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SubjectRe: [PATCH v2 05/10] media: v4l: Add definitions for MPEG2 frame format and header metadata
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On Thu, 2018-04-19 at 17:45 +0200, Paul Kocialkowski wrote:
> Stateless video decoding engines require both the MPEG slices and
> associated metadata from the video stream in order to decode frames.
>
> This introduces definitions for a new pixel format, describing buffers
> with MPEG2 slice data, as well as a control structure for passing the
> frame header (metadata) to drivers.

While working on this, I came accross Hugues Fruchet's series that also
adds similar definitions for parsed MPEG2 metadata:
https://patchwork.kernel.org/patch/9704707/

Since that version made it to a v6, I will take the time to read the
discussion and see what needs to be changed in my proposal, so that we
can avoid discussing the same points over a year later.

This will most likely not make it to the next revision of the driver
series, so I will keep the format/controls definitions in their v2 state
(despite all the useful comments received) and take the time to properly
rework things in a future revision.

Cheers,

Paul

> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> Signed-off-by: Florent Revest <florent.revest@free-electrons.com>
> ---
> drivers/media/v4l2-core/v4l2-ctrls.c | 10 ++++++++++
> drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
> include/uapi/linux/v4l2-controls.h | 26 ++++++++++++++++++++++++++
> include/uapi/linux/videodev2.h | 3 +++
> 4 files changed, 40 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> b/drivers/media/v4l2-core/v4l2-ctrls.c
> index ba05a8b9a095..fcdc12b9a9e0 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -761,6 +761,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE: re
> turn "Vertical MV Search Range";
> case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER: re
> turn "Repeat Sequence Header";
> case V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME: retu
> rn "Force Key Frame";
> + case V4L2_CID_MPEG_VIDEO_MPEG2_FRAME_HDR: retu
> rn "MPEG2 Frame Header";
>
> /* VPX controls */
> case V4L2_CID_MPEG_VIDEO_VPX_NUM_PARTITIONS: r
> eturn "VPX Number of Partitions";
> @@ -1152,6 +1153,9 @@ void v4l2_ctrl_fill(u32 id, const char **name,
> enum v4l2_ctrl_type *type,
> case V4L2_CID_RDS_TX_ALT_FREQS:
> *type = V4L2_CTRL_TYPE_U32;
> break;
> + case V4L2_CID_MPEG_VIDEO_MPEG2_FRAME_HDR:
> + *type = V4L2_CTRL_TYPE_MPEG2_FRAME_HDR;
> + break;
> default:
> *type = V4L2_CTRL_TYPE_INTEGER;
> break;
> @@ -1472,6 +1476,9 @@ static int std_validate(const struct v4l2_ctrl
> *ctrl, u32 idx,
> return -ERANGE;
> return 0;
>
> + case V4L2_CTRL_TYPE_MPEG2_FRAME_HDR:
> + return 0;
> +
> default:
> return -EINVAL;
> }
> @@ -2046,6 +2053,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct
> v4l2_ctrl_handler *hdl,
> case V4L2_CTRL_TYPE_U32:
> elem_size = sizeof(u32);
> break;
> + case V4L2_CTRL_TYPE_MPEG2_FRAME_HDR:
> + elem_size = sizeof(struct v4l2_ctrl_mpeg2_frame_hdr);
> + break;
> default:
> if (type < V4L2_CTRL_COMPOUND_TYPES)
> elem_size = sizeof(s32);
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c
