| /********** |
| 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., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2015 Live Networks, Inc. All rights reserved. |
| // MPEG-1 or MPEG-2 Video RTP Sources |
| // Implementation |
| |
| #include "MPEG1or2VideoRTPSource.hh" |
| |
| MPEG1or2VideoRTPSource* |
| MPEG1or2VideoRTPSource::createNew(UsageEnvironment& env, Groupsock* RTPgs, |
| unsigned char rtpPayloadFormat, |
| unsigned rtpTimestampFrequency) { |
| return new MPEG1or2VideoRTPSource(env, RTPgs, rtpPayloadFormat, |
| rtpTimestampFrequency); |
| } |
| |
| MPEG1or2VideoRTPSource::MPEG1or2VideoRTPSource(UsageEnvironment& env, |
| Groupsock* RTPgs, |
| unsigned char rtpPayloadFormat, |
| unsigned rtpTimestampFrequency) |
| : MultiFramedRTPSource(env, RTPgs, |
| rtpPayloadFormat, rtpTimestampFrequency){ |
| } |
| |
| MPEG1or2VideoRTPSource::~MPEG1or2VideoRTPSource() { |
| } |
| |
| Boolean MPEG1or2VideoRTPSource |
| ::processSpecialHeader(BufferedPacket* packet, |
| unsigned& resultSpecialHeaderSize) { |
| // There's a 4-byte video-specific header |
| if (packet->dataSize() < 4) return False; |
| |
| u_int32_t header = ntohl(*(u_int32_t*)(packet->data())); |
| |
| u_int32_t sBit = header&0x00002000; // sequence-header-present |
| u_int32_t bBit = header&0x00001000; // beginning-of-slice |
| u_int32_t eBit = header&0x00000800; // end-of-slice |
| |
| fCurrentPacketBeginsFrame = (sBit|bBit) != 0; |
| fCurrentPacketCompletesFrame = ((sBit != 0) && (bBit == 0)) || (eBit != 0); |
| |
| resultSpecialHeaderSize = 4; |
| return True; |
| } |
| |
| Boolean MPEG1or2VideoRTPSource |
| ::packetIsUsableInJitterCalculation(unsigned char* packet, |
| unsigned packetSize) { |
| // There's a 4-byte video-specific header |
| if (packetSize < 4) return False; |
| |
| // Extract the "Picture-Type" field from this, to determine whether |
| // this packet can be used in jitter calculations: |
| unsigned header = ntohl(*(u_int32_t*)packet); |
| |
| unsigned short pictureType = (header>>8)&0x7; |
| if (pictureType == 1) { // an I frame |
| return True; |
| } else { // a P, B, D, or other unknown frame type |
| return False; |
| } |
| } |
| |
| char const* MPEG1or2VideoRTPSource::MIMEtype() const { |
| return "video/MPEG"; |
| } |
| |