Hi Matt and Hans,, On Wed, Nov 02, 2016 at 11:10:41PM -0700, Matt Ranostay wrote: > On Fri, Oct 28, 2016 at 7:59 PM, Matt Ranostay <matt@ranostay.consulting> wrote: > > On Fri, Oct 28, 2016 at 2:53 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > >> Hi Matt, > >> > >> On 28/10/16 22:14, Matt Ranostay wrote: > >>> > >>> So want to toss a few thoughts on adding support for thermopile > >>> devices (could be used for FLIR Lepton as well) that output pixel > >>> data. > >>> These typically aren't DMA'able devices since they are low speed > >>> (partly to limiting the functionality to be in compliance with ITAR) > >>> and data is piped over i2c/spi. > >>> > >>> My question is that there doesn't seem to be an other driver that > >>> polls frames off of a device and pushes it to the video buffer, and > >>> wanted to be sure that this doesn't currently exist somewhere. > >> > >> > >> Not anymore, but if you go back to kernel 3.6 then you'll find this driver: > >> > >> drivers/media/video/bw-qcam.c > >> > >> It was for a grayscale parallel port webcam (which explains why it was > >> removed in 3.7 :-) ), and it used polling to get the pixels. > > > > Yikes parallel port, but I'll take a look at that for some reference :) > > > So does anyone know of any software that is using V4L2_PIX_FMT_Y12 > currently? Want to test my driver but seems there isn't anything that > uses that format (ffmpeg, mplayer, etc). yavta can capture that, it doesn't convert it to anything else though. <URL:http://git.ideasonboard.org/yavta.git> > > Raw data seems correct but would like to visualize it :). Suspect I'll > need to write a test case application though > > > > > >> > >>> Also more importantly does the mailing list thinks it belongs in v4l2? > >> > >> > >> I think it fits. It's a sensor, just with a very small resolution and > >> infrared > >> instead of visible light. Agreed. > >> > >>> We already came up the opinion on the IIO list that it doesn't belong > >>> in that subsystem since pushing raw pixel data to a buffer is a bit > >>> hacky. Also could be generically written with regmap so other devices > >>> (namely FLIR Lepton) could be easily supported. > >>> > >>> Need some input for the video pixel data types, which the device we > >>> are using (see datasheet links below) is outputting pixel data in > >>> little endian 16-bit of which a 12-bits signed value is used. Does it > >>> make sense to do some basic processing on the data since greyscale is > >>> going to look weird with temperatures under 0C degrees? Namely a cold > >>> object is going to be brighter than the hottest object it could read. > >> > >> > >>> Or should a new V4L2_PIX_FMT_* be defined and processing done in > >>> software? > >> > >> > >> I would recommend that. It's no big deal, as long as the new format is > >> documented. Agreed; in general such conversion on CPU does not belong to drivers (but e.g. libv4l). > >> > >>> Another issue is how to report the scaling value of 0.25 C > >>> for each LSB of the pixels to the respecting recording application. > >> > >> > >> Probably through a read-only control, but I'm not sure. As this is the property of the format, I'd try to represent it as such. But that's another discussion... -- Kind regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
