cta: add support for video capability data block

Signed-off-by: Simon Ser <contact@emersion.fr>

cta.c

@@ -84,6 +84,45 @@ parse_video_block(struct di_edid_cta *cta, struct di_cta_video_block *video,
 	return true;
 }
 
+static bool
+parse_video_cap_block(struct di_edid_cta *cta,
+		      struct di_cta_video_cap_block *video_cap,
+		      const uint8_t *data, size_t size)
+{
+	if (size < 1) {
+		add_failure(cta,
+			    "Video Capability Data Block: Empty Data Block with length %u.",
+			    size);
+		return false;
+	}
+
+	video_cap->selectable_ycc_quantization_range = has_bit(data[0], 7);
+	video_cap->selectable_rgb_quantization_range = has_bit(data[0], 6);
+	video_cap->pt_over_underscan = get_bit_range(data[0], 5, 4);
+	video_cap->it_over_underscan = get_bit_range(data[0], 3, 2);
+	video_cap->ce_over_underscan = get_bit_range(data[0], 1, 0);
+
+	if (!video_cap->selectable_rgb_quantization_range && cta->revision >= 3)
+		add_failure(cta,
+			    "Video Capability Data Block: Set Selectable RGB Quantization to avoid interop issues.");
+	/* TODO: add failure if selectable_ycc_quantization_range is unset,
+	 * the sink supports YCbCr formats and the revision is 3+ */
+
+	switch (video_cap->it_over_underscan) {
+	case DI_CTA_VIDEO_CAP_ALWAYS_OVERSCAN:
+		if (cta->flags.it_underscan)
+			add_failure(cta, "Video Capability Data Block: IT video formats are always overscanned, but bit 7 of Byte 3 of the CTA-861 Extension header is set to underscanned.");
+		break;
+	case DI_CTA_VIDEO_CAP_ALWAYS_UNDERSCAN:
+		if (!cta->flags.it_underscan)
+			add_failure(cta, "Video Capability Data Block: IT video formats are always underscanned, but bit 7 of Byte 3 of the CTA-861 Extension header is set to overscanned.");
+	default:
+		break;
+	}
+
+	return true;
+}
+
 static bool
 parse_colorimetry_block(struct di_edid_cta *cta,
 			struct di_cta_colorimetry_block *colorimetry,
@@ -237,6 +276,9 @@ parse_data_block(struct di_edid_cta *cta, uint8_t raw_tag, const uint8_t *data,
 		switch (extended_tag) {
 		case 0:
 			tag = DI_CTA_DATA_BLOCK_VIDEO_CAP;
+			if (!parse_video_cap_block(cta, &data_block->video_cap,
+						   data, size))
+				goto skip;
 			break;
 		case 2:
 			tag = DI_CTA_DATA_BLOCK_VESA_DISPLAY_DEVICE;
@@ -477,6 +519,15 @@ di_cta_data_block_get_hdr_static_metadata(const struct di_cta_data_block *block)
 	return &block->hdr_static_metadata.base;
 }
 
+const struct di_cta_video_cap_block *
+di_cta_data_block_get_video_cap(const struct di_cta_data_block *block)
+{
+	if (block->tag != DI_CTA_DATA_BLOCK_VIDEO_CAP) {
+		return NULL;
+	}
+	return &block->video_cap;
+}
+
 const struct di_edid_detailed_timing_def *const *
 di_edid_cta_get_detailed_timing_defs(const struct di_edid_cta *cta)
 {

di-edid-decode.c

@@ -594,6 +594,23 @@ cta_data_block_tag_name(enum di_cta_data_block_tag tag)
 	return "Unknown CTA-861 Data Block";
 }
 
+static const char *
+video_cap_over_underscan_name(enum di_cta_video_cap_over_underscan over_underscan,
+			      const char *unknown)
+{
+	switch (over_underscan) {
+	case DI_CTA_VIDEO_CAP_UNKNOWN_OVER_UNDERSCAN:
+		return unknown;
+	case DI_CTA_VIDEO_CAP_ALWAYS_OVERSCAN:
+		return "Always Overscanned";
+	case DI_CTA_VIDEO_CAP_ALWAYS_UNDERSCAN:
+		return "Always Underscanned";
+	case DI_CTA_VIDEO_CAP_BOTH_OVER_UNDERSCAN:
+		return "Supports both over- and underscan";
+	}
+	abort();
+}
+
 static void
 print_cta(const struct di_edid_cta *cta)
 {
@@ -602,6 +619,7 @@ print_cta(const struct di_edid_cta *cta)
 	const struct di_cta_data_block *data_block;
 	enum di_cta_data_block_tag data_block_tag;
 	const struct di_cta_svd *const *svds;
+	const struct di_cta_video_cap_block *video_cap;
 	const struct di_cta_colorimetry_block *colorimetry;
 	const struct di_cta_hdr_static_metadata_block *hdr_static_metadata;
 	size_t i;
@@ -636,6 +654,24 @@ print_cta(const struct di_edid_cta *cta)
 			svds = di_cta_data_block_get_svds(data_block);
 			printf_cta_svds(svds);
 			break;
+		case DI_CTA_DATA_BLOCK_VIDEO_CAP:
+			video_cap = di_cta_data_block_get_video_cap(data_block);
+			printf("    YCbCr quantization: %s\n",
+			       video_cap->selectable_ycc_quantization_range ?
+			       "Selectable (via AVI YQ)" : "No Data");
+			printf("    RGB quantization: %s\n",
+			       video_cap->selectable_ycc_quantization_range ?
+			       "Selectable (via AVI Q)" : "No Data");
+			printf("    PT scan behavior: %s\n",
+			       video_cap_over_underscan_name(video_cap->pt_over_underscan,
+							     "No Data"));
+			printf("    IT scan behavior: %s\n",
+			       video_cap_over_underscan_name(video_cap->it_over_underscan,
+							     "IT video formats not supported"));
+			printf("    CE scan behavior: %s\n",
+			       video_cap_over_underscan_name(video_cap->ce_over_underscan,
+							     "CE video formats not supported"));
+			break;
 		case DI_CTA_DATA_BLOCK_COLORIMETRY:
 			colorimetry = di_cta_data_block_get_colorimetry(data_block);
 			if (colorimetry->xvycc_601)

