| /********** |
| 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 3 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., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2020 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"; |
| } |