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This pull request is for issue#1807. Refactoring the PR #8356

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Handling the sequence number discontinuity in caption channel packet header.

The processCurrentPacket returns if the packet length does not match with the currentIndex. That assumption is wrong. As per spec the the packet can end on reception of next cc_type = 0x3.
This commit is contained in:
sneelavara 2020-12-30 17:35:44 -08:00
parent b70f08b740
commit b534097d1c
1 changed files with 12 additions and 3 deletions
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15
library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Decoder.java
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@ -145,6 +145,7 @@ public final class Cea708Decoder extends CeaDecoder {
private final ParsableByteArray ccData;
private final ParsableBitArray serviceBlockPacket;
private int lastSequenceNo = -1;
// TODO: Use isWideAspectRatio in decoding.
@SuppressWarnings({"unused", "FieldCanBeLocal"})
private final boolean isWideAspectRatio;
@ -231,6 +232,13 @@ public final class Cea708Decoder extends CeaDecoder {
finalizeCurrentPacket();
int sequenceNumber = (ccData1 & 0xC0) >> 6; // first 2 bits
if (lastSequenceNo != -1 && sequenceNumber != (lastSequenceNo + 1) % 4) {
resetCueBuilders();
Log.w(TAG, "discontinuity in sequence number detected : lastSequenceNo = " +
lastSequenceNo + " sequenceNumber = " + sequenceNumber);
}
lastSequenceNo = sequenceNumber;
int packetSize = ccData1 & 0x3F; // last 6 bits
if (packetSize == 0) {
packetSize = 64;
@ -270,10 +278,11 @@ public final class Cea708Decoder extends CeaDecoder {
@RequiresNonNull("currentDtvCcPacket")
private void processCurrentPacket() {
if (currentDtvCcPacket.currentIndex != (currentDtvCcPacket.packetSize * 2 - 1)) {
Log.w(TAG, "DtvCcPacket ended prematurely; size is " + (currentDtvCcPacket.packetSize * 2 - 1)
Log.d(TAG, "DtvCcPacket ended prematurely; size is " + (currentDtvCcPacket.packetSize * 2 - 1)
+ ", but current index is " + currentDtvCcPacket.currentIndex + " (sequence number "
+ currentDtvCcPacket.sequenceNumber + "); ignoring packet");
return;
+ currentDtvCcPacket.sequenceNumber + ");");
// This is not invalid packet. As per CEA-708 section 4.4.1.1, the Packect end can happen
// when the reception of cc_type = 0x03 (binary 11).
}
serviceBlockPacket.reset(currentDtvCcPacket.packetData, currentDtvCcPacket.currentIndex);