By setting the V4L2_BUF_FLAG_HEADERS_ONLY flag,
hint the vb2 only contains stream header,
but does not contain any frame data.
This flag needs to be used when header mode is set to
V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE.
Signed-off-by: Ming Qian <ming.qian@xxxxxxx>
---
Documentation/userspace-api/media/v4l/buffer.rst | 11 +++++++++++
.../userspace-api/media/v4l/ext-ctrls-codec.rst | 10 +++++++---
include/uapi/linux/videodev2.h | 2 ++
3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
index 4638ec64db00..18a6f5fcc822 100644
--- a/Documentation/userspace-api/media/v4l/buffer.rst
+++ b/Documentation/userspace-api/media/v4l/buffer.rst
@@ -607,6 +607,17 @@ Buffer Flags
the format. Any subsequent call to the
:ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl will not block anymore,
but return an ``EPIPE`` error code.
+ * .. _`V4L2-BUF-FLAG-HEADERS-ONLY`:
+
+ - ``V4L2_BUF_FLAG_HEADERS_ONLY``
+ - 0x00200000
+ - This flag may be set when the buffer only contains codec
+ header, but does not contain any frame data. Usually the codec
+ header is merged to the next idr frame, with the flag
+ ``V4L2_BUF_FLAG_KEYFRAME``, but there is still some scenes that will
+ split the header and queue it separately. This flag can set only when
+ codec support V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE,
+ and the header mode is set to V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE
* .. _`V4L2-BUF-FLAG-REQUEST-FD`:
- ``V4L2_BUF_FLAG_REQUEST_FD``
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index 6183f43f4d73..478b6af4205d 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -1386,8 +1386,12 @@ enum v4l2_mpeg_video_intra_refresh_period_type -
(enum)
enum v4l2_mpeg_video_header_mode -
- Determines whether the header is returned as the first buffer or is
- it returned together with the first frame. Applicable to encoders.
+ Determines whether the header is returned as the first buffer
+ with flag V4L2_BUF_FLAG_HEADERS_ONLY or is
+ it returned together with the first frame.
+ Applicable to encoders and decoders.
+ If it's not implemented in a driver,
+ V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME is to be assumed,
Possible values are:
.. raw:: latex
@@ -1401,7 +1405,7 @@ enum v4l2_mpeg_video_header_mode -
:stub-columns: 0
* - ``V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE``
- - The stream header is returned separately in the first buffer.
+ - The stream header is returned separately in the first buffer with the flag V4L2_BUF_FLAG_HEADERS_ONLY.
* - ``V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME``
- The stream header is returned together with the first encoded
frame.
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 5311ac4fde35..6fd96acd6080 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1131,6 +1131,8 @@ static inline __u64 v4l2_timeval_to_ns(const struct timeval *tv)
#define V4L2_BUF_FLAG_TSTAMP_SRC_SOE 0x00010000
/* mem2mem encoder/decoder */
#define V4L2_BUF_FLAG_LAST 0x00100000
+/* Buffer only contains codec header */
+#define V4L2_BUF_FLAG_HEADERS_ONLY 0x00200000
/* request_fd is valid */
#define V4L2_BUF_FLAG_REQUEST_FD 0x00800000
--
2.36.1
