cta: add VIC table

Add a small Python tool to extract VIC information from the spec.

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

cta.c

@@ -23,6 +23,15 @@
  */
 #define CTA_SAD_SIZE 3
 
+const struct di_cta_video_format *
+di_cta_video_format_from_vic(uint8_t vic)
+{
+	if (vic > _di_cta_video_formats_len ||
+	    _di_cta_video_formats[vic].vic == 0)
+		return NULL;
+	return &_di_cta_video_formats[vic];
+}
+
 static void
 add_failure(struct di_edid_cta *cta, const char fmt[], ...)
 {

include/cta.h

@@ -140,6 +140,9 @@ struct di_cta_data_block {
 	struct di_cta_ycbcr420_cap_map ycbcr420_cap_map;
 };
 
+extern const struct di_cta_video_format _di_cta_video_formats[];
+extern const size_t _di_cta_video_formats_len;
+
 bool
 _di_edid_cta_parse(struct di_edid_cta *cta, const uint8_t *data, size_t size,
 		   struct di_logger *logger);

include/libdisplay-info/cta.h

@@ -13,6 +13,56 @@
 #include <stdint.h>
 #include <stddef.h>
 
+/**
+ * CTA video format picture aspect ratio.
+ */
+enum di_cta_video_format_picture_aspect_ratio {
+	DI_CTA_VIDEO_FORMAT_PICTURE_ASPECT_RATIO_4_3, /* 4:3 */
+	DI_CTA_VIDEO_FORMAT_PICTURE_ASPECT_RATIO_16_9, /* 16:9 */
+	DI_CTA_VIDEO_FORMAT_PICTURE_ASPECT_RATIO_64_27, /* 64:27 */
+	DI_CTA_VIDEO_FORMAT_PICTURE_ASPECT_RATIO_256_135, /* 256:135 */
+};
+
+/**
+ * CTA video format sync pulse polarity.
+ */
+enum di_cta_video_format_sync_polarity {
+	DI_CTA_VIDEO_FORMAT_SYNC_NEGATIVE, /* Negative */
+	DI_CTA_VIDEO_FORMAT_SYNC_POSITIVE, /* Positive */
+};
+
+/**
+ * A CTA-861 video format, defined in section 4.
+ */
+struct di_cta_video_format {
+	/* Video Identification Code (VIC) */
+	uint8_t vic;
+	/* Horizontal/vertical active pixels/lines */
+	int32_t h_active, v_active;
+	/* Horizontal/vertical front porch */
+	int32_t h_front, v_front;
+	/* Horizontal/vertical sync pulse */
+	int32_t h_sync, v_sync;
+	/* Horizontal/vertical back porch */
+	int32_t h_back, v_back;
+	/* Horizontal/vertical sync pulse polarity */
+	enum di_cta_video_format_sync_polarity h_sync_polarity, v_sync_polarity;
+	/* Pixel clock in Hz */
+	int64_t pixel_clock_hz;
+	/* Whether this timing is interlaced */
+	bool interlaced;
+	/* Picture aspect ratio */
+	enum di_cta_video_format_picture_aspect_ratio picture_aspect_ratio;
+};
+
+/**
+ * Get a CTA-861 video format from a VIC.
+ *
+ * Returns NULL if the VIC is unknown.
+ */
+const struct di_cta_video_format *
+di_cta_video_format_from_vic(uint8_t vic);
+
 /**
  * EDID CTA-861 extension block.
  */

meson.build

@@ -51,6 +51,7 @@ di_lib = library(
 	'display-info',
 	[
 		'cta.c',
+		'cta-vic-table.c',
 		'cvt.c',
 		'displayid.c',
 		'dmt-table.c',