include/cta.h

@@ -59,6 +59,8 @@ struct di_cta_data_block {
 
 	/* Used for DI_CTA_DATA_BLOCK_VIDEO */
 	struct di_cta_video_block video;
+	/* Used for DI_CTA_DATA_BLOCK_VIDEO_CAP */
+	struct di_cta_video_cap_block video_cap;
 	/* Used for DI_CTA_DATA_BLOCK_COLORIMETRY */
 	struct di_cta_colorimetry_block colorimetry;
 	/* Used for DI_CTA_DATA_BLOCK_HDR_STATIC_METADATA */

include/libdisplay-info/cta.h

@@ -117,6 +117,45 @@ enum di_cta_data_block_tag {
 enum di_cta_data_block_tag
 di_cta_data_block_get_tag(const struct di_cta_data_block *block);
 
+/**
+ * Over- and underscan capability.
+ */
+enum di_cta_video_cap_over_underscan {
+	/* No data */
+	DI_CTA_VIDEO_CAP_UNKNOWN_OVER_UNDERSCAN = 0x00,
+	/* Always overscanned */
+	DI_CTA_VIDEO_CAP_ALWAYS_OVERSCAN = 0x01,
+	/* Always underscanned */
+	DI_CTA_VIDEO_CAP_ALWAYS_UNDERSCAN = 0x02,
+	/* Supports both over- and underscan */
+	DI_CTA_VIDEO_CAP_BOTH_OVER_UNDERSCAN = 0x03,
+};
+
+/**
+ * Video capability data block (VCDB), defined in section 7.5.6.
+ */
+struct di_cta_video_cap_block {
+	/* If set to true, YCC quantization range is selectable (via AVI YQ). */
+	bool selectable_ycc_quantization_range;
+	/* If set to true, RGB quantization range is selectable (via AVI Q). */
+	bool selectable_rgb_quantization_range;
+	/* Overscan/underscan behavior for PT video formats (if set to unknown,
+	 * use the IT/CE behavior) */
+	enum di_cta_video_cap_over_underscan pt_over_underscan;
+	/* Overscan/underscan behavior for IT video formats */
+	enum di_cta_video_cap_over_underscan it_over_underscan;
+	/* Overscan/underscan behavior for CE video formats */
+	enum di_cta_video_cap_over_underscan ce_over_underscan;
+};
+
+/**
+ * Get the video capabilities from a CTA data block.
+ *
+ * Returns NULL if the data block tag is not DI_CTA_DATA_BLOCK_VIDEO_CAP.
+ */
+const struct di_cta_video_cap_block *
+di_cta_data_block_get_video_cap(const struct di_cta_data_block *block);
+
 /**
  * CTA colorimetry data block, defined in section 7.5.5.
  */

test/data/hp-5dq99aa-hdmi.diff

@@ -23,7 +23,7 @@
    Detailed Timing Descriptors:
      DTD 1:  2560x1440   59.950550 Hz  16:9     88.787 kHz    241.500000 MHz (597 mm x 339 mm)
                   Hfront   48 Hsync  32 Hback   80 Hpol P
-@@ -51,32 +51,16 @@
+@@ -51,32 +51,21 @@
    Supports YCbCr 4:2:2
    Native detailed modes: 1
    Video Data Block:
@@ -52,11 +52,11 @@
 +    VIC  17
 +    VIC   1
    Video Capability Data Block:
--    YCbCr quantization: No Data
+     YCbCr quantization: No Data
--    RGB quantization: No Data
+     RGB quantization: No Data
--    PT scan behavior: Always Underscanned
+     PT scan behavior: Always Underscanned
--    IT scan behavior: Always Underscanned
+     IT scan behavior: Always Underscanned
--    CE scan behavior: Supports both over- and underscan
+     CE scan behavior: Supports both over- and underscan
 -  Vendor-Specific Data Block (AMD), OUI 00-00-1A:
 -    Version: 1.1
 -    Minimum Refresh Rate: 46 Hz
@@ -65,7 +65,7 @@
    Colorimetry Data Block:
      BT2020cYCC
      BT2020YCC
-@@ -104,20 +88,8 @@
+@@ -104,20 +93,12 @@
      DTD 5:  1920x1080   74.972503 Hz  16:9     83.894 kHz    174.500000 MHz (597 mm x 339 mm)
                   Hfront   48 Hsync  32 Hback   80 Hpol P
                   Vfront    3 Vsync   5 Vback   31 Vpol N
@@ -81,10 +81,9 @@
 -  Colorimetry Data Block: Set the sRGB colorimetry bit to avoid interop issues.
 -  Display Product Serial Number is set, so the Serial Number in the Base EDID should be 0.
 -
--Failures:
+ Failures:
+ 
+ Block 1, CTA-861 Extension Block:
+   Video Capability Data Block: Set Selectable RGB Quantization to avoid interop issues.
 -
--Block 1, CTA-861 Extension Block:
+ EDID conformity: FAIL
--  Video Capability Data Block: Set Selectable RGB Quantization to avoid interop issues.
--
--EDID conformity: FAIL
-+EDID conformity: PASS