FFmpeg 4.1.11
Since* 3.4
#

Map hardware frames to system memory or to another device.

This filter has several different modes of operation; which one is used depends on the input and output formats:

The following additional parameters are accepted:

mode

Set the frame mapping mode. Some combination of:

read

The mapped frame should be readable.

write

The mapped frame should be writeable.

overwrite

The mapping will always overwrite the entire frame.

This may improve performance in some cases, as the original contents of the frame need not be loaded.

direct

The mapping must not involve any copying.

Indirect mappings to copies of frames are created in some cases where either direct mapping is not possible or it would have unexpected properties. Setting this flag ensures that the mapping is direct and will fail if that is not possible.

Defaults to read+write if not specified.

derive_device type

Rather than using the device supplied at initialisation, instead derive a new device of type type from the device the input frames exist on.

reverse

In a hardware to hardware mapping, map in reverse - create frames in the sink and map them back to the source. This may be necessary in some cases where a mapping in one direction is required but only the opposite direction is supported by the devices being used.

This option is dangerous - it may break the preceding filter in undefined ways if there are any additional constraints on that filter’s output. Do not use it without fully understanding the implications of its use.