tool/gen-cta-vic.py

@@ -0,0 +1,143 @@
+#!/usr/bin/env python3
+
+import os
+import subprocess
+import sys
+
+if len(sys.argv) != 2:
+    print("usage: gen-cta-vic.py <CTA-861-H PDF>", file=sys.stderr)
+    sys.exit(1)
+in_path = sys.argv[1]
+in_basename = os.path.basename(in_path)
+
+tool_dir = os.path.dirname(os.path.realpath(__file__))
+out_path = tool_dir + "/../cta-vic-table.c"
+
+# Page numbers for CTA-861-H
+pages = {
+    "timing": (41, 43),
+    "sync": (44, 46),
+    "aspect_ratio": (55, 58),
+}
+
+def extract_pages(page_range):
+    pages = []
+    page = ""
+    cmd = ["pdftotext", "-f", str(page_range[0]), "-l", str(page_range[1]), "-layout", in_path, "-"]
+    for l in subprocess.check_output(cmd, text=True):
+        if l.startswith("\f"):
+            pages.append(page)
+            page = l[1:]
+        else:
+            page += l
+    return pages
+
+def extract_table(page):
+    lines = [l.strip() for l in page.splitlines()]
+    rows = []
+    for l in lines:
+        fields = [field.strip() for field in l.split("  ") if field != ""]
+        rows.append(fields)
+    return rows
+
+def parse_vic_list(s):
+    return [int(vic.strip()) for vic in s.split(",")]
+
+def parse_hactive(s):
+    # Some hactive pixel values have a footnote marker
+    if s == "14402" or s == "28802":
+        s = s[:-1]
+    return int(s)
+
+def parse_interlaced(s):
+    if s == "Prog":
+        return "false"
+    elif s == "Int":
+        return "true"
+    else:
+        assert(False)
+
+def parse_timing_table(page, format_table):
+    assert("Table 1 - Video Format Timings — Detailed Timing Information" in page)
+
+    for fields in extract_table(page):
+        if len(fields) != 11 or fields[0] == "VIC":
+            continue
+        for vic in parse_vic_list(fields[0]):
+            format_table[vic] = {
+                "vic": vic,
+                "h_active": parse_hactive(fields[1]),
+                "v_active": int(fields[2]),
+                "interlaced": parse_interlaced(fields[3]),
+                "pixel_clock_hz": int(float(fields[10]) * 1000 * 1000),
+            }
+
+def parse_polarity(pol):
+    if pol == "P":
+        return "POSITIVE"
+    elif pol == "N":
+        return "NEGATIVE"
+    else:
+        assert(False)
+
+def parse_sync_table(page, format_table):
+    assert("Table 2 - Video Format Timings — Detailed Sync Information" in page)
+
+    for fields in extract_table(page):
+        if len(fields) < 12:
+            continue
+        for vic in parse_vic_list(fields[0]):
+            fmt = format_table[vic]
+            fmt["h_front"] = int(fields[2])
+            fmt["h_sync"] = int(fields[3])
+            fmt["h_back"] = int(fields[4])
+            fmt["h_sync_polarity"] = "DI_CTA_VIDEO_FORMAT_SYNC_" + parse_polarity(fields[5])
+            fmt["v_front"] = int(fields[6])
+            fmt["v_sync"] = int(fields[7])
+            fmt["v_back"] = int(fields[8])
+            fmt["v_sync_polarity"] = "DI_CTA_VIDEO_FORMAT_SYNC_" + parse_polarity(fields[9])
+
+def parse_aspect_ratio_table(page, format_table):
+    assert("Table 3 - Video Formats — Video ID Code and Aspect Ratios" in page)
+
+    for fields in extract_table(page):
+        if len(fields) != 5:
+            continue
+        vic = int(fields[0])
+        fmt = format_table[vic]
+        pic_ar = fields[3]
+        if pic_ar == "64:276":
+            # 64:27 has a footnote
+            pic_ar = pic_ar[:-1]
+        fmt["picture_aspect_ratio"] = "DI_CTA_VIDEO_FORMAT_PICTURE_ASPECT_RATIO_" + pic_ar.replace(":", "_")
+
+format_table = {}
+for page in extract_pages(pages["timing"]):
+    parse_timing_table(page, format_table)
+for page in extract_pages(pages["sync"]):
+    parse_sync_table(page, format_table)
+for page in extract_pages(pages["aspect_ratio"]):
+    parse_aspect_ratio_table(page, format_table)
+
+max_vic = 0
+for vic in format_table:
+    if vic > max_vic:
+        max_vic = vic
+
+# Sanity check
+for vic in format_table:
+    fmt = format_table[vic]
+    assert("h_sync" in fmt)
+    assert("picture_aspect_ratio" in fmt)
+
+with open(out_path, "w+") as f:
+    f.write("/* DO NOT EDIT! This file has been generated by gen-cta-vic.py from {}. */\n\n".format(in_basename))
+    f.write('#include "cta.h"\n\n')
+    f.write("const struct di_cta_video_format _di_cta_video_formats[] = {\n")
+    for vic in format_table:
+        f.write("\t[{}] = {{\n".format(vic))
+        for k, v in format_table[vic].items():
+            f.write("\t\t.{} = {},\n".format(k, v))
+        f.write("\t},\n")
+    f.write("};\n\n")
+    f.write("const size_t _di_cta_video_formats_len = {};\n".format(max_vic + 1))