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/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// "liveMedia"
// Copyright (c) 1996-2005 Live Networks, Inc. All rights reserved.
// H.263+ Video RTP Sources
// Implementation
#include "H263plusVideoRTPSource.hh"
H263plusVideoRTPSource*
H263plusVideoRTPSource::createNew(UsageEnvironment& env, Groupsock* RTPgs,
unsigned char rtpPayloadFormat,
unsigned rtpTimestampFrequency) {
return new H263plusVideoRTPSource(env, RTPgs, rtpPayloadFormat,
rtpTimestampFrequency);
}
H263plusVideoRTPSource
::H263plusVideoRTPSource(UsageEnvironment& env, Groupsock* RTPgs,
unsigned char rtpPayloadFormat,
unsigned rtpTimestampFrequency)
: MultiFramedRTPSource(env, RTPgs,
rtpPayloadFormat, rtpTimestampFrequency),
fNumSpecialHeaders(0), fSpecialHeaderBytesLength(0) {
}
H263plusVideoRTPSource::~H263plusVideoRTPSource() {
}
Boolean H263plusVideoRTPSource
::processSpecialHeader(BufferedPacket* packet,
unsigned& resultSpecialHeaderSize) {
unsigned char* headerStart = packet->data();
unsigned packetSize = packet->dataSize();
// The H.263+ payload header is at least 2 bytes in size.
// Extract the known fields from the first 2 bytes:
unsigned expectedHeaderSize = 2;
if (packetSize < expectedHeaderSize) return False;
//unsigned char RR = headerStart[0]>>3;
Boolean P = (headerStart[0]&0x4) != 0;
Boolean V = (headerStart[0]&0x2) != 0;
unsigned char PLEN = ((headerStart[0]&0x1)<<5)|(headerStart[1]>>3);
//unsigned char PEBIT = headerStart[1]&0x7;
if (V) {
// There's an extra VRC byte at the end of the header:
++expectedHeaderSize;
if (packetSize < expectedHeaderSize) return False;
}
if (PLEN > 0) {
// There's an extra picture header at the end:
expectedHeaderSize += PLEN;
if (packetSize < expectedHeaderSize) return False;
}
fCurrentPacketBeginsFrame = P;
if (fCurrentPacketBeginsFrame) {
fNumSpecialHeaders = fSpecialHeaderBytesLength = 0;
}
// Make a copy of the special header bytes, in case a reader
// can use them:
unsigned bytesAvailable
= SPECIAL_HEADER_BUFFER_SIZE - fSpecialHeaderBytesLength - 1;
if (expectedHeaderSize <= bytesAvailable) {
fSpecialHeaderBytes[fSpecialHeaderBytesLength++] = expectedHeaderSize;
for (unsigned i = 0; i < expectedHeaderSize; ++i) {
fSpecialHeaderBytes[fSpecialHeaderBytesLength++] = headerStart[i];
}
fPacketSizes[fNumSpecialHeaders++] = packetSize;
}
if (P) {
// Prepend two zero bytes to the start of the payload proper.
// Hack: Do this by shrinking this special header by 2 bytes:
expectedHeaderSize -= 2;
headerStart[expectedHeaderSize] = 0;
headerStart[expectedHeaderSize+1] = 0;
}
// The RTP "M" (marker) bit indicates the last fragment of a frame:
fCurrentPacketCompletesFrame = packet->rtpMarkerBit();
resultSpecialHeaderSize = expectedHeaderSize;
return True;
}
char const* H263plusVideoRTPSource::MIMEtype() const {
return "video/H263-1998";
}
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