void MultiFramedRTPSink::buildAndSendPacket(Boolean isFirstPacket) {
fIsFirstPacket = isFirstPacket;
// Set up the RTP header:
unsigned rtpHdr = 0x80000000; // RTP version 2; marker ('M') bit not set (by default; it can be set later)
rtpHdr |= (fRTPPayloadType<<16);
rtpHdr |= fSeqNo; // sequence number
fOutBuf->enqueueWord(rtpHdr);
// Note where the RTP timestamp will go.
// (We can't fill this in until we start packing payload frames.)
fTimestampPosition = fOutBuf->curPacketSize();
fOutBuf->skipBytes(4); // leave a hole for the timestamp
fOutBuf->enqueueWord(SSRC());
// Allow for a special, payload-format-specific header following the
// RTP header:
fSpecialHeaderPosition = fOutBuf->curPacketSize();
fSpecialHeaderSize = specialHeaderSize();
fOutBuf->skipBytes(fSpecialHeaderSize);
// Begin packing as many (complete) frames into the packet as we can:
fTotalFrameSpecificHeaderSizes = 0;
fNoFramesLeft = False;
fNumFramesUsedSoFar = 0;
packFrame();
}
Boolean MultiFramedRTPSink::isTooBigForAPacket(unsigned numBytes) const {
// Check whether a 'numBytes'-byte frame - together with a RTP header and
// (possible) special headers - would be too big for an output packet:
// (Later allow for RTP extension header!) #####
numBytes += rtpHeaderSize + specialHeaderSize() + frameSpecificHeaderSize();
return fOutBuf->isTooBigForAPacket(numBytes);
}
void AMRAudioRTPSink::doSpecialFrameHandling(unsigned fragmentationOffset,
unsigned char* frameStart,
unsigned numBytesInFrame,
struct timeval frameTimestamp,
unsigned numRemainingBytes) {
// If this is the 1st frame in the 1st packet, set the RTP 'M' (marker)
// bit (because this is considered the start of a talk spurt):
if (isFirstPacket() && isFirstFrameInPacket()) {
setMarkerBit();
}
// If this is the first frame in the packet, set the 1-byte payload
// header (using CMR 15)
if (isFirstFrameInPacket()) {
u_int8_t payloadHeader = 0xF0;
setSpecialHeaderBytes(&payloadHeader, 1, 0);
}
// Set the TOC field for the current frame, based on the "FT" and "Q"
// values from our source:
AMRAudioSource* amrSource = (AMRAudioSource*)fSource;
if (amrSource == NULL) return; // sanity check
u_int8_t toc = amrSource->lastFrameHeader();
Debug(ckite_log_message, "Last frame toc is %d\n", toc);
// Clear the "F" bit, because we're the last frame in this packet: #####
toc &=~ 0x80;
if (numFramesUsedSoFar() != specialHeaderSize() - 2)
toc |= 0x80;
setSpecialHeaderBytes(&toc, 1, 1+numFramesUsedSoFar());
// Important: Also call our base class's doSpecialFrameHandling(),
// to set the packet's timestamp:
MultiFramedRTPSink::doSpecialFrameHandling(fragmentationOffset,
frameStart, numBytesInFrame,
frameTimestamp,
numRemainingBytes);
}
