From 4f43ac0cb228064cf6a253275ec1ecdab30c62f0 Mon Sep 17 00:00:00 2001 From: Lars Gjesse Kjellberg Date: Mon, 25 Sep 2006 23:44:06 -0300 Subject: [PATCH] V4L/DVB (4681): Cx88: fix analog capture notch filter This patch changes the setting of the cx2388x notch filter to match that of the video capture sample frequency, removing some annoying interference lines THAT would appear when capturing composite video. This has been tested in PAL and NTSC TV norms. It sets the Y/C separation luma notch filter, which removes the chroma signal from the luma signal when using a composite input. The luma notch filter operates at the video decoder's frequency, not the ADC's frequency or at the frequency of the scaled video. Y/C separation happens after the sample rate converter, before video scaling. The datasheet provides plots of the filter response for three _video decoder_ frequencies, 4x Fsc, square pixel, and ccir601. These are the same three frequencies for the notch filter control. It seems pretty clear that this filter should be set based on the video decoder frequency. The cx88 driver always uses a video decoder frequency of 4xFsc. Signed-off-by: Lars Gjesse Kjellberg Signed-off-by: Trent Piepho Signed-off-by: Michael Krufky Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/cx88/cx88-core.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/media/video/cx88/cx88-core.c b/drivers/media/video/cx88/cx88-core.c index f379ede3049a..241cabfadeeb 100644 --- a/drivers/media/video/cx88/cx88-core.c +++ b/drivers/media/video/cx88/cx88-core.c @@ -660,9 +660,7 @@ static unsigned int inline norm_fsc8(struct cx88_tvnorm *norm) static unsigned int inline norm_notchfilter(struct cx88_tvnorm *norm) { - return (norm->id & V4L2_STD_625_50) - ? HLNotchFilter135PAL - : HLNotchFilter135NTSC; + return HLNotchFilter4xFsc; } static unsigned int inline norm_htotal(struct cx88_tvnorm *norm) -- 2.20.1