Improve support of SSA (V4+) PrimaryColour style

library/core/src/main/java/com/google/android/exoplayer2/text/ssa/SsaDecoder.java

@@ -308,8 +308,8 @@ public final class SsaDecoder extends SimpleSubtitleDecoder {
 
     // Apply primary color.
     if (style != null) {
-      if (style.primaryColor != SsaStyle.SSA_COLOR_UNKNOWN) {
+      if (style.primaryColor.isSet) {
-        spannableText.setSpan(new ForegroundColorSpan(style.primaryColor),
+        spannableText.setSpan(new ForegroundColorSpan(style.primaryColor.value),
             0, spannableText.length(), SpannableString.SPAN_EXCLUSIVE_EXCLUSIVE);
       }
     }

library/core/src/main/java/com/google/android/exoplayer2/text/ssa/SsaStyle.java

@@ -89,9 +89,9 @@ import java.util.regex.Pattern;
 
   public final String name;
   @SsaAlignment public final int alignment;
-  @ColorInt public int primaryColor;
+  public SsaColor primaryColor;
 
-  private SsaStyle(String name, @SsaAlignment int alignment, @ColorInt int primaryColor) {
+  private SsaStyle(String name, @SsaAlignment int alignment, SsaColor primaryColor) {
     this.name = name;
     this.alignment = alignment;
     this.primaryColor = primaryColor;
@@ -152,14 +152,33 @@ import java.util.regex.Pattern;
     }
   }
 
-  @ColorInt
+  private static SsaColor parsePrimaryColor(String primaryColorStr) {
-  private static int parsePrimaryColor(String primaryColorStr) {
     try {
-      return ColorParser.parseSsaColor(primaryColorStr);
+      return SsaColor.from(ColorParser.parseSsaColor(primaryColorStr.trim()));
     } catch (IllegalArgumentException ex) {
       Log.w(TAG, "Failed parsing color value: " + primaryColorStr);
     }
-    return SSA_COLOR_UNKNOWN;
+    return SsaColor.UNSET;
+  }
+
+  /**
+   * Represents an SSA V4+ style color in ARGB format.
+   */
+  /* package */ static final class SsaColor {
+
+    public static SsaColor UNSET = new SsaColor(0, false);
+
+    public final @ColorInt int value;
+    public final boolean isSet;
+
+    private SsaColor(@ColorInt int value, boolean isSet) {
+      this.value = value;
+      this.isSet = isSet;
+    }
+
+    public static SsaColor from(@ColorInt int value) {
+      return new SsaColor(value, true);
+    }
   }
 
   /**

library/core/src/main/java/com/google/android/exoplayer2/util/ColorParser.java

@@ -75,17 +75,35 @@ public final class ColorParser {
    */
   @ColorInt
   public static int parseSsaColor(String colorExpression) {
-    // SSA V4+ color format is &HAABBGGRR.
+    // The SSA V4+ color can be represented in hex (&HAABBGGRR) or in decimal format (byte order
-    if (colorExpression.length() != 10 || !"&H".equals(colorExpression.substring(0, 2))) {
+    // AABBGGRR) and in both cases the alpha channel's value needs to be inverted as in case of SSA
-      throw new IllegalArgumentException();
+    // the 0xFF alpha value means transparent and 0x00 means opaque which is the opposite from the
+    // @ColorInt representation.
+    int abgr;
+    try {
+      // Parse color from hex format (&HAABBGGRR).
+      if (colorExpression.startsWith("&H")) {
+        StringBuilder rgbaStringBuilder = new StringBuilder(colorExpression);
+        if (colorExpression.length() < 10) {
+          // Add leading zeros if necessary.
+          while (rgbaStringBuilder.length() != 10) {
+            rgbaStringBuilder.insert(2, "0");
+          }
+        }
+        abgr = (int) Long.parseLong(colorExpression.substring(2), 16);
+      } else {
+        // Parse color from decimal format (bytes order AABBGGRR).
+        abgr = (int) Long.parseLong(colorExpression);
+      }
+    } catch (NumberFormatException ex) {
+      throw new IllegalArgumentException(ex);
     }
-    // Convert &HAABBGGRR to #RRGGBBAA.
+    // Convert ABGR to ARGB.
-    String rgba = new StringBuilder()
+    int a = ((abgr >> 24) & 0xFF) ^ 0xFF; // Flip alpha.
-        .append(colorExpression.substring(2))
+    int b = (abgr >> 16) & 0xFF;
-        .append("#")
+    int g = (abgr >> 8) & 0xFF;
-        .reverse()
+    int r = abgr & 0xff;
-        .toString();
+    return Color.argb(a, r, g, b);
-    return parseColorInternal(rgba, true);
   }
 
   @ColorInt

library/core/src/test/java/com/google/android/exoplayer2/util/ColorParserTest.java

@@ -16,6 +16,8 @@
 package com.google.android.exoplayer2.util;
 
 import static android.graphics.Color.BLACK;
+import static android.graphics.Color.BLUE;
+import static android.graphics.Color.GREEN;
 import static android.graphics.Color.RED;
 import static android.graphics.Color.WHITE;
 import static android.graphics.Color.YELLOW;
@@ -66,9 +68,21 @@ public final class ColorParserTest {
     // Hex colors in ColorParser are RGBA, where-as {@link Color#parseColor} takes ARGB.
     assertThat(parseTtmlColor("#FFFFFF00")).isEqualTo(parseColor("#00FFFFFF"));
     assertThat(parseTtmlColor("#12345678")).isEqualTo(parseColor("#78123456"));
-    // SSA colors are in &HAABBGGRR format.
+  }
-    assertThat(parseSsaColor("&HFF0000FF")).isEqualTo(RED);
+
-    assertThat(parseSsaColor("&HFF00FFFF")).isEqualTo(YELLOW);
+  @Test
+  public void ssaColorParsing() {
+    // Hex format (&HAABBGGRR).
+    assertThat(parseSsaColor("&H000000FF")).isEqualTo(RED);
+    assertThat(parseSsaColor("&H0000FFFF")).isEqualTo(YELLOW);
+    assertThat(parseSsaColor("&H400000FF")).isEqualTo(parseColor("#BFFF0000"));
+    // Leading zeros.
+    assertThat(parseSsaColor("&HFF")).isEqualTo(RED);
+    assertThat(parseSsaColor("&HFF00")).isEqualTo(GREEN);
+    assertThat(parseSsaColor("&HFF0000")).isEqualTo(BLUE);
+    // Decimal format (AABBGGRR byte order).
+    assertThat(parseSsaColor(/*#000000FF*/"255")).isEqualTo(parseColor("#FFFF0000"));
+    assertThat(parseSsaColor(/*#FF0000FF*/"4278190335")).isEqualTo(parseColor("#00FF0000"));
   }
 
   @Test