media: uapi: mpeg2: Split sequence and picture parameters

Typically, bitstreams are composed of a sequence header,
followed by a number of picture header and picture coding extension
headers. Each picture can be composed of a number of slices.

Let's split the MPEG-2 uAPI to follow these semantics more closely,
allowing more usage flexibility. Having these controls split up
allows applications to set a sequence control at the beginning
of a sequence, and then set a picture control for each frame.

While here add padding fields where needed, and document
the uAPI header thoroughly.

Note that the V4L2_CTRL_TYPE_{} defines had to be moved because
it clashes with existing ones. This is not really an issue
since they will be re-defined when the controls are moved
out of staging.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Tested-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

2 files changed, 86 insertions, 23 deletions

diff --git a/include/media/mpeg2-ctrls.h b/include/media/mpeg2-ctrls.h
index d3190979d574..b4a6aa16d4c0 100644
--- a/include/media/mpeg2-ctrls.h
+++ b/include/media/mpeg2-ctrls.h
@@ -13,24 +13,44 @@
 
 #define V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS		(V4L2_CID_CODEC_BASE+250)
 #define V4L2_CID_MPEG_VIDEO_MPEG2_QUANTISATION		(V4L2_CID_CODEC_BASE+251)
+#define V4L2_CID_MPEG_VIDEO_MPEG2_SEQUENCE		(V4L2_CID_CODEC_BASE+252)
+#define V4L2_CID_MPEG_VIDEO_MPEG2_PICTURE		(V4L2_CID_CODEC_BASE+253)
 
 /* enum v4l2_ctrl_type type values */
-#define V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS 0x0103
-#define	V4L2_CTRL_TYPE_MPEG2_QUANTISATION 0x0104
+#define V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS 0x0130
+#define V4L2_CTRL_TYPE_MPEG2_QUANTISATION 0x0131
+#define V4L2_CTRL_TYPE_MPEG2_SEQUENCE 0x0132
+#define V4L2_CTRL_TYPE_MPEG2_PICTURE 0x0133
 
-#define V4L2_MPEG2_SEQ_FLAG_PROGRESSIVE		0x0001
+#define V4L2_MPEG2_SEQ_FLAG_PROGRESSIVE		0x01
 
-struct v4l2_mpeg2_sequence {
-	/* ISO/IEC 13818-2, ITU-T Rec. H.262: Sequence header */
+/**
+ * struct v4l2_ctrl_mpeg2_sequence - MPEG-2 sequence header
+ *
+ * All the members on this structure match the sequence header and sequence
+ * extension syntaxes as specified by the MPEG-2 specification.
+ *
+ * Fields horizontal_size, vertical_size and vbv_buffer_size are a
+ * combination of respective _value and extension syntax elements,
+ * as described in section 6.3.3 "Sequence header".
+ *
+ * @horizontal_size: combination of elements horizontal_size_value and
+ * horizontal_size_extension.
+ * @vertical_size: combination of elements vertical_size_value and
+ * vertical_size_extension.
+ * @vbv_buffer_size: combination of elements vbv_buffer_size_value and
+ * vbv_buffer_size_extension.
+ * @profile_and_level_indication: see MPEG-2 specification.
+ * @chroma_format: see MPEG-2 specification.
+ * @flags: see V4L2_MPEG2_SEQ_FLAG_{}.
+ */
+struct v4l2_ctrl_mpeg2_sequence {
 	__u16	horizontal_size;
 	__u16	vertical_size;
 	__u32	vbv_buffer_size;
-
-	/* ISO/IEC 13818-2, ITU-T Rec. H.262: Sequence extension */
 	__u16	profile_and_level_indication;
 	__u8	chroma_format;
-
-	__u32	flags;
+	__u8	flags;
 };
 
 #define V4L2_MPEG2_PIC_CODING_TYPE_I			1
@@ -51,33 +71,72 @@ struct v4l2_mpeg2_sequence {
 #define V4L2_MPEG2_PIC_FLAG_REPEAT_FIRST		0x0040
 #define V4L2_MPEG2_PIC_FLAG_PROGRESSIVE			0x0080
 
