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
Seems like it should be 2 separate patches even if I'm wrong.
> - int always_needs_conversion = 1;
> + int always_needs_conversion = 0;
>
> if (!data) {
> fprintf(stderr, "libv4lconvert: error: out of memory!\n");
> @@ -208,10 +208,9 @@ struct v4lconvert_data *v4lconvert_create_with_dev_ops(int fd, void *dev_ops_pri
> if (j < ARRAY_SIZE(supported_src_pixfmts)) {
> data->supported_src_formats |= 1ULL << j;
> v4lconvert_get_framesizes(data, fmt.pixelformat, j);
> - if (!supported_src_pixfmts[j].needs_conversion)
> - always_needs_conversion = 0;
> - } else
> - always_needs_conversion = 0;
> + if (supported_src_pixfmts[j].needs_conversion)
> + always_needs_conversion = 1;
> + }
> }
>
> data->no_formats = i;
>
