media: v4l: Add definitions for MPEG-2 slice format and metadata

Stateless video decoding engines require both the MPEG-2 slices and
associated metadata from the video stream in order to decode frames.

This introduces definitions for a new pixel format, describing buffers
with MPEG-2 slice data, as well as control structure sfor passing the
frame metadata to drivers.

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

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

3 files changed, 204 insertions, 2 deletions

diff --git a/Documentation/media/uapi/v4l/extended-controls.rst b/Documentation/media/uapi/v4l/extended-controls.rst
index 9f7312bf3365..65a1d873196b 100644
--- a/Documentation/media/uapi/v4l/extended-controls.rst
+++ b/Documentation/media/uapi/v4l/extended-controls.rst
@@ -1497,6 +1497,182 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
 
 
 
+.. _v4l2-mpeg-mpeg2:
+
+``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
+    Specifies the slice parameters (as extracted from the bitstream) for the
+    associated MPEG-2 slice data. This includes the necessary parameters for
+    configuring a stateless hardware decoding pipeline for MPEG-2.
+    The bitstream parameters are defined according to :ref:`mpeg2part2`.
+
+.. 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
+      - ``bit_size``
+      - Size (in bits) of the current slice data.
+    * - __u32
+      - ``data_bit_offset``
+      - Offset (in bits) to the video data in the current slice data.
+    * - struct :c:type:`v4l2_mpeg2_sequence`
+      - ``sequence``
+      - Structure with MPEG-2 sequence metadata, merging relevant fields from
+	the sequence header and sequence extension parts of the bitstream.
+    * - struct :c:type:`v4l2_mpeg2_picture`
+      - ``picture``
+      - Structure with MPEG-2 picture metadata, merging relevant fields from
+	the picture header and picture coding extension parts of the bitstream.
+    * - __u8
+      - ``quantiser_scale_code``
+      - Code used to determine the quantization scale to use for the IDCT.
+    * - __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
+	B-coded frames.
+
+.. c:type:: v4l2_mpeg2_sequence
+
+.. cssclass:: longtable
+
+.. flat-table:: struct v4l2_mpeg2_sequence
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u16
+      - ``horizontal_size``
+      - The width of the displayable part of the frame's luminance component.
+    * - __u16
+      - ``vertical_size``
+      - The height of the displayable part of the frame's luminance component.
+    * - __u32
+      - ``vbv_buffer_size``
+      - Used to calculate the required size of the video buffering verifier,
+	defined (in bits) as: 16 * 1024 * vbv_buffer_size.
+    * - __u8
+      - ``profile_and_level_indication``
+      - The current profile and level indication as extracted from the
+	bitstream.
+    * - __u8
+      - ``progressive_sequence``
+      - Indication that all the frames for the sequence are progressive instead
+	of interlaced.
+    * - __u8
+      - ``chroma_format``
+      - The chrominance sub-sampling format (1: 4:2:0, 2: 4:2:2, 3: 4:4:4).
+
+.. c:type:: v4l2_mpeg2_picture
+
+.. cssclass:: longtable
+
+.. flat-table:: struct v4l2_mpeg2_picture
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u8
+      - ``picture_coding_type``
+      - Picture coding type for the frame covered by the current slice
+	(V4L2_MPEG2_PICTURE_CODING_TYPE_I, V4L2_MPEG2_PICTURE_CODING_TYPE_P or
+	V4L2_MPEG2_PICTURE_CODING_TYPE_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, 3: 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 quantization 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
+      - ``repeat_first_field``
+      - This flag affects the decoding process of progressive frames.
+    * - __u8
+      - ``progressive_frame``
+      - Indicates whether the current frame is progressive.
+
+``V4L2_CID_MPEG_VIDEO_MPEG2_QUANTIZATION (struct)``
+    Specifies quantization matrices (as extracted from the bitstream) for the
+    associated MPEG-2 slice data.
+
+.. c:type:: v4l2_ctrl_mpeg2_quantization
+
+.. cssclass:: longtable
+
+.. flat-table:: struct v4l2_ctrl_mpeg2_quantization
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u8
+      - ``load_intra_quantiser_matrix``
+      - One bit to indicate whether to load the ``intra_quantiser_matrix`` data.
+    * - __u8
+      - ``load_non_intra_quantiser_matrix``
+      - One bit to indicate whether to load the ``non_intra_quantiser_matrix``
+	data.
+    * - __u8
+      - ``load_chroma_intra_quantiser_matrix``
+      - One bit to indicate whether to load the
+	``chroma_intra_quantiser_matrix`` data, only relevant for non-4:2:0 YUV
+	formats.
+    * - __u8
+      - ``load_chroma_non_intra_quantiser_matrix``
+      - One bit to indicate whether to load the
+	``chroma_non_intra_quantiser_matrix`` data, only relevant for non-4:2:0
+	YUV formats.
+    * - __u8
+      - ``intra_quantiser_matrix[64]``
+      - The quantization 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.
+    * - __u8
+      - ``non_intra_quantiser_matrix[64]``
+      - The quantization 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.
+    * - __u8
+      - ``chroma_intra_quantiser_matrix[64]``
+      - The quantization matrix coefficients for the chominance component of
+	intra-coded frames, in zigzag scanning order. Only relevant for
+	non-4:2:0 YUV formats.
+    * - __u8
+      - ``chroma_non_intra_quantiser_matrix[64]``
+      - The quantization matrix coefficients for the chrominance component of
+	non-intra-coded frames, in zigzag scanning order. Only relevant for
+	non-4:2:0 YUV formats.
 
