Em Fri, 13 Dec 2019 17:04:25 +0100
Jernej Skrabec <jernej.skrabec@xxxxxxxx> escreveu:
> HEVC has a scaling matrix concept. Add support for it.
> +struct v4l2_ctrl_hevc_scaling_matrix {
> + __u8 scaling_list_4x4[6][16];
> + __u8 scaling_list_8x8[6][64];
> + __u8 scaling_list_16x16[6][64];
> + __u8 scaling_list_32x32[2][64];
> + __u8 scaling_list_dc_coef_16x16[6];
> + __u8 scaling_list_dc_coef_32x32[2];
> +};
I never looked at HEVC spec, but the above seems really weird.
Please correct me if I am wrong, but each of the above matrixes
is independent, and the driver will use just one of the above on
any specific time (for a given video output node), right?
If so, why would userspace be forced to update lots of matrixes, if would
likely use just one at a given time?
IMO, the proper way would be, instead, to use an uAPI like:
/*
* Actually, as this is uAPI, we will use a fixed size integer type, like
* unsigned int
*/
enum hevc_scaling_matrix_type {
HEVC_SCALING_MATRIX_4x4,
HEVC_SCALING_MATRIX_8x8,
...
HEVC_SCALING_MATRIX_DC_COEF_32x32,
};
struct v4l2_ctrl_hevc_scaling_matrix {
__u32 scaling_type /* as defined by enum hevc_scaling_matrix_type */
union {
__u8 scaling_list_4x4[6][16];
__u8 scaling_list_8x8[6][64];
__u8 scaling_list_16x16[6][64];
__u8 scaling_list_32x32[2][64];
__u8 scaling_list_dc_coef_16x16[6];
__u8 scaling_list_dc_coef_32x32[2];
};
};
And let the core use a default for each scaling matrix, if userspace doesn't
set it.
Cheers,
Mauro
