Re: [RFC] V4L2_PIX_FMT_MJPEG vs V4L2_PIX_FMT_JPEG

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

On Monday, 1 October 2018 11:43:04 EEST Hans Verkuil wrote:
> It turns out that we have both JPEG and Motion-JPEG pixel formats defined.
> 
> Furthermore, some drivers support one, some the other and some both.
> 
> These pixelformats both mean the same.

Do they ? I thought MJPEG was JPEG using fixed Huffman tables that were not 
included in the JPEG headers.

> I propose that we settle on JPEG (since it seems to be used most often) and
> add JPEG support to those drivers that currently only use MJPEG.
> 
> We also need to update the V4L2_PIX_FMT_JPEG documentation since it just
> says TBD:
> 
> https://www.linuxtv.org/downloads/v4l-dvb-apis-new/uapi/v4l/pixfmt-compresse
> d.html
> 
> $ git grep -l V4L2_PIX_FMT_MJPEG
> drivers/media/pci/meye/meye.c
> drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
> drivers/media/platform/sti/delta/delta-cfg.h
> drivers/media/platform/sti/delta/delta-mjpeg-dec.c
> drivers/media/usb/cpia2/cpia2_v4l.c
> drivers/media/usb/go7007/go7007-driver.c
> drivers/media/usb/go7007/go7007-fw.c
> drivers/media/usb/go7007/go7007-v4l2.c
> drivers/media/usb/s2255/s2255drv.c
> drivers/media/usb/uvc/uvc_driver.c
> drivers/staging/media/zoran/zoran_driver.c
> drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
> drivers/usb/gadget/function/uvc_v4l2.c
> 
> It looks like s2255 and cpia2 support both already, so that would leave
> 8 drivers that need to be modified, uvc being the most important of the
> lot.
> 
> Any comments?

-- 
Regards,

Laurent Pinchart