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CEA608: no-op readability clean-up

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PiperOrigin-RevId: 256676196
This commit is contained in:
tonihei 2019-07-05 16:20:17 +01:00 committed by Toni
parent fbb76243bd
commit d66f0c51a4
1 changed files with 49 additions and 38 deletions
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87
library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea608Decoder.java
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@ -387,45 +387,27 @@ public final class Cea608Decoder extends CeaDecoder {
continue;
}
// Special North American character set.
// ccData1 - 0|0|0|1|C|0|0|1
// ccData2 - 0|0|1|1|X|X|X|X
if (((ccData1 & 0xF7) == 0x11) && ((ccData2 & 0xF0) == 0x30)) {
if (getChannel(ccData1) == selectedChannel) {
if (!updateAndVerifyCurrentChannel(ccData1)) {
// Wrong channel.
continue;
}
if (isCtrlCode(ccData1)) {
if (isSpecialChar(ccData1, ccData2)) {
// Special North American character.
currentCueBuilder.append(getSpecialChar(ccData2));
}
continue;
}
// Extended Western European character set.
// ccData1 - 0|0|0|1|C|0|1|S
// ccData2 - 0|0|1|X|X|X|X|X
if (((ccData1 & 0xF6) == 0x12) && (ccData2 & 0xE0) == 0x20) {
if (getChannel(ccData1) == selectedChannel) {
// Remove standard equivalent of the special extended char before appending new one
} else if (isExtendedWestEuropeanChar(ccData1, ccData2)) {
// Extended West European character.
// Remove standard equivalent of the special extended char before appending new one.
currentCueBuilder.backspace();
if ((ccData1 & 0x01) == 0x00) {
// Extended Spanish/Miscellaneous and French character set (S = 0).
currentCueBuilder.append(getExtendedEsFrChar(ccData2));
} else {
// Extended Portuguese and German/Danish character set (S = 1).
currentCueBuilder.append(getExtendedPtDeChar(ccData2));
}
currentCueBuilder.append(getExtendedWestEuropeanChar(ccData1, ccData2));
} else {
// Non-character control code.
handleCtrl(ccData1, ccData2, repeatedControlPossible);
}
continue;
}
// Control character.
// ccData1 - 0|0|0|X|X|X|X|X
if ((ccData1 & 0xE0) == 0x00) {
handleCtrl(ccData1, ccData2, repeatedControlPossible);
continue;
}
if (currentChannel != selectedChannel) {
continue;
}
// Basic North American character set.
currentCueBuilder.append(getChar(ccData1));
if ((ccData2 & 0xE0) != 0x00) {
@ -440,8 +422,14 @@ public final class Cea608Decoder extends CeaDecoder {
}
}
private boolean updateAndVerifyCurrentChannel(byte cc1) {
if (isCtrlCode(cc1)) {
currentChannel = getChannel(cc1);
}
return currentChannel == selectedChannel;
}
private void handleCtrl(byte cc1, byte cc2, boolean repeatedControlPossible) {
currentChannel = getChannel(cc1);
// Most control commands are sent twice in succession to ensure they are received properly. We
// don't want to process duplicate commands, so if we see the same repeatable command twice in a
// row then we ignore the second one.
@ -459,10 +447,6 @@ public final class Cea608Decoder extends CeaDecoder {
}
}
if (currentChannel != selectedChannel) {
return;
}
if (isMidrowCtrlCode(cc1, cc2)) {
handleMidrowCtrl(cc2);
} else if (isPreambleAddressCode(cc1, cc2)) {
@ -681,11 +665,33 @@ public final class Cea608Decoder extends CeaDecoder {
return (char) BASIC_CHARACTER_SET[index];
}
private static boolean isSpecialChar(byte cc1, byte cc2) {
// cc1 - 0|0|0|1|C|0|0|1
// cc2 - 0|0|1|1|X|X|X|X
return ((cc1 & 0xF7) == 0x11) && ((cc2 & 0xF0) == 0x30);
}
private static char getSpecialChar(byte ccData) {
int index = ccData & 0x0F;
return (char) SPECIAL_CHARACTER_SET[index];
}
private static boolean isExtendedWestEuropeanChar(byte cc1, byte cc2) {
// cc1 - 0|0|0|1|C|0|1|S
// cc2 - 0|0|1|X|X|X|X|X
return ((cc1 & 0xF6) == 0x12) && ((cc2 & 0xE0) == 0x20);
}
private static char getExtendedWestEuropeanChar(byte cc1, byte cc2) {
if ((cc1 & 0x01) == 0x00) {
// Extended Spanish/Miscellaneous and French character set (S = 0).
return getExtendedEsFrChar(cc2);
} else {
// Extended Portuguese and German/Danish character set (S = 1).
return getExtendedPtDeChar(cc2);
}
}
private static char getExtendedEsFrChar(byte ccData) {
int index = ccData & 0x1F;
return (char) SPECIAL_ES_FR_CHARACTER_SET[index];
@ -696,6 +702,11 @@ public final class Cea608Decoder extends CeaDecoder {
return (char) SPECIAL_PT_DE_CHARACTER_SET[index];
}
private static boolean isCtrlCode(byte cc1) {
// cc1 - 0|0|0|X|X|X|X|X
return (cc1 & 0xE0) == 0x00;
}
private static int getChannel(byte cc1) {
// cc1 - X|X|X|X|C|X|X|X
return (cc1 >> 3) & 0x1;