From 89091e12464ace837bb72c5d20173c069481afd2 Mon Sep 17 00:00:00 2001
From: Michael Tretter <m.tretter@pengutronix.de>
Date: Wed, 8 Sep 2021 14:03:51 +0100
Subject: media: allegro: correctly scale the bit rate in SPS

The bit rate in the SPS can be scaled by an exponent, which allows to
reduce the number of bits in the SPS in case of high bit rates.

The driver did not scale the bitrate, but used a scaling exponent of 0.
Fix this by properly calculating the scaling factor and writing the bit
rate as value and scaling factor into the SPS.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/media/platform/allegro-dvt/allegro-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'drivers')

diff --git a/drivers/media/platform/allegro-dvt/allegro-core.c b/drivers/media/platform/allegro-dvt/allegro-core.c
index 52924ce142cc..777cbc526ae3 100644
--- a/drivers/media/platform/allegro-dvt/allegro-core.c
+++ b/drivers/media/platform/allegro-dvt/allegro-core.c
@@ -1639,8 +1639,9 @@ static ssize_t allegro_h264_write_sps(struct allegro_channel *channel,
 	sps->vui.nal_hrd_parameters_present_flag = 0;
 	sps->vui.vcl_hrd_parameters_present_flag = 1;
 	sps->vui.vcl_hrd_parameters.cpb_cnt_minus1 = 0;
-	sps->vui.vcl_hrd_parameters.bit_rate_scale = 0;
 	/* See Rec. ITU-T H.264 (04/2017) p. 410 E-53 */
+	sps->vui.vcl_hrd_parameters.bit_rate_scale =
+		ffs(channel->bitrate_peak) - 6;
 	sps->vui.vcl_hrd_parameters.bit_rate_value_minus1[0] =
 		channel->bitrate_peak / (1 << (6 + sps->vui.vcl_hrd_parameters.bit_rate_scale)) - 1;
 	/* See Rec. ITU-T H.264 (04/2017) p. 410 E-54 */
-- 
cgit v1.2.3-70-g09d2