From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
The "Codec Interface" chapter is poorly named since codecs are just one
use-case of the Memory-to-Memory Interface. Rename it and clean up the
text a bit.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
.../media/uapi/mediactl/request-api.rst | 4 ++--
.../v4l/{dev-codec.rst => dev-mem2mem.rst} | 21 +++++++------------
Documentation/media/uapi/v4l/devices.rst | 2 +-
.../media/uapi/v4l/pixfmt-compressed.rst | 2 +-
Documentation/media/uapi/v4l/vidioc-qbuf.rst | 2 +-
5 files changed, 13 insertions(+), 18 deletions(-)
rename Documentation/media/uapi/v4l/{dev-codec.rst => dev-mem2mem.rst} (79%)
diff --git a/Documentation/media/uapi/mediactl/request-api.rst b/Documentation/media/uapi/mediactl/request-api.rst
index 4b25ad03f45a..1ad631e549fe 100644
--- a/Documentation/media/uapi/mediactl/request-api.rst
+++ b/Documentation/media/uapi/mediactl/request-api.rst
@@ -91,7 +91,7 @@ A request must contain at least one buffer, otherwise ``ENOENT`` is returned.
A queued request cannot be modified anymore.
.. caution::
- For :ref:`memory-to-memory devices <codec>` you can use requests only for
+ For :ref:`memory-to-memory devices <mem2mem>` you can use requests only for
output buffers, not for capture buffers. Attempting to add a capture buffer
to a request will result in an ``EACCES`` error.
@@ -152,7 +152,7 @@ if it had just been allocated.
Example for a Codec Device
--------------------------
-For use-cases such as :ref:`codecs <codec>`, the request API can be used
+For use-cases such as :ref:`codecs <mem2mem>`, the request API can be used
to associate specific controls to
be applied by the driver for the OUTPUT buffer, allowing user-space
to queue many such buffers in advance. It can also take advantage of requests'
diff --git a/Documentation/media/uapi/v4l/dev-codec.rst b/Documentation/media/uapi/v4l/dev-mem2mem.rst
similarity index 79%
rename from Documentation/media/uapi/v4l/dev-codec.rst
rename to Documentation/media/uapi/v4l/dev-mem2mem.rst
index b5e017c17834..69efcc747588 100644
--- a/Documentation/media/uapi/v4l/dev-codec.rst
+++ b/Documentation/media/uapi/v4l/dev-mem2mem.rst
@@ -7,11 +7,11 @@
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
-.. _codec:
+.. _mem2mem:
-***************
-Codec Interface
-***************
+********************************
+Video Memory To Memory Interface
+********************************
A V4L2 codec can compress, decompress, transform, or otherwise convert
video data from one format into another format, in memory. Typically
@@ -25,19 +25,14 @@ memory) stream I/O. An application will have to setup the stream I/O for
both sides and finally call :ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>`
for both capture and output to start the codec.
-Video compression codecs use the MPEG controls to setup their codec
-parameters
-
-.. note::
-
- The MPEG controls actually support many more codecs than
- just MPEG. See :ref:`mpeg-controls`.
+Video compression codecs use codec controls to setup their codec parameters.
+See :ref:`mpeg-controls`.
Memory-to-memory devices function as a shared resource: you can
open the video node multiple times, each application setting up their
-own codec properties that are local to the file handle, and each can use
+own properties that are local to the file handle, and each can use
it independently from the others. The driver will arbitrate access to
-the codec and reprogram it whenever another file handler gets access.
+the hardware and reprogram it whenever another file handler gets access.
This is different from the usual video node behavior where the video
properties are global to the device (i.e. changing something through one
file handle is visible through another file handle).
diff --git a/Documentation/media/uapi/v4l/devices.rst b/Documentation/media/uapi/v4l/devices.rst
index d6fcf3db5909..07f8d047662b 100644
--- a/Documentation/media/uapi/v4l/devices.rst
+++ b/Documentation/media/uapi/v4l/devices.rst
@@ -21,7 +21,7 @@ Interfaces
dev-overlay
dev-output
dev-osd
- dev-codec
+ dev-mem2mem
dev-raw-vbi
dev-sliced-vbi
dev-radio
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
index e4c5e456df59..2675bef3eefe 100644
--- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
@@ -73,7 +73,7 @@ Compressed Formats
- 'MG2S'
- MPEG-2 parsed slice data, as extracted from the MPEG-2 bitstream.
This format is adapted for stateless video decoders that implement a
- MPEG-2 pipeline (using the :ref:`codec` and :ref:`media-request-api`).
+ MPEG-2 pipeline (using the :ref:`mem2mem` and :ref:`media-request-api`).
Metadata associated with the frame to decode is required to be passed
through the ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS`` control and
quantization matrices can optionally be specified through the
diff --git a/Documentation/media/uapi/v4l/vidioc-qbuf.rst b/Documentation/media/uapi/v4l/vidioc-qbuf.rst
index 3259168a7358..c138d149faea 100644
--- a/Documentation/media/uapi/v4l/vidioc-qbuf.rst
+++ b/Documentation/media/uapi/v4l/vidioc-qbuf.rst
@@ -123,7 +123,7 @@ then ``EINVAL`` will be returned.
:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` or calling :ref:`VIDIOC_REQBUFS`
the check for this will be reset.
- For :ref:`memory-to-memory devices <codec>` you can specify the
+ For :ref:`memory-to-memory devices <mem2mem>` you can specify the
``request_fd`` only for output buffers, not for capture buffers. Attempting
to specify this for a capture buffer will result in an ``EACCES`` error.
--
2.20.1
