4 files changed, 51 insertions, 2 deletions

diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
index 1da17a2c94d7..810ae9bb6f7c 100644
--- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
+++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
@@ -2076,6 +2076,39 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
         The OUTPUT buffer must contain all slices needed to decode the
         frame. The OUTPUT buffer must also contain both fields.
 
+``V4L2_CID_MPEG_VIDEO_H264_START_CODE (enum)``
+    Specifies the H264 slice start code expected for each slice.
+    This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE
+    pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE
+    are required to set this control in order to specify the start code
+    that is expected for the buffer.
+    Drivers may expose a single or multiple start codes, depending
+    on what they can support.
+
+    .. note::
+
+       This menu control is not yet part of the public kernel API and
+       it is expected to change.
+
+.. c:type:: v4l2_mpeg_video_h264_start_code
+
+.. cssclass:: longtable
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - ``V4L2_MPEG_VIDEO_H264_START_CODE_NONE``
+      - 0
+      - Selecting this value specifies that H264 slices are passed
+        to the driver without any start code.
+    * - ``V4L2_MPEG_VIDEO_H264_START_CODE_ANNEX_B``
+      - 1
+      - Selecting this value specifies that H264 slices are expected
+        to be prefixed by Annex B start codes. According to :ref:`h264`
+        valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001.
+
 .. _v4l2-mpeg-mpeg2:
 
 ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
index d666eb51741a..493b6020107d 100644
--- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
@@ -60,8 +60,9 @@ Compressed Formats
         extracted from the H264 bitstream.  This format is adapted for
         stateless video decoders that implement an H264 pipeline
         (using the :ref:`mem2mem` and :ref:`media-request-api`).
-        This pixelformat has a modifier that must be set at least once
-        through the ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE`` control.
+        This pixelformat has two modifiers that must be set at least once
+        through the ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE``
+        and ``V4L2_CID_MPEG_VIDEO_H264_START_CODE`` controls.
         In addition, metadata associated with the frame to decode are
         required to be passed through the ``V4L2_CID_MPEG_VIDEO_H264_SPS``,
         ``V4L2_CID_MPEG_VIDEO_H264_PPS``,
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 2c67f9fc4d5b..1d8f38824631 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -407,6 +407,11 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
                 "Frame-Based",
                 NULL,
         };
+        static const char * const h264_start_code[] = {
+                "No Start Code",
+                "Annex B Start Code",
+                NULL,
+        };
         static const char * const mpeg_mpeg2_level[] = {
                 "Low",
                 "Main",
@@ -640,6 +645,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
                 return h264_fmo_map_type;
         case V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE:
                 return h264_decode_mode;
+        case V4L2_CID_MPEG_VIDEO_H264_START_CODE:
+                return h264_start_code;
         case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
                 return mpeg_mpeg2_level;
         case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
@@ -860,6 +867,7 @@ const char *v4l2_ctrl_get_name(u32 id)
         case V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS:             return "H264 Slice Parameters";
         case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:            return "H264 Decode Parameters";
         case V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE:              return "H264 Decode Mode";
+        case V4L2_CID_MPEG_VIDEO_H264_START_CODE:               return "H264 Start Code";
         case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:                   return "MPEG2 Level";
         case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:                 return "MPEG2 Profile";
         case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:              return "MPEG4 I-Frame QP Value";
@@ -1229,6 +1237,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
         case V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE:
         case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
         case V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE:
+        case V4L2_CID_MPEG_VIDEO_H264_START_CODE:
         case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
         case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
         case V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL:
diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
index 928c48c57282..ba2876a64cf6 100644
--- a/include/media/h264-ctrls.h
+++ b/include/media/h264-ctrls.h
@@ -27,6 +27,7 @@
 #define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS   (V4L2_CID_MPEG_BASE+1003)
 #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS  (V4L2_CID_MPEG_BASE+1004)
 #define V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE    (V4L2_CID_MPEG_BASE+1005)
+#define V4L2_CID_MPEG_VIDEO_H264_START_CODE     (V4L2_CID_MPEG_BASE+1006)
 
 /* enum v4l2_ctrl_type type values */
 #define V4L2_CTRL_TYPE_H264_SPS                 0x0110
@@ -40,6 +41,11 @@ enum v4l2_mpeg_video_h264_decode_mode {
         V4L2_MPEG_VIDEO_H264_DECODE_MODE_FRAME_BASED,
 };
 
+enum v4l2_mpeg_video_h264_start_code {
+        V4L2_MPEG_VIDEO_H264_START_CODE_NONE,
+        V4L2_MPEG_VIDEO_H264_START_CODE_ANNEX_B,
+};
+
 #define V4L2_H264_SPS_CONSTRAINT_SET0_FLAG                      0x01
 #define V4L2_H264_SPS_CONSTRAINT_SET1_FLAG                      0x02
 #define V4L2_H264_SPS_CONSTRAINT_SET2_FLAG                      0x04