Die Android -Rückfahrkamera zeigt keinen Strom an ⇐ Android

[Anonymous]

Warum kann ich in einem mobilen Gerät den Kameratream sowohl vorne als auch hinten anzeigen, aber in einem anderen nur auf der Vorderseite kann ich nicht. Manchmal kann ich auf einigen anderen Geräten den Vorder- und die Rückfahrkamera -Feed nicht sehen. Ich benutze denselben Browser für alle Geräte. Wenn der Kamera -Stream nicht angezeigt wird, sehe ich nur einen schwarzen Bildschirm. < /P>
Ich weiß, dass meine beiden Kameras funktionieren. Ich bin auf diese Website namens webcAmaTests.com gestoßen. Ich kann tatsächlich meine beiden Kamera -Streams sehen (ein bisschen fantastisch, eigentlich weiß ich nicht, wie sie es gemacht haben). Was ich mit Geräten meine, sind Android -Geräte. Alle von ihnen sind entweder Android 11 oder 13.

Code: Select all

let currentFacingMode = "environment"; // Default to rear camera

function startVideo(src) {
if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
navigator.mediaDevices.getUserMedia(
{
video: {
facingMode: currentFacingMode
}
}).then(function (stream) {
let video = document.getElementById(src);
if ("srcObject" in video) {
video.srcObject = stream;
} else {
video.src = window.URL.createObjectURL(stream);
}
video.onloadedmetadata = function (e) {
video.play();
};
//mirror image
video.style.webkitTransform = "scaleX(-1)";
video.style.transform = "scaleX(-1)";
}).catch(function (error) {
console.error("Error accessing camera: ", error);
alert("Camera not accessible.  Please check permissions and ensure the device supports the requested facing mode.");
});;
}
}

function toggleCamera() {
debugger;
if (currentFacingMode === "user") {
debugger;
currentFacingMode = "environment";
} else {
debugger;
currentFacingMode = "user";
}
stopVideo("videoFeed");
startVideo("videoFeed");
}

function getFrame(src, dest, dotNetHelper) {
let video = document.getElementById(src);
let canvas = document.getElementById(dest);
canvas.getContext('2d').drawImage(video, 0, 0, 320, 240);

let dataUrl = canvas.toDataURL("image/jpeg");
dotNetHelper.invokeMethodAsync('ProcessImage', dataUrl);
}

function stopVideo(src) {
let video = document.getElementById(src);
if (video && "srcObject" in video) {
const stream = video.srcObject;
if (stream) {
const tracks = stream.getTracks();
tracks.forEach(track => {
track.stop();
track.enabled = false;
});
stream.getTracks().forEach(function (track) {
if (track.readyState == 'live' && track.kind === 'video') {
track.stop();
}
});
}
video.srcObject = null;
}
}

< /code>
Dies ist meine Komponente und mein Code hinter Blazor < /p>
@using ITMS_Ver_2.Client.Services
@using ITMS_Ver_2.Shared._Entities
@using SixLabors.Fonts
@using SixLabors.ImageSharp
@using SixLabors.ImageSharp.Drawing
@using SixLabors.ImageSharp.Drawing.Processing
@using SixLabors.ImageSharp.Processing;
@using SixLabors.ImageSharp.Formats.Jpeg
@using SixLabors.Fonts
@using System.Net.Http
@using System.IO



















Take Image

Switch


@if (ImageList != null && ImageList.Any())
{
foreach (var item in ImageList)
{

}
}

@code {

[Inject] private IJSRuntime? JsRuntime { get; set; }
[Inject] private HttpClient? Http { get; set; }
[Inject] private ICommonService? CommonService { get; set; }
[Parameter] public string? IncidentId { get; set; }
[Parameter] public List? ImageList { get; set; }

private string captionText;
private string frameUri;

FontCollection collection = new FontCollection();
FontFamily sansFamily;
Font captionFont;

protected override async Task OnInitializedAsync()
{
await StartCamera();
}

private async Task StartCamera()
{
await JsRuntime!.InvokeVoidAsync("startVideo", "videoFeed");

//Font stored in wwwroot. Fetch it as byte array, and use it
var fontBytes = await Http!.GetByteArrayAsync("OpenSans-Regular.ttf");
collection.Install(new MemoryStream(fontBytes));
collection.TryFind("Open Sans", out sansFamily);
captionFont = sansFamily.CreateFont(16, FontStyle.Regular);
}

private async Task ToggleCamera()
{
await JsRuntime!.InvokeVoidAsync("toggleCamera");
}

private async Task CaptureFrame()
{
await JsRuntime!.InvokeAsync("getFrame", "videoFeed", "currentFrame", DotNetObjectReference.Create(this));
}

[JSInvokable]
public void ProcessImage(string imageString)
{
byte[] imageData = Convert.FromBase64String(imageString.Split(',')[1]);

DrawingOptions alignCenter = new DrawingOptions()
{
TextOptions = new TextOptions()
{
VerticalAlignment = VerticalAlignment.Center,
WrapTextWidth = 304, //Image is 320px wide. This centers with 8px margin on left and right
HorizontalAlignment = SixLabors.Fonts.HorizontalAlignment.Center
}
};

using (var image = SixLabors.ImageSharp.Image.Load(imageData))
{
image.Mutate(x => x
.Flip(FlipMode.Horizontal) //To match mirrored webcam image
.Fill(SixLabors.ImageSharp.Color.ParseHex("0008"), new RectangularPolygon(0, 220, 320, 20)) //Setting footer bar for caption
.DrawText(alignCenter, captionText, captionFont, SixLabors.ImageSharp.Color.White, new PointF(8, 230)) //Centering in footer bar)
);
frameUri = image.ToBase64String(JpegFormat.Instance);
var incidentImage = new IncidentImage
{
IncidentId = IncidentId,
Description = captionText,
ImageString = frameUri,
TimeTaken = DateTime.Now,
FileName = DateTime.Now.ToString("yyyyMMddHHmmss")
};
if (ImageList == null)
{
ImageList = new();
ImageList.Add(incidentImage);
}
else
{
ImageList.Add(incidentImage);
}
captionText = String.Empty;
StartCamera();
}
}
}