Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Ezequiel Garcia <> | Subject | [PATCH v2 05/14] media: uapi: h264: Increase size of 'first_mb_in_slice' field | Date | Thu, 6 Aug 2020 12:13:01 -0300 |
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Slice header syntax element 'first_mb_in_slice' can point to the last macroblock, currently the field can only reference 65536 macroblocks which is insufficient for 8K videos.
Although unlikely, a 8192x4320 video (where macroblocks are 16x16), would contain 138240 macroblocks on a frame.
As per the H264 specification, 'first_mb_in_slice' can be up to PicSizeInMbs - 1, so increase the size of the field to 32-bits.
Note that v4l2_ctrl_h264_slice_params struct will be modified in a follow-up commit, and so we defer its 64-bit padding.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com> --- Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 2 +- include/media/h264-ctrls.h | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index e4dec3f9b71a..141c9249d528 100644 --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst @@ -1774,7 +1774,7 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - * - __u32 - ``header_bit_size`` - - * - __u16 + * - __u32 - ``first_mb_in_slice`` - * - __u8 diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h index 54cd9bec0b23..66327ca55088 100644 --- a/include/media/h264-ctrls.h +++ b/include/media/h264-ctrls.h @@ -167,7 +167,8 @@ struct v4l2_ctrl_h264_slice_params { /* Offset in bits to slice_data() from the beginning of this slice. */ __u32 header_bit_size; - __u16 first_mb_in_slice; + __u32 first_mb_in_slice; + __u8 slice_type; __u8 pic_parameter_set_id; __u8 colour_plane_id; -- 2.27.0
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