Perform PLC for each lost packet in the FEC block

This commit is contained in:
Cameron Gutman 2021-06-03 21:03:46 -05:00
parent a8aed6b344
commit 509a17dbc3
2 changed files with 33 additions and 15 deletions

View File

@ -153,13 +153,17 @@ static bool queuePacketToLbq(PQUEUED_AUDIO_PACKET* packet) {
}
static void decodeInputData(PQUEUED_AUDIO_PACKET packet) {
PRTP_PACKET rtp;
// If the packet size is zero, this is a placeholder for a missing
// packet. Trigger packet loss concealment logic in libopus by
// invoking the decoder with a NULL buffer.
if (packet->header.size == 0) {
AudioCallbacks.decodeAndPlaySample(NULL, 0);
return;
}
rtp = (PRTP_PACKET)&packet->data[0];
PRTP_PACKET rtp = (PRTP_PACKET)&packet->data[0];
if (lastSeq != 0 && (unsigned short)(lastSeq + 1) != rtp->sequenceNumber) {
Limelog("Received OOS audio data (expected %d, but got %d)\n", lastSeq + 1, rtp->sequenceNumber);
AudioCallbacks.decodeAndPlaySample(NULL, 0);
}
lastSeq = rtp->sequenceNumber;

View File

@ -501,21 +501,31 @@ int RtpaAddPacket(PRTP_AUDIO_QUEUE queue, PRTP_PACKET packet, uint16_t length) {
PRTP_PACKET RtpaGetQueuedPacket(PRTP_AUDIO_QUEUE queue, uint16_t customHeaderLength, uint16_t* length) {
validateFecBlockState(queue);
// If we're returning audio data even with discontinuities, find the next data packet
// If we're returning audio data even with discontinuities, we'll fill in blank entries
// for packets that were lost and could not be recovered.
if (queue->blockHead != NULL && queue->blockHead->allowDiscontinuity) {
PRTPA_FEC_BLOCK nextBlock = queue->blockHead;
PRTP_PACKET lostPacket;
while (nextBlock->nextDataPacketIndex < RTPA_DATA_SHARDS) {
LC_ASSERT(nextBlock->fecHeader.baseSequenceNumber + nextBlock->nextDataPacketIndex == queue->nextRtpSequenceNumber);
if (nextBlock->marks[nextBlock->nextDataPacketIndex]) {
// This packet is missing. Skip it.
// This packet is missing. Return an empty entry to let the caller
// know to perform packet loss concealment for this frame.
lostPacket = malloc(customHeaderLength);
if (lostPacket == NULL) {
return NULL;
}
// Lost packet placeholder entries have no associated data
*length = 0;
// Move on to the next data shard
nextBlock->nextDataPacketIndex++;
queue->nextRtpSequenceNumber++;
}
else {
lostPacket = NULL;
LC_ASSERT(queueHasPacketReady(queue));
break;
}
}
// If we've read everything from this FEC block, remove and free it
@ -525,6 +535,10 @@ PRTP_PACKET RtpaGetQueuedPacket(PRTP_AUDIO_QUEUE queue, uint16_t customHeaderLen
else {
validateFecBlockState(queue);
}
if (lostPacket != NULL) {
return lostPacket;
}
}
// Return the next RTP sequence number by indexing into the most recent FEC block