問題描述

使用適用于 Windows Phone 的 8.1 MediaCapture 類.

Using the 8.1 MediaCapture classes for Windows Phone.

已聲明音頻"和網(wǎng)絡(luò)攝像頭"的功能，其中 90% 是導(dǎo)致異常的原因.

Have declared the capabilities for "Audio" and "Webcam", which 90% is what would be the cause of the exception.

Kicker 是，它在 WP 模擬器中完美運行，但在實際設(shè)備上中斷.

Kicker is, it works perfectly in the WP emulator, but breaks on an actual device.

確切的例外是這里:

我添加了大量檢查，以確保我們沒有重新初始化已經(jīng)初始化的相機或嘗試在初始化之前讀取..等等(因為我認(rèn)為問題是由以下原因引起的)所以這不太可能就是這樣.

I have added a mountain of checks to make sure we aren't re-initializing the already initialized camera or trying to read before the initializations.. etc (as I assumed the issue was being caused by) So it is very unlikely to be that.

    private async Task InitializeCameraAsync()
    {
        if (_isInitialized)
        {
            Debug.WriteLine("Skipping unnecessary initialization");
            return;
        }

        Debug.WriteLine("Initializing camera media capture...");
        _deviceCapture = new MediaCapture();
        await _deviceCapture.InitializeAsync(new MediaCaptureInitializationSettings
        {
            VideoDeviceId = _cameraInfoCollection[_currentVideoDevice].Id,
            PhotoCaptureSource = PhotoCaptureSource.VideoPreview,
            AudioDeviceId = _microphoneInfoCollection[_currentAudioDevice].Id
            StreamingCaptureMode = StreamingCaptureMode.Video
        });
        Debug.WriteLine("Initialized camera media capture!");

        // For code completion only, unlikely to be relevant

        // Set up low-lag photo capture
        if (IsNotUsingInstantCapture)
        {
            Debug.WriteLine("Preparing low-lag photo capture");
            var imageEncoding = ImageEncodingProperties.CreateJpeg();
            imageEncoding.Width = PhotoCaptureWidth;
            imageEncoding.Height = PhotoCaptureHeight;
            _lowLagPhotoCapture = await _deviceCapture.PrepareLowLagPhotoCaptureAsync(imageEncoding);
        }

        _isInitialized = true;
        Debug.WriteLine("Initialized camera!");
    }

_mediacapture 隨后被綁定到 xaml CaptureElement 的 .source 以顯示預(yù)覽.

_mediacapture is then being bound to the .source of a xaml CaptureElement to show a preview.

推薦答案

這是 Windows api 的臨時錯誤.它已在 2014 年 9 月 24 日發(fā)布的 Windows Phone 8.1 更新中得到修復(fù).

It was a temporary bug with the Windows api. It was fixed with the Windows Phone 8.1 update that was released the 24th of september 2014.

這篇關(guān)于Windows Phone 8.1 相機初始化 - 訪問被拒絕異常的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！