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| author | Ezequiel Garcia <ezequiel@collabora.com> | 2021-04-29 16:48:10 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2021-05-23 19:21:30 +0200 |
| commit | 81bbb65f19819440b42270e1f033d9b14279540c (patch) | |
| tree | 16cb3e8d6be8ca1a76b3bc01cdcef87112717146 /include/media | |
| parent | 118f3e1562f2b15e30ed65a2718cd9ed710054b1 (diff) | |
| download | linux-81bbb65f19819440b42270e1f033d9b14279540c.tar.bz2 | |
media: uapi: mpeg2: rework quantisation matrices semantics
As stated in the MPEG-2 specification, section 6.3.7 "Quant matrix
extension":
Each quantisation matrix has a default set of values. When a
sequence_header_code is decoded all matrices shall be reset to
their default values. User defined matrices may be downloaded
and this can occur in a sequence_header() or in a
quant_matrix_extension().
The load_intra_quantiser_matrix syntax elements are transmitted
in the bitstream headers, signalling that a quantisation matrix
needs to be loaded and used for pictures transmitted afterwards
(until the matrices are reset).
This "load" semantics are implemented in the V4L2 interface
without the need of any "load" flags: passing the control
is effectively a load.
Therefore, rework the V4L2_CID_MPEG_VIDEO_MPEG2_QUANTISATION
semantics to match the MPEG-2 semantics. Quantisation matrices
values are now initialized by the V4L2 control core to their
reset default value, and applications are expected to reset
their values as specified.
The quantisation control is therefore optional, and used to
load bitstream-defined values in the quantisation matrices.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Co-developed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
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>
Diffstat (limited to 'include/media')
| -rw-r--r-- | include/media/mpeg2-ctrls.h | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/include/media/mpeg2-ctrls.h b/include/media/mpeg2-ctrls.h index b8adf3ac2c1d..8ea2c7f3a172 100644 --- a/include/media/mpeg2-ctrls.h +++ b/include/media/mpeg2-ctrls.h @@ -68,11 +68,6 @@ struct v4l2_ctrl_mpeg2_slice_params { struct v4l2_ctrl_mpeg2_quantisation { /* ISO/IEC 13818-2, ITU-T Rec. H.262: Quant matrix extension */ - __u8 load_intra_quantiser_matrix; - __u8 load_non_intra_quantiser_matrix; - __u8 load_chroma_intra_quantiser_matrix; - __u8 load_chroma_non_intra_quantiser_matrix; - __u8 intra_quantiser_matrix[64]; __u8 non_intra_quantiser_matrix[64]; __u8 chroma_intra_quantiser_matrix[64]; |