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Extend support of 608 captions in SEI messages

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Issue:#3816

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=185124378
This commit is contained in:
aquilescanta 2018-02-09 03:57:13 -08:00 committed by Oliver Woodman
parent 6aad066d51
commit d274ca6750
1 changed files with 42 additions and 50 deletions
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92
library/core/src/main/java/com/google/android/exoplayer2/text/cea/CeaUtil.java
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@ -19,18 +19,19 @@ import android.util.Log;
import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.extractor.TrackOutput;
import com.google.android.exoplayer2.util.ParsableByteArray;
import com.google.android.exoplayer2.util.Util;
/**
* Utility methods for handling CEA-608/708 messages.
*/
/** Utility methods for handling CEA-608/708 messages. Defined in A/53 Part 4:2009. */
public final class CeaUtil {
private static final String TAG = "CeaUtil";
private static final int PAYLOAD_TYPE_CC = 4;
private static final int COUNTRY_CODE = 0xB5;
private static final int PROVIDER_CODE = 0x31;
private static final int USER_ID = 0x47413934; // "GA94"
private static final int PROVIDER_CODE_ATSC = 0x31;
private static final int PROVIDER_CODE_DIRECTV = 0x2F;
private static final int USER_ID_GA94 = Util.getIntegerCodeForString("GA94");
private static final int USER_ID_DTG1 = Util.getIntegerCodeForString("DTG1");
private static final int USER_DATA_TYPE_CODE = 0x3;
/**
@ -46,33 +47,49 @@ public final class CeaUtil {
while (seiBuffer.bytesLeft() > 1 /* last byte will be rbsp_trailing_bits */) {
int payloadType = readNon255TerminatedValue(seiBuffer);
int payloadSize = readNon255TerminatedValue(seiBuffer);
int nextPayloadPosition = seiBuffer.getPosition() + payloadSize;
// Process the payload.
if (payloadSize == -1 || payloadSize > seiBuffer.bytesLeft()) {
// This might occur if we're trying to read an encrypted SEI NAL unit.
Log.w(TAG, "Skipping remainder of malformed SEI NAL unit.");
seiBuffer.setPosition(seiBuffer.limit());
} else if (isSeiMessageCea608(payloadType, payloadSize, seiBuffer)) {
// Ignore country_code (1) + provider_code (2) + user_identifier (4)
// + user_data_type_code (1).
seiBuffer.skipBytes(8);
// Ignore first three bits: reserved (1) + process_cc_data_flag (1) + zero_bit (1).
int ccCount = seiBuffer.readUnsignedByte() & 0x1F;
// Ignore em_data (1)
seiBuffer.skipBytes(1);
// Each data packet consists of 24 bits: marker bits (5) + cc_valid (1) + cc_type (2)
// + cc_data_1 (8) + cc_data_2 (8).
int sampleLength = ccCount * 3;
int sampleStartPosition = seiBuffer.getPosition();
for (TrackOutput output : outputs) {
seiBuffer.setPosition(sampleStartPosition);
output.sampleData(seiBuffer, sampleLength);
output.sampleMetadata(presentationTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleLength, 0, null);
} else if (payloadType == PAYLOAD_TYPE_CC && payloadSize >= 8) {
int countryCode = seiBuffer.readUnsignedByte();
int providerCode = seiBuffer.readUnsignedShort();
int userIdentifier = 0;
if (providerCode == PROVIDER_CODE_ATSC) {
userIdentifier = seiBuffer.readInt();
}
int userDataTypeCode = seiBuffer.readUnsignedByte();
if (providerCode == PROVIDER_CODE_DIRECTV) {
seiBuffer.skipBytes(1); // user_data_length.
}
boolean messageIsSupportedCeaCaption =
countryCode == COUNTRY_CODE
&& (providerCode == PROVIDER_CODE_ATSC || providerCode == PROVIDER_CODE_DIRECTV)
&& userDataTypeCode == USER_DATA_TYPE_CODE;
if (providerCode == PROVIDER_CODE_ATSC) {
messageIsSupportedCeaCaption &=
userIdentifier == USER_ID_GA94 || userIdentifier == USER_ID_DTG1;
}
if (messageIsSupportedCeaCaption) {
// Ignore first three bits: reserved (1) + process_cc_data_flag (1) + zero_bit (1).
int ccCount = seiBuffer.readUnsignedByte() & 0x1F;
// Ignore em_data (1)
seiBuffer.skipBytes(1);
// Each data packet consists of 24 bits: marker bits (5) + cc_valid (1) + cc_type (2)
// + cc_data_1 (8) + cc_data_2 (8).
int sampleLength = ccCount * 3;
int sampleStartPosition = seiBuffer.getPosition();
for (TrackOutput output : outputs) {
seiBuffer.setPosition(sampleStartPosition);
output.sampleData(seiBuffer, sampleLength);
output.sampleMetadata(
presentationTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleLength, 0, null);
}
}
// Ignore trailing information in SEI, if any.
seiBuffer.skipBytes(payloadSize - (10 + ccCount * 3));
} else {
seiBuffer.skipBytes(payloadSize);
}
seiBuffer.setPosition(nextPayloadPosition);
}
}
@ -97,31 +114,6 @@ public final class CeaUtil {
return value;
}
/**
* Inspects an sei message to determine whether it contains CEA-608.
* <p>
* The position of {@code payload} is left unchanged.
*
* @param payloadType The payload type of the message.
* @param payloadLength The length of the payload.
* @param payload A {@link ParsableByteArray} containing the payload.
* @return Whether the sei message contains CEA-608.
*/
private static boolean isSeiMessageCea608(int payloadType, int payloadLength,
ParsableByteArray payload) {
if (payloadType != PAYLOAD_TYPE_CC || payloadLength < 8) {
return false;
}
int startPosition = payload.getPosition();
int countryCode = payload.readUnsignedByte();
int providerCode = payload.readUnsignedShort();
int userIdentifier = payload.readInt();
int userDataTypeCode = payload.readUnsignedByte();
payload.setPosition(startPosition);
return countryCode == COUNTRY_CODE && providerCode == PROVIDER_CODE
&& userIdentifier == USER_ID && userDataTypeCode == USER_DATA_TYPE_CODE;
}
private CeaUtil() {}
}