uvc-gadget.git/lib, branch master

lib/mjpeg_encoder: Add an MJPEG encoder for YUV420 data

2023-01-16T15:22:38+00:00

MJPEG is an extremely useful format given its compression allows
high framerates even over limited bandwith USB connections. Add
an MJPEG encoder class that converts YUV420 data into MJPEG data.

Where a libcamera-source does not support MJPEG natively, convert
YUV420 into MJPEG if the user tries to set MJPEG format.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally

lib/stream: Add and handle new VIDEO_SOURCE_ENCODED type

2023-01-16T13:10:16+00:00

Add functions to handle a new entry into video_source_type, representing
data with an encoding step between the source and sink. When running
through this route, buffers are allocated and mmaped on both the source
and the sink, then imported to the source to be filled before being queued
to the sink.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally

lib/video-source: Add video_source_import_buffers

2023-01-16T13:10:16+00:00

We need to be able to place encoded data into the sink device's bufs.
To facilitate that add a video_source operation that allows the source
to import buffers from the sink.

Add a .import_buffers() callback so that the libcamera-source can
access a sink's buffers.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally

lib: Add video_source_type enumeration

2023-01-16T13:10:16+00:00

Add an enum to struct video_source that details the type of source
we're dealing with. This will be used to make decisions about buffer
allocation and handling in a more explicit way.

Use the video_source_type associated with a video_source to decide on
the appropriate allocation function and buffer handler at stream on time.
This is a more explicit method than relying on the presence of the
.alloc_buffers op and allows more flexibility.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally

libcamera: Add new libcamera source

2023-01-16T13:10:03+00:00

Provide the integration of a libcamera source within uvc-gadget.
This adds C++ support to the project and adds libcamera as an
optional external dependency.

Reviewed-by: Kieran Bingham 
Signed-off-by: Kieran Bingham 
Signed-off-by: Daniel Scally

slideshow-source: add slideshow source class

2022-12-06T14:42:12+00:00

The slideshow_source class is an implementation of the video_source
class that streams a set of images as video.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Paul Elder

lib/jpg-source: Constrain fps

2022-11-30T13:48:26+00:00

As written the fps output by the jpg-source is unconstrained; it will
simply fill buffers as quickly as the USB subsysem can handle them.
This is not particularly realistic and also means that the frame rates
configured (and thus expected) by the host are not being adhered to.
Use the new timer infrastructure to slow down the buffer fill operation
such that the frame rates seen match those configured by the host.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally

lib/timer: Add timer infrastructure

2022-11-30T13:48:26+00:00

Some sources simply fill the buffers passed by the USB subsystem and
return them as quickly as possible. Particularly with compressed
formats operating at superspeed this rapidly results in unrealistic
frame rates.

Add infrastructure that allows us to define a specific
framerate and introduce blocking calls that constrain those sources
to the framerates expected by the host.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally

lib: uvc: Respond to control requests with dummy values

2022-11-22T16:08:30+00:00

Without a response, the host will assume there has been an error and
throw a bunch of errors. The noise of those errors makes it difficult
to see what's going on properly, so return a dummy response that
silences the errors until the functionality is properly implemented.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

lib: uvc: Add control names in output prints

2022-11-22T16:08:30+00:00

It's easier to see what's going on at a glance when the output is
human-readable, so replace the control codes with their names.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham