Fix Cea608Decoder handling of service switch commands in field 2

From ANSI-CTA-608-E R-2014 section 8.4:
> When closed captioning is used on line 21, field 2, it shall conform
> to all of the applicable specifications and recommended practices as
> defined for field 1 services with the following differences:
> 1. The non-printing character of the miscellaneous control-character
>    pairs that fall in the range of 0x14, 0x20 to 0x14, 0x2F in field 1,
>    shall be replaced with 0x15, 0x20 to 0x15, 0x2F when used in field
>    2.
> 2. The non-printing character of the miscellaneous control-character
>    pairs that fall in the range of 0x1C, 0x20 to 0x1C, 0x2F in field
>    1, shall be replaced with 0x1D, 0x20 to 0x1D, 0x2F when used in
>    field 2.

This basically means that `cc1=0x15` in field 2 should be interpreted as
`cc1=0x14` in field 1, and same for `0x1D -> 0x1C`.

The `isMiscCode`  method above already handles this by ignoring the LSB
(the only difference between `0x14` and `0x15`, and `0x1C` and `0x1D`)
by AND-ing with `0xF6` instead of `0xF7`. This change uses the same
trick in `isServiceSwitchCommand`.

Issue: google/ExoPlayer#10666
#minor-release
PiperOrigin-RevId: 483927506

RELEASENOTES.md

@@ -54,6 +54,9 @@ Release notes
         a non-empty but invalid license URL.
     *   Fix `setMediaDrmSession failed: session not opened` error when switching
         between DRM schemes in a playlist (e.g. Widevine to ClearKey).
+*   Text:
+    *   CEA-608: Ensure service switch commands on field 2 are handled correctly
+        ([#10666](https://github.com/google/ExoPlayer/issues/10666)).
 *   DASH:
     *   Parse `EventStream.presentationTimeOffset` from manifests
         ([#10460](https://github.com/google/ExoPlayer/issues/10460)).

libraries/extractor/src/main/java/androidx/media3/extractor/text/cea/Cea608Decoder.java

@@ -874,8 +874,8 @@ private static boolean isXdsControlCode(byte cc1) {
   }
 
   private static boolean isServiceSwitchCommand(byte cc1) {
-    // cc1 - 0|0|0|1|C|1|0|0
-    return (cc1 & 0xF7) == 0x14;
+    // cc1 - 0|0|0|1|C|1|0|F
+    return (cc1 & 0xF6) == 0x14;
   }
 
   private static final class CueBuilder {

libraries/extractor/src/test/java/androidx/media3/extractor/text/cea/Cea608DecoderTest.java

@@ -255,6 +255,65 @@ public void onlySelectedChannelIsUsed() throws Exception {
     assertThat(getOnlyCue(fifthSubtitle).text.toString()).isEqualTo("test subtitle");
   }
 
+  @Test
+  public void serviceSwitchOnField1Handled() throws Exception {
+    Cea608Decoder decoder =
+        new Cea608Decoder(
+            MimeTypes.APPLICATION_CEA608,
+            /* accessibilityChannel= */ 1, // field 1, channel 1
+            Cea608Decoder.MIN_DATA_CHANNEL_TIMEOUT_MS);
+    // field 1 (0xFC header): 'test' then service switch
+    // field 2 (0xFD header): 'wrong!'
+    byte[] sample1 =
+        Bytes.concat(
+            // 'paint on' control character
+            createPacket(0xFC, 0x14, 0x29),
+            createPacket(0xFD, 0x15, 0x29),
+            createPacket(0xFC, 't', 'e'),
+            createPacket(0xFD, 'w', 'r'),
+            createPacket(0xFC, 's', 't'),
+            createPacket(0xFD, 'o', 'n'),
+            // Enter TEXT service
+            createPacket(0xFC, 0x14, 0x2A),
+            createPacket(0xFD, 'g', '!'),
+            createPacket(0xFC, 'X', 'X'),
+            createPacket(0xFD, 0x0, 0x0));
+
+    Subtitle firstSubtitle = checkNotNull(decodeSampleAndCopyResult(decoder, sample1));
+
+    assertThat(getOnlyCue(firstSubtitle).text.toString()).isEqualTo("test");
+  }
+
+  // https://github.com/google/ExoPlayer/issues/10666
+  @Test
+  public void serviceSwitchOnField2Handled() throws Exception {
+    Cea608Decoder decoder =
+        new Cea608Decoder(
+            MimeTypes.APPLICATION_CEA608,
+            /* accessibilityChannel= */ 3, // field 2, channel 1
+            Cea608Decoder.MIN_DATA_CHANNEL_TIMEOUT_MS);
+    // field 1 (0xFC header): 'wrong!'
+    // field 2 (0xFD header): 'test' then service switch
+    byte[] sample1 =
+        Bytes.concat(
+            // 'paint on' control character
+            createPacket(0xFC, 0x14, 0x29),
+            createPacket(0xFD, 0x15, 0x29),
+            createPacket(0xFC, 'w', 'r'),
+            createPacket(0xFD, 't', 'e'),
+            createPacket(0xFC, 'o', 'n'),
+            createPacket(0xFD, 's', 't'),
+            createPacket(0xFC, 'g', '!'),
+            // Enter TEXT service
+            createPacket(0xFD, 0x15, 0x2A),
+            createPacket(0xFC, 0x0, 0x0),
+            createPacket(0xFD, 'X', 'X'));
+
+    Subtitle firstSubtitle = checkNotNull(decodeSampleAndCopyResult(decoder, sample1));
+
+    assertThat(getOnlyCue(firstSubtitle).text.toString()).isEqualTo("test");
+  }
+
   private static byte[] createPacket(int header, int cc1, int cc2) {
     return new byte[] {
       UnsignedBytes.checkedCast(header),