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1 /* | 1 /* |
2 * Copyright 2015 The WebRTC Project Authors. All rights reserved. | 2 * Copyright 2015 The WebRTC Project Authors. All rights reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 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 | 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 | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
11 #import "ARDSDPUtils.h" | 11 #import "ARDSDPUtils.h" |
12 | 12 |
13 #import "WebRTC/RTCLogging.h" | 13 #import "WebRTC/RTCLogging.h" |
14 #import "WebRTC/RTCSessionDescription.h" | 14 #import "WebRTC/RTCSessionDescription.h" |
15 | 15 |
16 @implementation ARDSDPUtils | 16 @implementation ARDSDPUtils |
17 | 17 |
18 + (RTCSessionDescription *) | 18 + (RTCSessionDescription *) |
19 descriptionForDescription:(RTCSessionDescription *)description | 19 descriptionForDescription:(RTCSessionDescription *)description |
20 preferredVideoCodec:(NSString *)codec { | 20 preferredVideoCodec:(NSString *)codec { |
21 NSString *sdpString = description.sdp; | 21 NSString *sdpString = description.sdp; |
22 NSString *lineSeparator = @"\n"; | 22 NSString *lineSeparator = @"\n"; |
23 NSString *mLineSeparator = @" "; | 23 NSString *mLineSeparator = @" "; |
24 // Copied from PeerConnectionClient.java. | 24 // Copied from PeerConnectionClient.java. |
25 // TODO(tkchin): Move this to a shared C++ file. | 25 // TODO(tkchin): Move this to a shared C++ file. |
26 NSMutableArray *lines = | 26 NSMutableArray *lines = |
27 [NSMutableArray arrayWithArray: | 27 [NSMutableArray arrayWithArray: |
28 [sdpString componentsSeparatedByString:lineSeparator]]; | 28 [sdpString componentsSeparatedByString:lineSeparator]]; |
| 29 // Find the line starting with "m=video". |
29 NSInteger mLineIndex = -1; | 30 NSInteger mLineIndex = -1; |
30 NSString *codecRtpMap = nil; | 31 for (NSInteger i = 0; i < lines.count; ++i) { |
| 32 if ([lines[i] hasPrefix:@"m=video"]) { |
| 33 mLineIndex = i; |
| 34 break; |
| 35 } |
| 36 } |
| 37 if (mLineIndex == -1) { |
| 38 RTCLog(@"No m=video line, so can't prefer %@", codec); |
| 39 return description; |
| 40 } |
| 41 // An array with all payload types with name |codec|. The payload types are |
| 42 // integers in the range 96-127, but they are stored as strings here. |
| 43 NSMutableArray *codecPayloadTypes = [[NSMutableArray alloc] init]; |
31 // a=rtpmap:<payload type> <encoding name>/<clock rate> | 44 // a=rtpmap:<payload type> <encoding name>/<clock rate> |
32 // [/<encoding parameters>] | 45 // [/<encoding parameters>] |
33 NSString *pattern = | 46 NSString *pattern = |
34 [NSString stringWithFormat:@"^a=rtpmap:(\\d+) %@(/\\d+)+[\r]?$", codec]; | 47 [NSString stringWithFormat:@"^a=rtpmap:(\\d+) %@(/\\d+)+[\r]?$", codec]; |
35 NSRegularExpression *regex = | 48 NSRegularExpression *regex = |
36 [NSRegularExpression regularExpressionWithPattern:pattern | 49 [NSRegularExpression regularExpressionWithPattern:pattern |
37 options:0 | 50 options:0 |
38 error:nil]; | 51 error:nil]; |
39 for (NSInteger i = 0; (i < lines.count) && (mLineIndex == -1 || !codecRtpMap); | 52 for (NSString *line in lines) { |
40 ++i) { | |
41 NSString *line = lines[i]; | |
42 if ([line hasPrefix:@"m=video"]) { | |
43 mLineIndex = i; | |
44 continue; | |
45 } | |
46 NSTextCheckingResult *codecMatches = | 53 NSTextCheckingResult *codecMatches = |
47 [regex firstMatchInString:line | 54 [regex firstMatchInString:line |
48 options:0 | 55 options:0 |
49 range:NSMakeRange(0, line.length)]; | 56 range:NSMakeRange(0, line.length)]; |
50 if (codecMatches) { | 57 if (codecMatches) { |
51 codecRtpMap = | 58 [codecPayloadTypes |
52 [line substringWithRange:[codecMatches rangeAtIndex:1]]; | 59 addObject:[line substringWithRange:[codecMatches rangeAtIndex:1]]]; |
53 continue; | |
54 } | 60 } |
55 } | 61 } |
56 if (mLineIndex == -1) { | 62 if ([codecPayloadTypes count] == 0) { |
57 RTCLog(@"No m=video line, so can't prefer %@", codec); | 63 RTCLog(@"No payload types with name %@", codec); |
58 return description; | |
59 } | |
60 if (!codecRtpMap) { | |
61 RTCLog(@"No rtpmap for %@", codec); | |
62 return description; | 64 return description; |
63 } | 65 } |
64 NSArray *origMLineParts = | 66 NSArray *origMLineParts = |
65 [lines[mLineIndex] componentsSeparatedByString:mLineSeparator]; | 67 [lines[mLineIndex] componentsSeparatedByString:mLineSeparator]; |
66 if (origMLineParts.count > 3) { | 68 // The format of ML should be: m=<media> <port> <proto> <fmt> ... |
67 NSMutableArray *newMLineParts = | 69 const int kHeaderLength = 3; |
68 [NSMutableArray arrayWithCapacity:origMLineParts.count]; | 70 if (origMLineParts.count <= kHeaderLength) { |
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]); | 71 RTCLogWarning(@"Wrong SDP media description format: %@", lines[mLineIndex]); |
| 72 return description; |
86 } | 73 } |
| 74 // Split the line into header and payloadTypes. |
| 75 NSRange headerRange = NSMakeRange(0, kHeaderLength); |
| 76 NSRange payloadRange = |
| 77 NSMakeRange(kHeaderLength, origMLineParts.count - kHeaderLength); |
| 78 NSArray *header = [origMLineParts subarrayWithRange:headerRange]; |
| 79 NSMutableArray *payloadTypes = [NSMutableArray |
| 80 arrayWithArray:[origMLineParts subarrayWithRange:payloadRange]]; |
| 81 // Reconstruct the line with |codecPayloadTypes| moved to the beginning of the |
| 82 // payload types. |
| 83 NSMutableArray *newMLineParts = [NSMutableArray arrayWithCapacity:origMLinePar
ts.count]; |
| 84 [newMLineParts addObjectsFromArray:header]; |
| 85 [newMLineParts addObjectsFromArray:codecPayloadTypes]; |
| 86 [payloadTypes removeObjectsInArray:codecPayloadTypes]; |
| 87 [newMLineParts addObjectsFromArray:payloadTypes]; |
| 88 |
| 89 NSString *newMLine = [newMLineParts componentsJoinedByString:mLineSeparator]; |
| 90 [lines replaceObjectAtIndex:mLineIndex |
| 91 withObject:newMLine]; |
| 92 |
87 NSString *mangledSdpString = [lines componentsJoinedByString:lineSeparator]; | 93 NSString *mangledSdpString = [lines componentsJoinedByString:lineSeparator]; |
88 return [[RTCSessionDescription alloc] initWithType:description.type | 94 return [[RTCSessionDescription alloc] initWithType:description.type |
89 sdp:mangledSdpString]; | 95 sdp:mangledSdpString]; |
90 } | 96 } |
91 | 97 |
92 @end | 98 @end |
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