ios - 在 webRTC iOS 中设置视频大小

Question

我正在使用 RTCMediaConstraints 来创建 RTCPeerConnection 和发送 SDP，但我觉得与视频最大宽度/高度相关的可选约束没有得到遵守。

- (RTCMediaConstraints *)mediaConstraints {

    RTCPair *audioConstraint = [[RTCPair alloc] initWithKey:kKeyOfferToReceiveAudio value:kKeyTrue];
    RTCPair *videoConstraint = [[RTCPair alloc] initWithKey:kKeyOfferToReceiveVideo value:kKeyTrue];

    RTCPair *sctpConstraint = [[RTCPair alloc] initWithKey:kKeyInternalSctpDataChannels value:kKeyTrue];
    RTCPair *dtlsConstraint = [[RTCPair alloc] initWithKey:kKeyDtlsSrtpKeyAgreement value:kKeyTrue];

    RTCPair *maxWidth = [[RTCPair alloc] initWithKey:kKeyMaxWidth value:@"640"];
    RTCPair *minWidth = [[RTCPair alloc] initWithKey:kKeyMinWidth value:@"320"];

    RTCPair *maxHeight = [[RTCPair alloc] initWithKey:kKeyMaxHeight value:@"480"];
    RTCPair *minHeight = [[RTCPair alloc] initWithKey:kKeyMinHeight value:@"240"];

    RTCPair *maxFrameRate = [[RTCPair alloc] initWithKey:kKeyMaxFrameRate value:@"30"];
    RTCPair *minFrameRate = [[RTCPair alloc] initWithKey:kKeyMinFrameRate value:@"24"];

    RTCPair *minAspectRatio = [[RTCPair alloc] initWithKey:@"minAspectRatio" value:@"4:3"];
    RTCPair *maxAspectRatio = [[RTCPair alloc] initWithKey:kKeyMaxAspectRatio value:@"4:3"];

    return [[RTCMediaConstraints alloc] initWithMandatoryConstraints:@[audioConstraint, videoConstraint]
                                                 optionalConstraints:@[sctpConstraint, dtlsConstraint, maxAspectRatio, minAspectRatio, minFrameRate, maxFrameRate, maxWidth, minWidth, maxHeight, minHeight]];
}

当我为 RTCVideoSource 添加约束时，我只看到没有视频的黑屏。

RTCVideoCapturer *capturer = [RTCVideoCapturer capturerWithDeviceName:[device localizedName]];
RTCVideoSource *videoSource = [_peerFactory videoSourceWithCapturer:capturer constraints:[self mediaConstraints]];
RTCVideoTrack *videoTrack = [_peerFactory videoTrackWithID:[[NSUUID UUID] UUIDString] source:videoSource];

[_localMediaStream addVideoTrack:videoTrack];

有人对此有什么建议吗？

Answer 1

查看WebRTC的RTCMediaConstraints.h文件，没有kKeyOfferToReceiveAudio和kKeyOfferToReceiveVideo的 key 。 RTCMediaConstraints 不支持这些语句，这可能是一个问题。