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>

1 files changed, 2 insertions, 36 deletions

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c b/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
index 459f71679a4f..e3154f631858 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
@@ -13,30 +13,6 @@
 #include "cedrus_hw.h"
 #include "cedrus_regs.h"
 
-/* Default MPEG-2 quantisation coefficients, from the specification. */
-
-static const u8 intra_quantisation_matrix_default[64] = {
-	8,  16, 16, 19, 16, 19, 22, 22,
-	22, 22, 22, 22, 26, 24, 26, 27,
-	27, 27, 26, 26, 26, 26, 27, 27,
-	27, 29, 29, 29, 34, 34, 34, 29,
-	29, 29, 27, 27, 29, 29, 32, 32,
-	34, 34, 37, 38, 37, 35, 35, 34,
-	35, 38, 38, 40, 40, 40, 48, 48,
-	46, 46, 56, 56, 58, 69, 69, 83
-};
-
-static const u8 non_intra_quantisation_matrix_default[64] = {
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16,
-	16, 16, 16, 16, 16, 16, 16, 16
-};
-
 static enum cedrus_irq_status cedrus_mpeg2_irq_status(struct cedrus_ctx *ctx)
 {
 	struct cedrus_dev *dev = ctx->dev;
@@ -99,12 +75,7 @@ static void cedrus_mpeg2_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
 	cedrus_engine_enable(ctx, CEDRUS_CODEC_MPEG2);
 
 	/* Set intra quantisation matrix. */
-
-	if (quantisation && quantisation->load_intra_quantiser_matrix)
-		matrix = quantisation->intra_quantiser_matrix;
-	else
-		matrix = intra_quantisation_matrix_default;
-
+	matrix = quantisation->intra_quantiser_matrix;
 	for (i = 0; i < 64; i++) {
 		reg = VE_DEC_MPEG_IQMINPUT_WEIGHT(i, matrix[i]);
 		reg |= VE_DEC_MPEG_IQMINPUT_FLAG_INTRA;
@@ -113,12 +84,7 @@ static void cedrus_mpeg2_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
 	}
 
 	/* Set non-intra quantisation matrix. */
-
-	if (quantisation && quantisation->load_non_intra_quantiser_matrix)
-		matrix = quantisation->non_intra_quantiser_matrix;
-	else
-		matrix = non_intra_quantisation_matrix_default;
-
+	matrix = quantisation->non_intra_quantiser_matrix;
 	for (i = 0; i < 64; i++) {
 		reg = VE_DEC_MPEG_IQMINPUT_WEIGHT(i, matrix[i]);
 		reg |= VE_DEC_MPEG_IQMINPUT_FLAG_NON_INTRA;