gen-image: Add -C argument to disable chroma averaging on output

gen-image averages consecutive chroma values when subsampling chroma
horizontally. This matches the hardware behaviour, but isn't desired to
produce test input frames in subsampled formats as otherwise the
hardware will average the values a second time in the RPF to interpolate
missing chroma components.

Add a -C argument to disable chroma averaging on output, to be used to
generate test input frames.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/src/gen-image.c b/src/gen-image.c
index 4ba8b1a..a389f77 100644
--- a/src/gen-image.c
+++ b/src/gen-image.c
@@ -92,6 +92,7 @@ struct params {
 	unsigned int alpha;
 	enum v4l2_ycbcr_encoding encoding;
 	enum v4l2_quantization quantization;
+	bool no_chroma_average;
 };
 
 struct options {
@@ -539,8 +540,14 @@ static void image_format_yuv_packed(const struct image *input, struct image *out
 		for (x = 0; x < output->width; x += 2) {
 			o_y[2*x] = idata[3*x];
 			o_y[2*x + 2] = idata[3*x + 3];
-			o_c[2*x + u_offset] = (idata[3*x + 1] + idata[3*x + 4]) / 2;
-			o_c[2*x + v_offset] = (idata[3*x + 2] + idata[3*x + 5]) / 2;
+
+			if (params->no_chroma_average) {
+				o_c[2*x + u_offset] = idata[3*x + 1];
+				o_c[2*x + v_offset] = idata[3*x + 2];
+			} else {
+				o_c[2*x + u_offset] = (idata[3*x + 1] + idata[3*x + 4]) / 2;
+				o_c[2*x + v_offset] = (idata[3*x + 2] + idata[3*x + 5]) / 2;
+			}
 		}
 
 		o_y += input->width * 2;
@@ -587,7 +594,7 @@ static void image_format_yuv_planar(const struct image *input, struct image *out
 
 	idata = input->data;
 	for (y = 0; y < output->height / ysub; ++y) {
-		if (xsub == 1) {
+		if (xsub == 1 || params->no_chroma_average) {
 			for (x = 0; x < output->width; x += xsub) {
 				o_u[x*c_stride/xsub] = idata[3*x + 1];
 				o_v[x*c_stride/xsub] = idata[3*x + 2];
@@ -1372,6 +1379,7 @@ static void usage(const char *argv0)
 	printf("			point values ([0.0 - 1.0]), fixed point values ([0-255])\n");
 	printf("			or percentages ([0%% - 100%%]). Defaults to 1.0\n");
 	printf("-c, --compose n		Compose n copies of the image offset by (50,50) over a black background\n");
+	printf("-C, --no-chroma-average	Disable chroma averaging for odd pixels on output\n");
 	printf("-e, --encoding enc	Set the YCbCr encoding method. Valid values are\n");
 	printf("			BT.601, REC.709, BT.2020 and SMPTE240M\n");
 	printf("-f, --format format	Set the output image format\n");
@@ -1416,6 +1424,7 @@ static struct option opts[] = {
 	{"histogram", 1, 0, 'H'},
 	{"in-format", 1, 0, 'i'},
 	{"lut", 1, 0, 'l'},
+	{"no-chroma-average", 1, 0, 'C'},
 	{"output", 1, 0, 'o'},
 	{"quantization", 1, 0, 'q'},
 	{"rotate", 0, 0, 'r'},
@@ -1442,7 +1451,7 @@ static int parse_args(struct options *options, int argc, char *argv[])
 	options->params.quantization = V4L2_QUANTIZATION_LIM_RANGE;
 
 	opterr = 0;
-	while ((c = getopt_long(argc, argv, "a:c:e:f:hH:i:l:L:o:q:rs:", opts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "a:c:Ce:f:hH:i:l:L:o:q:rs:", opts, NULL)) != -1) {
 
 		switch (c) {
 		case 'a': {
@@ -1477,6 +1486,10 @@ static int parse_args(struct options *options, int argc, char *argv[])
 			  }
 			  break;
 
+		case 'C':
+			  options->params.no_chroma_average = true;
+			  break;
+
 		case 'e':
 			if (!strcmp(optarg, "BT.601")) {
 				options->params.encoding = V4L2_YCBCR_ENC_601;