> b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 468c3c65362d..8070203da5d2 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1273,6 +1273,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc
> *fmt)
> case V4L2_PIX_FMT_VC1_ANNEX_L: descr = "VC-1
> (SMPTE 412M Annex L)"; break;
> case V4L2_PIX_FMT_VP8: descr = "VP8";
> break;
> case V4L2_PIX_FMT_VP9: descr = "VP9";
> break;
> + case V4L2_PIX_FMT_MPEG2_FRAME: descr = "MPEG2
> Frame"; break;
> case V4L2_PIX_FMT_CPIA1: descr = "GSPCA CPiA
> YUV"; break;
> case V4L2_PIX_FMT_WNVA: descr =
> "WNVA"; break;
> case V4L2_PIX_FMT_SN9C10X: descr = "GSPCA
> SN9C10X"; break;
> diff --git a/include/uapi/linux/v4l2-controls.h
> b/include/uapi/linux/v4l2-controls.h
> index cbbb750d87d1..8431b2a540c7 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -557,6 +557,8 @@ enum v4l2_mpeg_video_mpeg4_profile {
> };
> #define V4L2_CID_MPEG_VIDEO_MPEG4_QPEL (V4L2_CID_MPEG_
> BASE+407)
>
> +#define
> V4L2_CID_MPEG_VIDEO_MPEG2_FRAME_HDR (V4L2_CID_MPEG_BASE+450)
> +
> /* Control IDs for VP8 streams
> * Although VP8 is not part of MPEG we add these controls to the
> MPEG class
> * as that class is already handling other video compression
> standards
> @@ -985,4 +987,28 @@ enum v4l2_detect_md_mode {
> #define V4L2_CID_DETECT_MD_THRESHOLD_GRID (V4L2_CID_DETECT_CLA
> SS_BASE + 3)
> #define V4L2_CID_DETECT_MD_REGION_GRID (V4L2_CID_DETEC
> T_CLASS_BASE + 4)
>
> +struct v4l2_ctrl_mpeg2_frame_hdr {
> + __u32 slice_len;
> + __u32 slice_pos;
> + enum { MPEG1, MPEG2 } type;
> +
> + __u16 width;
> + __u16 height;
> +
> + enum { PCT_I = 1, PCT_P, PCT_B, PCT_D } picture_coding_type;
> + __u8 f_code[2][2];
> +
> + __u8 intra_dc_precision;
> + __u8 picture_structure;
> + __u8 top_field_first;
> + __u8 frame_pred_frame_dct;
> + __u8 concealment_motion_vectors;
> + __u8 q_scale_type;
> + __u8 intra_vlc_format;
> + __u8 alternate_scan;
> +
> + __u8 backward_ref_index;
> + __u8 forward_ref_index;
> +};
> +
> #endif
> diff --git a/include/uapi/linux/videodev2.h
> b/include/uapi/linux/videodev2.h
> index 31b5728b56e9..4b8336f7bcf0 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -635,6 +635,7 @@ struct v4l2_pix_format {
> #define V4L2_PIX_FMT_VC1_ANNEX_L v4l2_fourcc('V', 'C', '1', 'L') /*
> SMPTE 421M Annex L compliant stream */
> #define V4L2_PIX_FMT_VP8 v4l2_fourcc('V', 'P', '8', '0') /* VP8
> */
> #define V4L2_PIX_FMT_VP9 v4l2_fourcc('V', 'P', '9', '0') /* VP9
> */
> +#define V4L2_PIX_FMT_MPEG2_FRAME v4l2_fourcc('M', 'G', '2', 'F') /*
> MPEG2 frame */
>
> /* Vendor-specific formats */
> #define V4L2_PIX_FMT_CPIA1 v4l2_fourcc('C', 'P', 'I', 'A') /*
> cpia1 YUV */
> @@ -1586,6 +1587,7 @@ struct v4l2_ext_control {
> __u8 __user *p_u8;
> __u16 __user *p_u16;
> __u32 __user *p_u32;
> + struct v4l2_ctrl_mpeg2_frame_hdr __user
> *p_mpeg2_frame_hdr;
> void __user *ptr;
> };
> } __attribute__ ((packed));
> @@ -1631,6 +1633,7 @@ enum v4l2_ctrl_type {
> V4L2_CTRL_TYPE_U8 = 0x0100,
> V4L2_CTRL_TYPE_U16 = 0x0101,
> V4L2_CTRL_TYPE_U32 = 0x0102,
> + V4L2_CTRL_TYPE_MPEG2_FRAME_HDR = 0x0109,
> };
>
> /* Used in the VIDIOC_QUERYCTRL ioctl for querying controls */
--
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering
https://bootlin.com[unhandled content-type:application/pgp-signature]
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