media/v4l/dev-subdev.rst

79 Pad-level Formats
84     Pad-level formats are only applicable to very complex devices that
126 can expose pad-level image format configuration to applications. When
130 negotiate formats on a per-pad basis.
138 Pad-level image format configuration support can be tested by calling
139 the :ref:`VIDIOC_SUBDEV_G_FMT` ioctl on pad
140 0. If the driver returns an ``EINVAL`` error code pad-level format
186 or active format is set on a pad, corresponding formats on other pads of
192    a format on a source pad should not modify the format on any sink
193    pad.
209 list entity names and pad numbers).
307 1. Initial state. The sensor source pad format is set to its native 3MP
310    values, as well as the compose rectangle on the scaler's sink pad.
312 2. The application configures the frontend sink pad format's size to
314    driver propagates the format to the frontend source pad.
316 3. The application configures the scaler sink pad format's size to
319    on the sink pad is set to V4L2_MBUS_FMT_SGRBG_1X8. The driver
321    scaler's sink pad, and the format to the scaler source pad.
324    rectangle of the scaler's sink pad 1280x960. The driver propagates
325    the size to the scaler's source pad format.
353 As for pad formats, drivers store try and active rectangles for the
356 On sink pads, cropping is applied relative to the current pad format.
357 The pad format represents the image size as received by the sub-device
368 rectangle on the subdev's sink pad is scaled to the size configured
371 using ``V4L2_SEL_TGT_COMPOSE`` selection target on the same pad. If the
377 COMPOSE rectangle on the sink pad. In both sink and source pads, the
415 the sink pad towards the source pad. This is also reflected in the order
428 1. Sink pad format. The user configures the sink pad format. This format
430    pad for further processing.
432 2. Sink pad actual crop selection. The sink pad crop defines the crop
433    performed to the sink pad format.
435 3. Sink pad actual compose selection. The size of the sink pad compose
437    pad crop rectangle. The location of the compose rectangle specifies
441 4. Source pad actual crop selection. Crop on the source pad defines crop
444 5. Source pad format. The source pad format defines the output pixel
447    by the size of the source pad actual crop selection.
453 selection will refer to the sink pad format dimensions instead.
464 In the above example, the subdev supports cropping on its sink pad. To
466 pad. Now the actual crop rectangle can be set on the sink pad --- the
470 pad.
515 and only a single stream can pass through a media link and a media pad.
516 Thus each pad contains a format and selection configuration for that
519 subdev are still a single stream per pad.
523 link connecting a transmitter source pad with a sink pad on the receiver. For
526 by a media link which connects the single sensor's source pad with the receiver
527 sink pad. The stream-aware receiver will de-multiplex the streams received on
528 the its sink pad and allows to route them individually to one of its source
546 A stream ID is a media pad-local identifier for a stream. Streams IDs of
553 sub-device and a (pad, stream) pair. For sub-devices that do not support
560 formats and selections from pads to (pad, stream) pairs. Besides the
561 usual pad, also the stream ID needs to be provided for setting formats and
569 stream on a source pad, however, only a single route is allowed.
571 Any configurations of a stream within a pad, such as format or selections,
627   pad (pad 0) which carries a pixel data stream.
630   sensors (pads 0, 1), and one source pad (pad 2), which outputs two streams.
632 - Receiver in the SoC (Receiver). The receiver has a single sink pad (pad 0),
637   connected to a single source pad in the receiver.
654     * - Sink Pad/Stream
655       - Source Pad/Stream
670     * - Sink Pad/Stream
671       - Source Pad/Stream