[PATCH v5 15/22] media: v4l: Add definitions for MPEG2 slice format and header metadata

Paul Kocialkowski
2018-07-10T08:01:07Z

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.

This is based on work from both Florent Revest and Hugues Fruchet.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>
---
.../media/uapi/v4l/extended-controls.rst | 74 +++++++++++++++++++
.../media/uapi/v4l/pixfmt-compressed.rst | 5 ++
drivers/media/v4l2-core/v4l2-ctrls.c | 44 +++++++++++
drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
include/media/v4l2-ctrls.h | 16 ++--
include/uapi/linux/v4l2-controls.h | 30 ++++++++
include/uapi/linux/videodev2.h | 3 +
7 files changed, 166 insertions(+), 7 deletions(-)

diff --git a/Documentation/media/uapi/v4l/extended-controls.rst b/Documentation/media/uapi/v4l/extended-controls.rst
index 9f7312bf3365..ef301122a14d 100644
--- a/Documentation/media/uapi/v4l/extended-controls.rst
+++ b/Documentation/media/uapi/v4l/extended-controls.rst
@@ -1497,6 +1497,80 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -

+.. _v4l2-mpeg-mpeg2:
+
+``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
+ Specifies the slice parameters (also known as slice header) for an
+ associated MPEG-2 slice data. This includes all the necessary
+ parameters for configuring a hardware decoder pipeline for MPEG-2.
+
+.. tabularcolumns:: |p{2.0cm}|p{4.0cm}|p{11.0cm}|
+
+.. c:type:: v4l2_ctrl_mpeg2_slice_params
+
+.. cssclass:: longtable
+
+.. flat-table:: struct v4l2_ctrl_mpeg2_slice_params
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - __u32
+ - ``slice_len``
+ - Length (in bits) of the current slice data.
+ * - __u32
+ - ``slice_pos``
+ - Position (in bits) of the current slice data, relative to the
+ frame start.
+ * - __u16
+ - ``width``
+ - Width of the corresponding output frame for the current slice.
+ * - __u16
+ - ``height``
+ - Height of the corresponding output frame for the current slice.
+ * - __u8
+ - ``slice_type``
+ - Picture coding type for the frame covered by the current slice
+ (V4L2_MPEG2_SLICE_TYPE_I, V4L2_MPEG2_SLICE_TYPE_P or
+ V4L2_MPEG2_SLICE_PCT_B).
+ * - __u8
+ - ``f_code[2][2]``
+ - Motion vector codes.
+ * - __u8
+ - ``intra_dc_precision``
+ - Precision of Discrete Cosine transform (0: 8 bits precision,
+ 1: 9 bits precision, 2: 10 bits precision, 11: 11 bits precision).
+ * - __u8
+ - ``picture_structure``
+ - Picture structure (1: interlaced top field,
+ 2: interlaced bottom field, 3: progressive frame).
+ * - __u8
+ - ``top_field_first``
+ - If set to 1 and interlaced stream, top field is output first.
+ * - __u8
+ - ``frame_pred_frame_dct``
+ - If set to 1, only frame-DCT and frame prediction are used.
+ * - __u8
+ - ``concealment_motion_vectors``
+ - If set to 1, motion vectors are coded for intra macroblocks.
+ * - __u8
+ - ``q_scale_type``
+ - This flag affects the inverse quantisation process.
+ * - __u8
+ - ``intra_vlc_format``
+ - This flag affects the decoding of transform coefficient data.
+ * - __u8
+ - ``alternate_scan``
+ - This flag affects the decoding of transform coefficient data.
+ * - __u8
+ - ``backward_ref_index``
+ - Index for the V4L2 buffer to use as backward reference, used with
+ B-coded and P-coded frames.
+ * - __u8
+ - ``forward_ref_index``
+ - Index for the V4L2 buffer to use as forward reference, used with
+ P-coded frames.
+ * - :cspan:`2`

