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diff --git a/Documentation/media/uapi/v4l/dev-mem2mem.rst b/Documentation/media/uapi/v4l/dev-mem2mem.rst deleted file mode 100644 index 67a980818dc8..000000000000 --- a/Documentation/media/uapi/v4l/dev-mem2mem.rst +++ /dev/null @@ -1,42 +0,0 @@ -.. Permission is granted to copy, distribute and/or modify this -.. document under the terms of the GNU Free Documentation License, -.. Version 1.1 or any later version published by the Free Software -.. Foundation, with no Invariant Sections, no Front-Cover Texts -.. and no Back-Cover Texts. A copy of the license is included at -.. Documentation/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _mem2mem: - -******************************** -Video Memory-To-Memory Interface -******************************** - -A V4L2 memory-to-memory device can compress, decompress, transform, or -otherwise convert video data from one format into another format, in memory. -Such memory-to-memory devices set the ``V4L2_CAP_VIDEO_M2M`` or -``V4L2_CAP_VIDEO_M2M_MPLANE`` capability. Examples of memory-to-memory -devices are codecs, scalers, deinterlacers or format converters (i.e. -converting from YUV to RGB). - -A memory-to-memory video node acts just like a normal video node, but it -supports both output (sending frames from memory to the hardware) -and capture (receiving the processed frames from the hardware into -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 hardware. - -Memory-to-memory devices function as a shared resource: you can -open the video node multiple times, each application setting up their -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 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). - -One of the most common memory-to-memory device is the codec. Codecs -are more complicated than most and require additional setup for -their codec parameters. This is done through codec controls. -See :ref:`mpeg-controls`. |