 MFC 5.1 MPEG Controls
 ---------------------
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
index d04b18adac33..ba0f6c49d9bf 100644
--- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
@@ -60,6 +60,22 @@ Compressed Formats
       - ``V4L2_PIX_FMT_MPEG2``
       - 'MPG2'
       - MPEG2 video elementary stream.
+    * .. _V4L2-PIX-FMT-MPEG2-SLICE:
+
+      - ``V4L2_PIX_FMT_MPEG2_SLICE``
+      - 'MG2S'
+      - MPEG-2 parsed slice data, as extracted from the MPEG-2 bitstream.
+	This format is adapted for stateless video decoders that implement a
+	MPEG-2 pipeline (using the :ref:`codec` and :ref:`media-request-api`).
+	Metadata associated with the frame to decode is required to be passed
+	through the ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS`` control and
+	quantization matrices can optionally be specified through the
+	``V4L2_CID_MPEG_VIDEO_MPEG2_QUANTIZATION`` control.
+	See the :ref:`associated Codec Control IDs <v4l2-mpeg-mpeg2>`.
+	Exactly one output and one capture buffer must be provided for use with
+	this pixel format. The output buffer must contain the appropriate number
+	of macroblocks to decode a full corresponding frame to the matching
+	capture buffer.
     * .. _V4L2-PIX-FMT-MPEG4:
 
       - ``V4L2_PIX_FMT_MPEG4``
diff --git a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
index 5bd26e8c9a1a..258f5813f281 100644
--- a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
+++ b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
@@ -424,8 +424,18 @@ See also the examples in :ref:`control`.
       - any
       - An unsigned 32-bit valued control ranging from minimum to maximum
 	inclusive. The step value indicates the increment between values.
-
-
+    * - ``V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS``
+      - n/a
+      - n/a
+      - n/a
+      - A struct :c:type:`v4l2_ctrl_mpeg2_slice_params`, containing MPEG-2
+	slice parameters for stateless video decoders.
+    * - ``V4L2_CTRL_TYPE_MPEG2_QUANTIZATION``
+      - n/a
+      - n/a
+      - n/a
+      - A struct :c:type:`v4l2_ctrl_mpeg2_quantization`, containing MPEG-2
+	quantization matrices for stateless video decoders.
 
 .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|