From: Maxime Jourdan <>

Add an enum_fmt format flag to specifically tag coded formats where
dynamic resolution switching is supported by the device.

This is useful for some codec drivers that can support dynamic
resolution switching for one or more of their listed coded formats. It
allows userspace to know whether it should extract the video parameters
itself, or if it can rely on the device to send V4L2_EVENT_SOURCE_CHANGE
when such changes are detected.

Signed-off-by: Maxime Jourdan <>
Signed-off-by: Hans Verkuil <>
[ added flag to videodev2.h.rst.exceptions]
[ updated commit text: 'one or more' instead of 'all']
Acked-by: Tomasz Figa <>
 Documentation/media/uapi/v4l/vidioc-enum-fmt.rst | 8 ++++++++
 Documentation/media/videodev2.h.rst.exceptions   | 1 +
 include/uapi/linux/videodev2.h                   | 1 +
 3 files changed, 10 insertions(+)

diff --git a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst 
index ebc05ce74bdf..719f1ed64f7d 100644
--- a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
+++ b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
@@ -135,6 +135,14 @@ one until ``EINVAL`` is returned.
        between frames/fields. This flag can only be used in combination with
        the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to compressed
        formats only. This flag is valid for stateful decoders only.
+      - 0x0008
+      - Dynamic resolution switching is supported by the device for this
+       compressed bytestream format (aka coded format). It will notify the user
+       via the event ``V4L2_EVENT_SOURCE_CHANGE`` when changes in the video
+       parameters are detected. This flag can only be used in combination
+       with the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to
+       compressed formats only.
 Return Value
diff --git a/Documentation/media/videodev2.h.rst.exceptions 
index a0640b6d0f68..adeb6b7a15cb 100644
--- a/Documentation/media/videodev2.h.rst.exceptions
+++ b/Documentation/media/videodev2.h.rst.exceptions
@@ -181,6 +181,7 @@ replace define V4L2_PIX_FMT_FLAG_PREMUL_ALPHA 
 replace define V4L2_FMT_FLAG_COMPRESSED fmtdesc-flags
 replace define V4L2_FMT_FLAG_EMULATED fmtdesc-flags
 replace define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM fmtdesc-flags
+replace define V4L2_FMT_FLAG_DYN_RESOLUTION fmtdesc-flags
 # V4L2 timecode types
 replace define V4L2_TC_TYPE_24FPS timecode-type
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 67077d52c59d..530638dffd93 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -777,6 +777,7 @@ struct v4l2_fmtdesc {
 #define V4L2_FMT_FLAG_COMPRESSED               0x0001
 #define V4L2_FMT_FLAG_EMULATED                 0x0002
+#define V4L2_FMT_FLAG_DYN_RESOLUTION           0x0008
        /* Frame Size and frame rate enumeration */

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