1/**********
2This library is free software; you can redistribute it and/or modify it under
3the terms of the GNU Lesser General Public License as published by the
4Free Software Foundation; either version 3 of the License, or (at your
5option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
6
7This library is distributed in the hope that it will be useful, but WITHOUT
8ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
9FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
10more details.
11
12You should have received a copy of the GNU Lesser General Public License
13along with this library; if not, write to the Free Software Foundation, Inc.,
1451 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
15**********/
16// "liveMedia"
17// Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved.
18// VP8 Video RTP Sources
19// Implementation
20
21#include "VP8VideoRTPSource.hh"
22
23VP8VideoRTPSource*
24VP8VideoRTPSource::createNew(UsageEnvironment& env, Groupsock* RTPgs,
25 unsigned char rtpPayloadFormat,
26 unsigned rtpTimestampFrequency) {
27 return new VP8VideoRTPSource(env, RTPgs, rtpPayloadFormat,
28 rtpTimestampFrequency);
29}
30
31VP8VideoRTPSource
32::VP8VideoRTPSource(UsageEnvironment& env, Groupsock* RTPgs,
33 unsigned char rtpPayloadFormat,
34 unsigned rtpTimestampFrequency)
35 : MultiFramedRTPSource(env, RTPgs, rtpPayloadFormat, rtpTimestampFrequency) {
36}
37
38VP8VideoRTPSource::~VP8VideoRTPSource() {
39}
40
41#define incrHeader do { ++resultSpecialHeaderSize; ++headerStart; if (--packetSize == 0) return False; } while (0)
42
43Boolean VP8VideoRTPSource
44::processSpecialHeader(BufferedPacket* packet,
45 unsigned& resultSpecialHeaderSize) {
46 unsigned char* headerStart = packet->data();
47 unsigned packetSize = packet->dataSize();
48
49 // The special header is from 1 to 6 bytes long.
50 if (packetSize == 0) return False; // error
51 resultSpecialHeaderSize = 1; // unless we learn otherwise
52
53 u_int8_t const byte1 = *headerStart;
54 Boolean const X = (byte1&0x80) != 0;
55 Boolean const S = (byte1&0x10) != 0;
56 u_int8_t const PartID = byte1&0x0F;
57
58 fCurrentPacketBeginsFrame = S && PartID == 0;
59 fCurrentPacketCompletesFrame = packet->rtpMarkerBit(); // RTP header's "M" bit
60
61 if (X) {
62 incrHeader;
63
64 u_int8_t const byte2 = *headerStart;
65 Boolean const I = (byte2&0x80) != 0;
66 Boolean const L = (byte2&0x40) != 0;
67 Boolean const T = (byte2&0x20) != 0;
68 Boolean const K = (byte2&0x10) != 0;
69
70 if (I) {
71 incrHeader;
72 if ((*headerStart)&0x80) { // extension flag in the PictureID is set
73 incrHeader;
74 }
75 }
76
77 if (L) incrHeader;
78 if (T||K) incrHeader;
79 }
80
81 return True;
82}
83
84char const* VP8VideoRTPSource::MIMEtype() const {
85 return "video/VP8";
86}
87