libjingle iOS: 不要请求麦克风许可

Question

我正在开发 WebRTC iOS 应用程序以从网络摄像头接收 video/audio。只有网络摄像头发送视频和音频，移动设备不发送任何内容。

我正在使用来自 CocoaPods (v11177.2.0) 的 libjingle_peerconnection 库。

一切正常，我可以正常接收视频和音频，但设备权限有问题。我第一次使用该应用程序时，当我想从网络摄像头接收视频时，iOS 应用程序要求获得麦克风许可。这很重要，因为设备不发送音频，而我的客户说 "Why the app is asking for the microphone??"

这很奇怪，因为对于相机，应用程序不需要任何权限。

我已经检查了 SDP，似乎都可以（提供和回答）。

这是我创建对等连接对象的方式没有附加流:

RTCICEServer *stunServer = [[RTCICEServer alloc]initWithURI:[NSURL URLWithString:@"stun:stun.l.google.com:19302"] username:@"" password:@""];
    NSMutableArray *iceServers = [NSMutableArray arrayWithObject:stunServer];

RTCPeerConnectionFactory *factory = [[RTCPeerConnectionFactory alloc]init];

NSArray *peerConnectionConstraints = @[[[RTCPair alloc] initWithKey:@"DtlsSrtpKeyAgreement" value:@"true"]];
RTCMediaConstraints *peerConnectionConstraints = [[RTCMediaConstraints alloc]initWithMandatoryConstraints:peerConnectionConstraints optionalConstraints:nil];

RTCPeerConnection *pConnection = [factory peerConnectionWithICEServers:iceServers constraints:peerConnectionConstraints delegate:self];

NSArray *sdpConstraints = @[[[RTCPair alloc] initWithKey:@"OfferToReceiveAudio" value:@"true"],
                            [[RTCPair alloc] initWithKey:@"OfferToReceiveVideo" value:@"true"]];

RTCMediaConstraints* sdpConstraints = [[RTCMediaConstraints alloc] initWithMandatoryConstraints:sdpConstraints optionalConstraints:nil];
[pConnection createOfferWithDelegate:self constraints:sdpConstraints];

这是生成的 SDP 报价：

v=0
o=- 6528383367639880158 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE audio video
a=msid-semantic: WMS
m=audio 9 RTP/SAVPF 111 103 104 9 102 0 8 127 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:0QOsaBCKhCBBcHz5
a=ice-pwd:/y5snrrO3Qmq37m2aejRbK1E
a=mid:audio
a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
a=extmap:3 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=recvonly
a=rtcp-mux
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:x1lfnVdo9lCRa9ykH6759WhY1SnI+dbLjKNbkTl+
a=rtpmap:111 opus/48000/2
a=fmtp:111 minptime=10; useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:127 red/8000
a=rtpmap:126 telephone-event/8000
a=maxptime:60
m=video 9 RTP/SAVPF 100 101 116 117 96
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:0QOsaBCKhCBBcHz5
a=ice-pwd:/y5snrrO3Qmq37m2aejRbK1E
a=mid:video
a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
a=extmap:3 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=extmap:4 urn:3gpp:video-orientation
a=recvonly
a=rtcp-mux
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:x1lfnVdo9lCRa9ykH6759WhY1SnI+dbLjKNbkTl+
a=rtpmap:100 VP8/90000
a=rtcp-fb:100 ccm fir
a=rtcp-fb:100 nack
a=rtcp-fb:100 nack pli
a=rtcp-fb:100 goog-remb
a=rtcp-fb:100 transport-cc
a=rtpmap:101 VP9/90000
a=rtcp-fb:101 ccm fir
a=rtcp-fb:101 nack
a=rtcp-fb:101 nack pli
a=rtcp-fb:101 goog-remb
a=rtcp-fb:101 transport-cc
a=rtpmap:116 red/90000
a=rtpmap:117 ulpfec/90000
a=rtpmap:96 rtx/90000
a=fmtp:96 apt=100

