Em Fri, 10 Mar 2017 17:00:59 -0800
Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx> escreveu:
> On 3/10/2017 12:53 PM, Mauro Carvalho Chehab wrote:
> > The libv4lconvert part of libv4l was meant to provide a common
> > place to handle weird proprietary formats. With time, we also
> > added support to other standard formats, in order to help
> > V4L2 applications that are not performance sensitive to support
> > all V4L2 formats.
> >
> > Yet, the hole idea is to let userspace to decide to implement
> > their own format conversion code when it needs either more
> > performance or more quality than what libv4lconvert provides.
> >
> > In other words, applications should have the right to decide
> > between using a libv4lconvert emulated format or to implement
> > the decoding themselves for non-proprietary formats,
> > as this may have significative performance impact.
> >
> > At the application side, deciding between them is just a matter
> > of looking at the V4L2_FMT_FLAG_EMULATED flag.
> >
> > Yet, we don't want to have a miriad of format converters
> > everywhere for the proprietary formats, like V4L2_PIX_FMT_KONICA420,
> > V4L2_PIX_FMT_SPCA501, etc. So, let's offer only the emulated
> > variant for those weird stuff.
> >
> > So, this patch changes the libv4lconvert behavior, for
> > all non-proprietary formats, including Bayer, to offer both
> > the original format and the emulated ones.
> >
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
> > ---
> > lib/libv4lconvert/libv4lconvert.c | 17 ++++++++---------
> > 1 file changed, 8 insertions(+), 9 deletions(-)
> >
> > diff --git a/lib/libv4lconvert/libv4lconvert.c b/lib/libv4lconvert/libv4lconvert.c
> > index da718918b030..d87d6b91a838 100644
> > --- a/lib/libv4lconvert/libv4lconvert.c
> > +++ b/lib/libv4lconvert/libv4lconvert.c
> > @@ -118,10 +118,10 @@ static const struct v4lconvert_pixfmt supported_src_pixfmts[] = {
> > { V4L2_PIX_FMT_OV511, 0, 7, 7, 1 },
> > { V4L2_PIX_FMT_OV518, 0, 7, 7, 1 },
> > /* uncompressed bayer */
> > - { V4L2_PIX_FMT_SBGGR8, 8, 8, 8, 1 },
> > - { V4L2_PIX_FMT_SGBRG8, 8, 8, 8, 1 },
> > - { V4L2_PIX_FMT_SGRBG8, 8, 8, 8, 1 },
> > - { V4L2_PIX_FMT_SRGGB8, 8, 8, 8, 1 },
> > + { V4L2_PIX_FMT_SBGGR8, 8, 8, 8, 0 },
> > + { V4L2_PIX_FMT_SGBRG8, 8, 8, 8, 0 },
> > + { V4L2_PIX_FMT_SGRBG8, 8, 8, 8, 0 },
> > + { V4L2_PIX_FMT_SRGGB8, 8, 8, 8, 0 },
> > { V4L2_PIX_FMT_STV0680, 8, 8, 8, 1 },
> > /* compressed bayer */
> > { V4L2_PIX_FMT_SPCA561, 0, 9, 9, 1 },
> > @@ -178,7 +178,7 @@ struct v4lconvert_data *v4lconvert_create_with_dev_ops(int fd, void *dev_ops_pri
> > /* This keeps tracks of devices which have only formats for which apps
> > most likely will need conversion and we can thus safely add software
> > processing controls without a performance impact. */
>
>
> The bottom part seems unwanted.
> Before, if any source format did not need conversion then always_needs_conversion = 0
> else always_needs_conversion = 1
>
> Now
> if any source format needs conversion then always_needs_conversion = 1
> else always_needs_conversion = 0
Hmm... you're right. I dropped that part at "PATH v2".
I also added a patch improving the documentation about this logic,
with is not too clear, IMHO.
Thanks,
Mauro