MFC 5.1 MPEG Controls
---------------------
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
index abec03937bb3..4e73f62b5163 100644
--- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
@@ -60,6 +60,11 @@ Compressed Formats
- ``V4L2_PIX_FMT_MPEG2``
- 'MPG2'
- MPEG2 video elementary stream.
+ * .. _V4L2-PIX-FMT-MPEG2-SLICE:
+
+ - ``V4L2_PIX_FMT_MPEG2_SLICE``
+ - 'MG2S'
+ - MPEG2 parsed slice data, as extracted from the MPEG2 bitstream.
* .. _V4L2-PIX-FMT-MPEG4:

- ``V4L2_PIX_FMT_MPEG4``
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 3610dce3a4f8..eedbd4df25ce 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -844,6 +844,7 @@ const char *v4l2_ctrl_get_name(u32 id)
case V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE: return "Vertical MV Search Range";
case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER: return "Repeat Sequence Header";
case V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME: return "Force Key Frame";
+ case V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS: return "MPEG2 Slice Header";

/* VPX controls */
case V4L2_CID_MPEG_VIDEO_VPX_NUM_PARTITIONS: return "VPX Number of Partitions";
@@ -1292,6 +1293,9 @@ 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_SLICE_PARAMS:
+ *type = V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS;
+ break;
default:
*type = V4L2_CTRL_TYPE_INTEGER;
break;
@@ -1550,6 +1554,7 @@ static void std_log(const struct v4l2_ctrl *ctrl)
static int std_validate(const struct v4l2_ctrl *ctrl, u32 idx,
union v4l2_ctrl_ptr ptr)
{
+ struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
size_t len;
u64 offset;
s64 val;
@@ -1612,6 +1617,42 @@ static int std_validate(const struct v4l2_ctrl *ctrl, u32 idx,
return -ERANGE;
return 0;

+ case V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS:
+ p_mpeg2_slice_params = ptr.p;
+
+ switch (p_mpeg2_slice_params->intra_dc_precision) {
+ case 0: /* 8 bits */
+ case 1: /* 9 bits */
+ case 11: /* 11 bits */
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ switch (p_mpeg2_slice_params->picture_structure) {
+ case 1: /* interlaced top field */
+ case 2: /* interlaced bottom field */
+ case 3: /* progressive */
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ switch (p_mpeg2_slice_params->slice_type) {
+ case V4L2_MPEG2_SLICE_TYPE_I:
+ case V4L2_MPEG2_SLICE_TYPE_P:
+ case V4L2_MPEG2_SLICE_TYPE_B:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (p_mpeg2_slice_params->backward_ref_index > VIDEO_MAX_FRAME ||
+ p_mpeg2_slice_params->forward_ref_index > VIDEO_MAX_FRAME)
+ return -EINVAL;
+
+ return 0;
+
default:
return -EINVAL;
}
@@ -2186,6 +2227,9 @@ 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_SLICE_PARAMS:
+ elem_size = sizeof(struct v4l2_ctrl_mpeg2_slice_params);
+ 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 44fc0102221f..68e914b83a03 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1304,6 +1304,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
case V4L2_PIX_FMT_H263: descr = "H.263"; break;
case V4L2_PIX_FMT_MPEG1: descr = "MPEG-1 ES"; break;
case V4L2_PIX_FMT_MPEG2: descr = "MPEG-2 ES"; break;
+ case V4L2_PIX_FMT_MPEG2_SLICE: descr = "MPEG-2 parsed slice data"; break;
case V4L2_PIX_FMT_MPEG4: descr = "MPEG-4 part 2 ES"; break;
case V4L2_PIX_FMT_XVID: descr = "Xvid"; break;
case V4L2_PIX_FMT_VC1_ANNEX_G: descr = "VC-1 (SMPTE 412M Annex G)"; break;
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 34ee3167d7dd..8dfa22d70f8c 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -35,13 +35,14 @@ struct poll_table_struct;