-struct v4l2_mpeg2_picture {
-	/* ISO/IEC 13818-2, ITU-T Rec. H.262: Picture header */
-	__u8	picture_coding_type;
-
-	/* ISO/IEC 13818-2, ITU-T Rec. H.262: Picture coding extension */
+/**
+ * struct v4l2_ctrl_mpeg2_picture - MPEG-2 picture header
+ *
+ * All the members on this structure match the picture header and picture
+ * coding extension syntaxes as specified by the MPEG-2 specification.
+ *
+ * @flags: see V4L2_MPEG2_PIC_FLAG_{}.
+ * @f_code[2][2]: see MPEG-2 specification.
+ * @picture_coding_type: see MPEG-2 specification.
+ * @picture_structure: see V4L2_MPEG2_PIC_{}_FIELD.
+ * @intra_dc_precision: see MPEG-2 specification.
+ * @reserved: padding field. Should be zeroed by applications.
+ */
+struct v4l2_ctrl_mpeg2_picture {
+	__u32	flags;
 	__u8	f_code[2][2];
-	__u8	intra_dc_precision;
+	__u8	picture_coding_type;
 	__u8	picture_structure;
-
-	__u32	flags;
+	__u8	intra_dc_precision;
+	__u8	reserved[5];
 };
 
+/**
+ * struct v4l2_ctrl_mpeg2_slice_params - MPEG-2 slice header
+ *
+ * @backward_ref_ts: timestamp of the V4L2 capture buffer to use as
+ * reference for backward prediction.
+ * @forward_ref_ts: timestamp of the V4L2 capture buffer to use as
+ * reference for forward prediction. These timestamp refers to the
+ * timestamp field in struct v4l2_buffer. Use v4l2_timeval_to_ns()
+ * to convert the struct timeval to a __u64.
+ * @quantiser_scale_code: quantiser scale integer matching an
+ * homonymous syntax element.
+ * @reserved: padding field. Should be zeroed by applications.
+ */
 struct v4l2_ctrl_mpeg2_slice_params {
 	__u32	bit_size;
 	__u32	data_bit_offset;
 	__u64	backward_ref_ts;
 	__u64	forward_ref_ts;
-
-	struct v4l2_mpeg2_sequence sequence;
-	struct v4l2_mpeg2_picture picture;
-
-	/* ISO/IEC 13818-2, ITU-T Rec. H.262: Slice */
 	__u32	quantiser_scale_code;
+	__u32	reserved;
 };
 
+/**
+ * struct v4l2_ctrl_mpeg2_quantisation - MPEG-2 quantisation
+ *
+ * Quantization matrices as specified by section 6.3.7
+ * "Quant matrix extension".
+ *
+ * @intra_quantiser_matrix: The quantisation matrix coefficients
+ * for intra-coded frames, in zigzag scanning order. It is relevant
+ * for both luma and chroma components, although it can be superseded
+ * by the chroma-specific matrix for non-4:2:0 YUV formats.
+ * @non_intra_quantiser_matrix: The quantisation matrix coefficients
+ * for non-intra-coded frames, in zigzag scanning order. It is relevant
+ * for both luma and chroma components, although it can be superseded
+ * by the chroma-specific matrix for non-4:2:0 YUV formats.
+ * @chroma_intra_quantiser_matrix: The quantisation matrix coefficients
+ * for the chominance component of intra-coded frames, in zigzag scanning
+ * order. Only relevant for 4:2:2 and 4:4:4 YUV formats.
+ * @chroma_non_intra_quantiser_matrix: The quantisation matrix coefficients
+ * for the chrominance component of non-intra-coded frames, in zigzag scanning
+ * order. Only relevant for 4:2:2 and 4:4:4 YUV formats.
+ */
 struct v4l2_ctrl_mpeg2_quantisation {
-	/* ISO/IEC 13818-2, ITU-T Rec. H.262: Quant matrix extension */
 	__u8	intra_quantiser_matrix[64];
 	__u8	non_intra_quantiser_matrix[64];
 	__u8	chroma_intra_quantiser_matrix[64];
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index a38e6bd02a6a..572ff7eb7be1 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -40,6 +40,8 @@ struct video_device;
  * @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_sequence:		Pointer to a MPEG2 sequence structure.
+ * @p_mpeg2_picture:		Pointer to a MPEG2 picture structure.
  * @p_mpeg2_slice_params:	Pointer to a MPEG2 slice parameters structure.
  * @p_mpeg2_quantisation:	Pointer to a MPEG2 quantisation data structure.
  * @p_fwht_params:		Pointer to a FWHT stateless parameters structure.
@@ -66,6 +68,8 @@ union v4l2_ctrl_ptr {
 	u16 *p_u16;
 	u32 *p_u32;
 	char *p_char;
+	struct v4l2_ctrl_mpeg2_sequence *p_mpeg2_sequence;
+	struct v4l2_ctrl_mpeg2_picture *p_mpeg2_picture;
 	struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
 	struct v4l2_ctrl_mpeg2_quantisation *p_mpeg2_quantisation;
 	struct v4l2_ctrl_fwht_params *p_fwht_params;