On 09/13/18 13:29, Oleksandr Andrushchenko wrote: > Hi, all! > > Is there a way in V4L2 to get number of planes from fourcc code > > or specifically I need number of planes for a given pixel format > > expressed as V4L2_PIX_FMT_* value. Sadly not. It's part of the documentation for the formats, but there is no naming scheme through which you can deduce this or even helper functions for it. I think the main reason why this never happened is that drivers tend to have custom code for this anyway. I have proposed in the past that some of this information is exposed via VIDIOC_ENUM_FMT, but it never got traction. > I know that DRM has such a helper [1], but I am not quite sure > > if I can call it with V4L2_PIX_FMT_* as argument to get what I need. > > I am a bit confused here because there are different definitions > > for DRM [2] and V4L2 [3]. I know. Each subsystem has traditionally been assigning fourccs independently. In all fairness, this seems to be the case for fourccs throughout the whole industry. Regards, Hans > > Thank you, > > Oleksandr > > [1] > https://elixir.bootlin.com/linux/v4.19-rc3/source/drivers/gpu/drm/drm_fourcc.c#L199 > > [2] > https://elixir.bootlin.com/linux/v4.19-rc3/source/include/uapi/drm/drm_fourcc.h > > [3] > https://elixir.bootlin.com/linux/v4.19-rc3/source/include/uapi/linux/videodev2.h >
