107 lines
3.6 KiB
C++
Executable File
107 lines
3.6 KiB
C++
Executable File
/**********
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This library is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
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This library is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
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more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this library; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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**********/
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// "liveMedia"
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// Copyright (c) 1996-2016 Live Networks, Inc. All rights reserved.
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// H.263+ Video RTP Sources
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// Implementation
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#include "H263plusVideoRTPSource.hh"
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H263plusVideoRTPSource*
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H263plusVideoRTPSource::createNew(UsageEnvironment& env, Groupsock* RTPgs,
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unsigned char rtpPayloadFormat,
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unsigned rtpTimestampFrequency) {
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return new H263plusVideoRTPSource(env, RTPgs, rtpPayloadFormat,
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rtpTimestampFrequency);
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}
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H263plusVideoRTPSource
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::H263plusVideoRTPSource(UsageEnvironment& env, Groupsock* RTPgs,
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unsigned char rtpPayloadFormat,
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unsigned rtpTimestampFrequency)
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: MultiFramedRTPSource(env, RTPgs,
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rtpPayloadFormat, rtpTimestampFrequency),
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fNumSpecialHeaders(0), fSpecialHeaderBytesLength(0) {
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}
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H263plusVideoRTPSource::~H263plusVideoRTPSource() {
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}
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Boolean H263plusVideoRTPSource
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::processSpecialHeader(BufferedPacket* packet,
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unsigned& resultSpecialHeaderSize) {
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unsigned char* headerStart = packet->data();
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unsigned packetSize = packet->dataSize();
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// The H.263+ payload header is at least 2 bytes in size.
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// Extract the known fields from the first 2 bytes:
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unsigned expectedHeaderSize = 2;
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if (packetSize < expectedHeaderSize) return False;
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//unsigned char RR = headerStart[0]>>3;
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Boolean P = (headerStart[0]&0x4) != 0;
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Boolean V = (headerStart[0]&0x2) != 0;
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unsigned char PLEN = ((headerStart[0]&0x1)<<5)|(headerStart[1]>>3);
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//unsigned char PEBIT = headerStart[1]&0x7;
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if (V) {
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// There's an extra VRC byte at the end of the header:
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++expectedHeaderSize;
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if (packetSize < expectedHeaderSize) return False;
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}
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if (PLEN > 0) {
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// There's an extra picture header at the end:
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expectedHeaderSize += PLEN;
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if (packetSize < expectedHeaderSize) return False;
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}
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fCurrentPacketBeginsFrame = P;
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if (fCurrentPacketBeginsFrame) {
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fNumSpecialHeaders = fSpecialHeaderBytesLength = 0;
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}
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// Make a copy of the special header bytes, in case a reader
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// can use them:
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unsigned bytesAvailable
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= SPECIAL_HEADER_BUFFER_SIZE - fSpecialHeaderBytesLength - 1;
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if (expectedHeaderSize <= bytesAvailable) {
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fSpecialHeaderBytes[fSpecialHeaderBytesLength++] = expectedHeaderSize;
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for (unsigned i = 0; i < expectedHeaderSize; ++i) {
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fSpecialHeaderBytes[fSpecialHeaderBytesLength++] = headerStart[i];
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}
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fPacketSizes[fNumSpecialHeaders++] = packetSize;
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}
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if (P) {
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// Prepend two zero bytes to the start of the payload proper.
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// Hack: Do this by shrinking this special header by 2 bytes:
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expectedHeaderSize -= 2;
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headerStart[expectedHeaderSize] = 0;
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headerStart[expectedHeaderSize+1] = 0;
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}
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// The RTP "M" (marker) bit indicates the last fragment of a frame:
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fCurrentPacketCompletesFrame = packet->rtpMarkerBit();
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resultSpecialHeaderSize = expectedHeaderSize;
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return True;
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}
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char const* H263plusVideoRTPSource::MIMEtype() const {
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return "video/H263-1998";
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}
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