If colorspace changes, the client needs to renegotiate the pipeline,
otherwise the decoded frame may not be displayed correctly.
When a colorspace change in the stream, the decoder sends a
V4L2_EVENT_SOURCE_CHANGE event with changes set to
V4L2_EVENT_SRC_CH_COLORSPACE. After client receive this source change
event, then client can switch to the correct stream setting. And each
frame can be displayed properly.
So add colorspace as a trigger parameter for dynamic resolution change.
Signed-off-by: Ming Qian <ming.qian@xxxxxxxxxxx>
---
v2
- Add V4L2_EVENT_SRC_CH_COLORSPACE for colorspace source change event
.../userspace-api/media/v4l/dev-decoder.rst | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/Documentation/userspace-api/media/v4l/dev-decoder.rst b/Documentation/userspace-api/media/v4l/dev-decoder.rst
index ef8e8cf31f90..51d6da3eea4a 100644
--- a/Documentation/userspace-api/media/v4l/dev-decoder.rst
+++ b/Documentation/userspace-api/media/v4l/dev-decoder.rst
@@ -784,8 +784,8 @@ before the sequence started. Last of the buffers will have the
must check if there is any pending event and:
* if a ``V4L2_EVENT_SOURCE_CHANGE`` event with ``changes`` set to
- ``V4L2_EVENT_SRC_CH_RESOLUTION`` is pending, the `Dynamic Resolution
- Change` sequence needs to be followed,
+ ``V4L2_EVENT_SRC_CH_RESOLUTION`` or ``V4L2_EVENT_SRC_CH_COLORSPACE`` is pending,
+ the `Dynamic Resolution Change` sequence needs to be followed,
* if a ``V4L2_EVENT_EOS`` event is pending, the `End of Stream` sequence needs
to be followed.
@@ -932,13 +932,17 @@ reflected by corresponding queries):
* the minimum number of buffers needed for decoding,
-* bit-depth of the bitstream has been changed.
+* bit-depth of the bitstream has been changed,
+
+* colorspace of the bitstream has been changed.
Whenever that happens, the decoder must proceed as follows:
1. After encountering a resolution change in the stream, the decoder sends a
``V4L2_EVENT_SOURCE_CHANGE`` event with ``changes`` set to
- ``V4L2_EVENT_SRC_CH_RESOLUTION``.
+ ``V4L2_EVENT_SRC_CH_RESOLUTION``, or a colorspace change in the stream, the
+ decoder sends a ``V4L2_EVENT_SOURCE_CHANGE`` event with ``changes`` set to
+ ``V4L2_EVENT_SRC_CH_COLORSPACE``.
.. important::
@@ -946,6 +950,11 @@ Whenever that happens, the decoder must proceed as follows:
values applying to the stream after the resolution change, including
queue formats, selection rectangles and controls.
+.. note::
+ A ``V4L2_EVENT_SOURCE_CHANGE`` event with ``changes`` set to
+ ``V4L2_EVENT_SRC_CH_RESOLUTION`` will affect the allocation, but
+ ``V4L2_EVENT_SRC_CH_COLORSPACE`` won't.
+
2. The decoder will then process and decode all remaining buffers from before
the resolution change point.
--
2.43.0-rc1
