[PATCHv3 5/5] dev-encoder.rst: add reference to V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL

[Hans Verkuil <hverkuil-cisco@xxxxxxxxx>]

Setting the stateful encoder capture frame interval is only supported
if this flag is set. Document this.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
 Documentation/userspace-api/media/v4l/dev-encoder.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/userspace-api/media/v4l/dev-encoder.rst b/Documentation/userspace-api/media/v4l/dev-encoder.rst
index aace7b812a9c..c3a21bfe0052 100644
--- a/Documentation/userspace-api/media/v4l/dev-encoder.rst
+++ b/Documentation/userspace-api/media/v4l/dev-encoder.rst
@@ -281,7 +281,8 @@ Initialization
 5. **Optional** Set the coded frame interval on the ``CAPTURE`` queue via
    :c:func:`VIDIOC_S_PARM`. This is only necessary if the coded frame
    interval is different from the raw frame interval, which is typically
-   the case for off-line encoding.
+   the case for off-line encoding. Support for this feature is signalled
+   by the :ref:`V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL <fmtdesc-flags>` format flag.
 
    * ** Required fields:**
 
-- 
2.25.1