这是来自网络摄像头的 SDP 回答：

v=0
o=- 3699612909 3699612909 IN IP4 0.0.0.0
s=-
c=IN IP4 0.0.0.0
t=0 0
a=msid-semantic: WMS
a=group:BUNDLE audio video
m=audio 1 RTP/SAVPF 111 0
a=extmap:3 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=mid:audio
a=rtcp:9 IN IP4 0.0.0.0
a=rtpmap:111 opus/48000/2
a=rtpmap:0 PCMU/8000
a=sendonly
a=rtcp-mux
a=fmtp:111 minptime=10; useinbandfec=1
a=maxptime:60
a=ssrc:3192391506 cname:user604422501@host-6a96398f
a=ice-ufrag:r2kq
a=ice-pwd:6VJu/y0Kbc4iUDQB/1ZrnE
a=fingerprint:sha-256 57:26:29:A5:DD:CD:42:74:C9:A3:BB:C4:67:D1:1C:24:E9:4B:4C:86:6F:93:32:03:52:6B:2B:77:B3:C4:E8:88
m=video 1 RTP/SAVPF 100
a=extmap:3 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=mid:video
a=rtcp:9 IN IP4 0.0.0.0
a=rtpmap:100 VP8/90000
a=rtcp-fb:100 ccm fir
a=rtcp-fb:100 nack
a=rtcp-fb:100 nack pli
a=rtcp-fb:100 goog-remb
a=sendonly
a=rtcp-mux
a=ssrc:455461391 cname:user604422501@host-6a96398f
a=ice-ufrag:r2kq
a=ice-pwd:6VJu/y0Kbc4iUDQB/1ZrnE
a=fingerprint:sha-256 57:26:29:A5:DD:CD:42:74:C9:A3:BB:C4:67:D1:1C:24:E9:4B:4C:86:6F:93:32:03:52:6B:2B:77:B3:C4:E8:88

如您所见，在 SDP 报价中，两种媒体（音频和视频）都是 "receiveOnly" 并且在 SDP 答案中 "sendOnly"，所以我认为没有与SDP.

有人知道为什么要请求麦克风许可吗？如果您需要更多信息，请告诉我。

谢谢！

Answer 1

我没有和你的 code/libraries 合作过，对于那部分我无能为力，但是从 Apple documentation 我们可以读到：

The first time your app’s audio session attempts to use an audio input route while using a category that enables recording, the system automatically prompts the user for permission. You can explicitly ask earlier by calling the requestRecordPermission(_:) method. Until the user grants your app permission to record, your app can record only silence.

这可能会给你一些线索，某处（可能在 libjingle 中）正在访问 iOS Audio Session 并且可能是什么触发了麦克风权限。

Answer 2

给你。您需要像

这样创建本地流

 -(RTCMediaStream*)createLocalMediaStream
{
RTCMediaStream* localStream = [_factory mediaStreamWithLabel:@"ARDAMS"];

if(![[ReveSingleton sharedManager].localCallControl isEqualToNumber:@251])
{
    RTCVideoTrack* localVideoTrack;
    localVideoTrack = [self createLocalVideoTrack];

    if (localVideoTrack) {
        [localStream addVideoTrack:localVideoTrack];
        [_delegate appClient:self didReceiveLocalVideoTrack:localVideoTrack];
    }
}

[localStream addAudioTrack:[_factory audioTrackWithID:@"ARDAMSa0"]];
if (_isSpeakerEnabled)
    [self enableSpeaker];
return localStream;
}

createLocalVideoTrack 方法会像

- (RTCVideoTrack*)createLocalVideoTrack
{

RTCVideoTrack* localVideoTrack = nil;
#if !TARGET_IPHONE_SIMULATOR && TARGET_OS_IPHONE

NSString* cameraID = nil;
for (AVCaptureDevice* captureDevice in
    [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]) {
    if (captureDevice.position == AVCaptureDevicePositionFront) {
        cameraID = [captureDevice localizedName];
        [captureDevice lockForConfiguration:nil];
        //configure frame rate

        [captureDevice unlockForConfiguration];
       // [AVCaptureDevice release];
        break;
    }
}
NSAssert(cameraID, @"Unable to get the front camera id");

RTCVideoCapturer* capturer = [RTCVideoCapturer capturerWithDeviceName:cameraID];
RTCMediaConstraints* mediaConstraints = [self defaultMediaStreamConstraints];
RTCVideoSource* videoSource = [_factory videoSourceWithCapturer:capturer constraints:mediaConstraints];
localVideoTrack = [_factory videoTrackWithID:@"ARDAMSv0" source:videoSource];
#endif
return localVideoTrack;


}

处理代码时，将在屏幕上询问相机和麦克风权限。

libjingle iOS: 不要请求麦克风许可

libjingle iOS: Don't ask for mic permission

libjingle

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webrtc