Search code examples
v4l2

Where I can find example in using v4l2 codec driver

in Raspberry-Pi code, there is a s5p-jpeg codec driver.

drivers/media/platform/s5p-jpeg/jpeg-core.c

Can sombody please tell me where I can find an example of how to use it? Or any other v4l2 codec driver?

I have googled for it, but I cannot find any example which uses a v4l2 codec driver.

Solution

  • (adding another answer, since it's completely different :-))

    A "codec" API in the V4L2 specs, refers to hardware codecs. such a codec is a device that has the following features:

    • the hardware codec shows up as a /dev/videoX device

    • it has a video input, where you're userland application can send a video-stream - e.g. containing JPEG-encoded video frames - to, so it has the V4L2_CAP_VIDEO_OUTPUT capability and

    • it has a video output, where you're userland application can read a video-stream - e.g. containing the uncompressed frames - from, so it also has the V4L2_CAP_VIDEO_CAPTURE capability.

    There are numerous applications that can write video to a v4l2 OUTPUT device, here are a few that i know of:

    afaik, these application don't have any specific code to deal with "v4l2 codec devices", but can write to/read from v4l2 devices, which is all that you should need.

    Also check the v4l-utils.git: Look in utils/v4l2-ctl/v4l2-ctl-streaming.cpp