*- +.. Permission is granted to copy, distribute and/or modify this +.. document under the terms of the GNU Free Documentation License, +.. Version 1.1 or any later version published by the Free Software +.. Foundation, with no Invariant Sections, no Front-Cover Texts +.. and no Back-Cover Texts. A copy of the license is included at +.. Documentation/media/uapi/fdl-appendix.rst. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections .. _VIDIOC_G_DV_TIMINGS: @@ -257,14 +264,19 @@ 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 +306,9 @@ 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. |