/**
* union v4l2_ctrl_ptr - A pointer to a control value.
- * @p_s32: Pointer to a 32-bit signed value.
- * @p_s64: Pointer to a 64-bit signed value.
- * @p_u8: Pointer to a 8-bit unsigned value.
- * @p_u16: Pointer to a 16-bit unsigned value.
- * @p_u32: Pointer to a 32-bit unsigned value.
- * @p_char: Pointer to a string.
- * @p: Pointer to a compound value.
+ * @p_s32: Pointer to a 32-bit signed value.
+ * @p_s64: Pointer to a 64-bit signed value.
+ * @p_u8: Pointer to a 8-bit unsigned value.
+ * @p_u16: Pointer to a 16-bit unsigned value.
+ * @p_u32: Pointer to a 32-bit unsigned value.
+ * @p_char: Pointer to a string.
+ * @p_mpeg2_slice_params: Pointer to a MPEG2 slice parameters structure.
+ * @p: Pointer to a compound value.
*/
union v4l2_ctrl_ptr {
s32 *p_s32;
@@ -50,6 +51,7 @@ union v4l2_ctrl_ptr {
u16 *p_u16;
u32 *p_u32;
char *p_char;
+ struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
void *p;
};

diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index e4ee10ee917d..bbcab3d65f55 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_SLICE_PARAMS (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
@@ -1092,4 +1094,32 @@ enum v4l2_detect_md_mode {
#define V4L2_CID_DETECT_MD_THRESHOLD_GRID (V4L2_CID_DETECT_CLASS_BASE + 3)
#define V4L2_CID_DETECT_MD_REGION_GRID (V4L2_CID_DETECT_CLASS_BASE + 4)

+#define V4L2_MPEG2_SLICE_TYPE_I 1
+#define V4L2_MPEG2_SLICE_TYPE_P 2
+#define V4L2_MPEG2_SLICE_TYPE_B 3
+#define V4L2_MPEG2_SLICE_TYPE_D 4
+
+struct v4l2_ctrl_mpeg2_slice_params {
+ __u32 slice_len;
+ __u32 slice_pos;
+
+ __u16 width;
+ __u16 height;
+
+ __u8 slice_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 1f6c4b52baae..bbfe95e3fba8 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -629,6 +629,7 @@ struct v4l2_pix_format {
#define V4L2_PIX_FMT_H263 v4l2_fourcc('H', '2', '6', '3') /* H263 */
#define V4L2_PIX_FMT_MPEG1 v4l2_fourcc('M', 'P', 'G', '1') /* MPEG-1 ES */
#define V4L2_PIX_FMT_MPEG2 v4l2_fourcc('M', 'P', 'G', '2') /* MPEG-2 ES */
+#define V4L2_PIX_FMT_MPEG2_SLICE v4l2_fourcc('M', 'G', '2', 'S') /* MPEG-2 parsed slice data */
#define V4L2_PIX_FMT_MPEG4 v4l2_fourcc('M', 'P', 'G', '4') /* MPEG-4 part 2 ES */
#define V4L2_PIX_FMT_XVID v4l2_fourcc('X', 'V', 'I', 'D') /* Xvid */
#define V4L2_PIX_FMT_VC1_ANNEX_G v4l2_fourcc('V', 'C', '1', 'G') /* SMPTE 421M Annex G compliant stream */
@@ -1587,6 +1588,7 @@ struct v4l2_ext_control {
__u8 __user *p_u8;
__u16 __user *p_u16;
__u32 __user *p_u32;
+ struct v4l2_ctrl_mpeg2_slice_params __user *p_mpeg2_slice_params;
void __user *ptr;
};
} __attribute__ ((packed));
@@ -1632,6 +1634,7 @@ enum v4l2_ctrl_type {
V4L2_CTRL_TYPE_U8 = 0x0100,
V4L2_CTRL_TYPE_U16 = 0x0101,
V4L2_CTRL_TYPE_U32 = 0x0102,
+ V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS = 0x0103,
};

/* Used in the VIDIOC_QUERYCTRL ioctl for querying controls */
--
2.17.1