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Ezequiel Garcia 81bbb65f19 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>
2021-05-23 19:21:30 +02:00
arch media: ARM: dts: sama5d4: enable Hantro G1 VDEC 2021-05-19 09:51:40 +02:00
block block-5.13-2021-05-09 2021-05-09 13:25:14 -07:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto for-5.13/drivers-2021-04-27 2021-04-28 14:39:37 -07:00
Documentation media: uapi: mpeg2: rework quantisation matrices semantics 2021-05-23 19:21:30 +02:00
drivers media: uapi: mpeg2: rework quantisation matrices semantics 2021-05-23 19:21:30 +02:00
fs 3 small SMB3 chmultichannel related changesets (also for stable) 2021-05-09 13:19:29 -07:00
include media: uapi: mpeg2: rework quantisation matrices semantics 2021-05-23 19:21:30 +02:00
init Merge branch 'akpm' (patches from Andrew) 2021-05-07 00:34:51 -07:00
ipc ipc/sem.c: spelling fix 2021-05-07 00:26:34 -07:00
kernel A set of scheduler updates: 2021-05-09 13:14:34 -07:00
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Makefile Linux 5.13-rc1 2021-05-09 14:17:44 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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