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1 /* | |
2 * Copyright 2015 The WebRTC Project Authors. All rights reserved. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license | |
5 * that can be found in the LICENSE file in the root of the source | |
6 * tree. An additional intellectual property rights grant can be found | |
7 * in the file PATENTS. All contributing project authors may | |
8 * be found in the AUTHORS file in the root of the source tree. | |
9 */ | |
10 | |
11 #import "ARDSDPUtils.h" | |
12 | |
13 #import "WebRTC/RTCLogging.h" | |
14 #import "WebRTC/RTCSessionDescription.h" | |
15 | |
16 @implementation ARDSDPUtils | |
17 | |
18 + (RTCSessionDescription *) | |
19 descriptionForDescription:(RTCSessionDescription *)description | |
20 preferredVideoCodec:(NSString *)codec { | |
21 NSString *sdpString = description.sdp; | |
22 NSString *lineSeparator = @"\n"; | |
23 NSString *mLineSeparator = @" "; | |
24 // Copied from PeerConnectionClient.java. | |
25 // TODO(tkchin): Move this to a shared C++ file. | |
26 NSMutableArray *lines = | |
27 [NSMutableArray arrayWithArray: | |
28 [sdpString componentsSeparatedByString:lineSeparator]]; | |
29 NSInteger mLineIndex = -1; | |
30 NSString *codecRtpMap = nil; | |
31 // a=rtpmap:<payload type> <encoding name>/<clock rate> | |
32 // [/<encoding parameters>] | |
33 NSString *pattern = | |
34 [NSString stringWithFormat:@"^a=rtpmap:(\\d+) %@(/\\d+)+[\r]?$", codec]; | |
35 NSRegularExpression *regex = | |
36 [NSRegularExpression regularExpressionWithPattern:pattern | |
37 options:0 | |
38 error:nil]; | |
39 for (NSInteger i = 0; (i < lines.count) && (mLineIndex == -1 || !codecRtpMap); | |
40 ++i) { | |
41 NSString *line = lines[i]; | |
42 if ([line hasPrefix:@"m=video"]) { | |
43 mLineIndex = i; | |
44 continue; | |
45 } | |
46 NSTextCheckingResult *codecMatches = | |
47 [regex firstMatchInString:line | |
48 options:0 | |
49 range:NSMakeRange(0, line.length)]; | |
50 if (codecMatches) { | |
51 codecRtpMap = | |
52 [line substringWithRange:[codecMatches rangeAtIndex:1]]; | |
53 continue; | |
54 } | |
55 } | |
56 if (mLineIndex == -1) { | |
57 RTCLog(@"No m=video line, so can't prefer %@", codec); | |
58 return description; | |
59 } | |
60 if (!codecRtpMap) { | |
61 RTCLog(@"No rtpmap for %@", codec); | |
62 return description; | |
63 } | |
64 NSArray *origMLineParts = | |
65 [lines[mLineIndex] componentsSeparatedByString:mLineSeparator]; | |
66 if (origMLineParts.count > 3) { | |
67 NSMutableArray *newMLineParts = | |
68 [NSMutableArray arrayWithCapacity:origMLineParts.count]; | |
69 NSInteger origPartIndex = 0; | |
70 // Format is: m=<media> <port> <proto> <fmt> ... | |
71 [newMLineParts addObject:origMLineParts[origPartIndex++]]; | |
72 [newMLineParts addObject:origMLineParts[origPartIndex++]]; | |
73 [newMLineParts addObject:origMLineParts[origPartIndex++]]; | |
74 [newMLineParts addObject:codecRtpMap]; | |
75 for (; origPartIndex < origMLineParts.count; ++origPartIndex) { | |
76 if (![codecRtpMap isEqualToString:origMLineParts[origPartIndex]]) { | |
77 [newMLineParts addObject:origMLineParts[origPartIndex]]; | |
78 } | |
79 } | |
80 NSString *newMLine = | |
81 [newMLineParts componentsJoinedByString:mLineSeparator]; | |
82 [lines replaceObjectAtIndex:mLineIndex | |
83 withObject:newMLine]; | |
84 } else { | |
85 RTCLogWarning(@"Wrong SDP media description format: %@", lines[mLineIndex]); | |
86 } | |
87 NSString *mangledSdpString = [lines componentsJoinedByString:lineSeparator]; | |
88 return [[RTCSessionDescription alloc] initWithType:description.type | |
89 sdp:mangledSdpString]; | |
90 } | |
91 | |
92 @end | |
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