Le mardi 28 juin 2022 à 10:19 +0800, Ming Qian a écrit : > By setting the V4L2_BUF_FLAG_CODECCONFIG flag, > user-space should be able to hint decoder > the vb2 only contains codec config header, > but does not contain any frame data. > It's only used for parsing header, and can't be decoded. This is copied from OMX specification. I think we we import this, we should at least refer to the original. > > Current, it's usually used by android. > > Signed-off-by: Ming Qian <ming.qian@xxxxxxx> > --- > Documentation/userspace-api/media/v4l/buffer.rst | 9 +++++++++ > include/uapi/linux/videodev2.h | 2 ++ > 2 files changed, 11 insertions(+) > > diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst > index 4638ec64db00..acdc4556f4f4 100644 > --- a/Documentation/userspace-api/media/v4l/buffer.rst > +++ b/Documentation/userspace-api/media/v4l/buffer.rst > @@ -607,6 +607,15 @@ 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-CODECCONFIG`: > + > + - ``V4L2_BUF_FLAG_CODECCONFIG`` > + - 0x00200000 > + - This flag may be set when the buffer only contains codec config > + header, but does not contain any frame data. Usually the codec config > + 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. I think the documentation is clear. Now, if a driver uses this, will existing userland (perhaps good to check GStreamer, FFMPEG and Chromium ?) will break ? So we need existing driver to do this when flagged to, and just copy/append when the userland didn't opt-in that feature ? > * .. _`V4L2-BUF-FLAG-REQUEST-FD`: > > - ``V4L2_BUF_FLAG_REQUEST_FD`` > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > index 5311ac4fde35..8708ef257710 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_CODECCONFIG 0x00200000 > /* request_fd is valid */ > #define V4L2_BUF_FLAG_REQUEST_FD 0x00800000 >
