Better temporal filter handling.

From: Hans Verkuil <hverkuil@xs4all.nl>

Adjust temporal filter if necessary. The problem with the temporal
filter is that it works well with full resolution capturing, but
not when the capture window is scaled (the filter introduces
a ghosting effect). So if the capture window changed, and there is
no updated filter value, then the filter is set depending on whether
the new window is full resolution or not.

For full resolution a setting of 8 really improves the video
quality, especially if the original video quality is suboptimal. 

Also report VBI Format in VIDIOC_LOG_STATUS, it was missing.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

1 files changed, 22 insertions, 3 deletions

diff --git a/linux/drivers/media/video/cx2341x.c b/linux/drivers/media/video/cx2341x.c
index f4da970a0..8fc5dc0b5 100644
--- a/linux/drivers/media/video/cx2341x.c
+++ b/linux/drivers/media/video/cx2341x.c
@@ -695,7 +695,7 @@ void cx2341x_fill_defaults(struct cx2341x_mpeg_params *p)
 	.video_luma_spatial_filter_type = V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR,
 	.video_chroma_spatial_filter_type = V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR,
 	.video_temporal_filter_mode = V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL,
-	.video_temporal_filter = 0,
+	.video_temporal_filter = 8,
 	.video_median_filter_type = V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF,
 	.video_luma_median_filter_top = 255,
 	.video_luma_median_filter_bottom = 0,
@@ -735,6 +735,7 @@ int cx2341x_update(void *priv, cx2341x_mbox_func func,
 	};
 
 	int err = 0;
+	u16 temporal = new->video_temporal_filter;
 
 	cx2341x_api(priv, func, CX2341X_ENC_SET_OUTPUT_PORT, 2, new->port, 0);
 
@@ -745,6 +746,7 @@ int cx2341x_update(void *priv, cx2341x_mbox_func func,
 
 	if (old == NULL || old->width != new->width || old->height != new->height ||
 			old->video_encoding != new->video_encoding) {
+		int is_scaling;
 		u16 w = new->width;
 		u16 h = new->height;
 
@@ -754,6 +756,20 @@ int cx2341x_update(void *priv, cx2341x_mbox_func func,
 		}
 		err = cx2341x_api(priv, func, CX2341X_ENC_SET_FRAME_SIZE, 2, h, w);
 		if (err) return err;
+
+		/* Adjust temporal filter if necessary. The problem with the temporal
+		   filter is that it works well with full resolution capturing, but
+		   not when the capture window is scaled (the filter introduces
+		   a ghosting effect). So if the capture window changed, and there is
+		   no updated filter value, then the filter is set depending on whether
+		   the new window is full resolution or not.
+
+		   For full resolution a setting of 8 really improves the video
+		   quality, especially if the original video quality is suboptimal. */
+		is_scaling = new->width != 720 || new->height != (new->is_50hz ? 576 : 480);
+		if (old && old->video_temporal_filter == temporal) {
+			temporal = is_scaling ? 0 : 8;
+		}
 	}
 
 	if (old == NULL || old->stream_type != new->stream_type) {
@@ -819,9 +835,9 @@ int cx2341x_update(void *priv, cx2341x_mbox_func func,
 	}
 	if (old == NULL ||
 		old->video_spatial_filter != new->video_spatial_filter ||
-		old->video_temporal_filter != new->video_temporal_filter) {
+		old->video_temporal_filter != temporal) {
 		err = cx2341x_api(priv, func, CX2341X_ENC_SET_DNR_FILTER_PROPS, 2,
-			new->video_spatial_filter, new->video_temporal_filter);
+			new->video_spatial_filter, temporal);
 		if (err) return err;
 	}
 	if (old == NULL || old->video_temporal_decimation != new->video_temporal_decimation) {
@@ -859,6 +875,9 @@ void cx2341x_log_status(struct cx2341x_mpeg_params *p, const char *prefix)
 	printk(KERN_INFO "%s: Stream: %s\n",
 		prefix,
 		cx2341x_menu_item(p, V4L2_CID_MPEG_STREAM_TYPE));
+	printk(KERN_INFO "%s: VBI Format: %s\n",
+		prefix,
+		cx2341x_menu_item(p, V4L2_CID_MPEG_STREAM_VBI_FMT));
 
 	/* Video */
 	printk(KERN_INFO "%s: Video:  %dx%d, %d fps\n",