c# – IOS客户端流媒体视频问题(在ASP.NET WEB API 2上开发的服务器)

流媒体视频有问题.我在ASP.NET Web API 2上开发了服务器并实现了两种方法：

第一种方法：

if (Request.Headers.Range != null)
    {
        try
        {
            var httpResponce = Request.CreateResponse();
            httpResponce.Content =
                new PushStreamContent((Action<Stream, HttpContent, TransportContext>) WriteContentToStream);

            return httpResponce;
        }
        catch (Exception ex)
        {
            return new HttpResponseMessage(HttpStatusCode.InternalServerError);
        }
    }
    else
    {
        return new HttpResponseMessage(HttpStatusCode.RequestedRangeNotSatisfiable);
    }

/*method for streaming*/

private async void WriteContentToStream(Stream outputStream, HttpContent content, TransportContext transportContext)
{
    string relativeFilePath = "~/App_Data/Videos/4.mp4";
    try
    {
        var filePath = System.Web.Hosting.HostingEnvironment.MapPath(relativeFilePath);

        int bufferSize = 1000;
        byte[] buffer = new byte[bufferSize];
        using (var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read))
        {
            int totalSize = (int)fileStream.Length;
            while (totalSize > 0)
            {
                int count = totalSize > bufferSize ? bufferSize : totalSize;
                int sizeOfReadedBuffer = fileStream.Read(buffer, 0, count);
                await outputStream.WriteAsync(buffer, 0, sizeOfReadedBuffer);
                totalSize -= sizeOfReadedBuffer;
            }
        }
    }
    catch (HttpException ex)
    {
        if (ex.ErrorCode == -2147023667)  
        {
            return;
        }
    }
    finally
    {
        outputStream.Close();
    }
}

2)第二种方法：

public HttpResponseMessage Test()
{
    if (Request.Headers.Range != null)
    {
        try 
        {
            string relativeFilePath = "~/App_Data/Videos/4.mp4";
            var filePath = System.Web.Hosting.HostingEnvironment.MapPath(relativeFilePath);
            HttpResponseMessage partialResponse = Request.CreateResponse(HttpStatusCode.PartialContent);
            partialResponse.Headers.AcceptRanges.Add("bytes");
            var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
            partialResponse.Content = new ByteRangeStreamContent(stream, Request.Headers.Range, new MediaTypeHeaderValue("video/mp4")); 
            return partialResponse;
        }
        catch (Exception)
        {
            return new HttpResponseMessage(HttpStatusCode.InternalServerError);
        }
    }   
    else
    {
        return new HttpResponseMessage(HttpStatusCode.RequestedRangeNotSatisfiable);    
    }
}

这两种方法都适用于Web客户端和Android客户端,但iOS客户端不显示视频.

我认为,问题可能出在视频编解码器上(但我使用的是编解码器,推荐使用Apple)或http-headers.

解决方法:

我刚刚解决了这个,这是因为Content-Length标头(iOS认为是)无效值.

我的解决方案基于上面的方法#2 …
这是我的代码中实际工作的重要部分.

if (!file.Exists) {
    response.StatusCode = HttpStatusCode.NotFound;
    response.ReasonPhrase = "Deleted";
} else {
    var range = Request.Headers.Range?.Ranges?.FirstOrDefault();
    if (range == null) {
        using (var stream = new MemoryStream()) {
            using (var video = file.OpenRead()) await video.CopyToAsync(stream);
            response.Content = new ByteArrayContent(stream.ToArray());
        }
        response.Content.Headers.ContentType = new MediaTypeHeaderValue("video/mp4");
        response.Content.Headers.ContentLength = file.Length;
    } else {
        var stream = new MemoryStream();
        using (var video = file.OpenRead()) await video.CopyToAsync(stream);
        response.Content = new ByteRangeStreamContent(
            stream,
            new RangeHeaderValue(range.From, range.To),
            new MediaTypeHeaderValue("video/mp4")
        );
        //  response.Content.Headers.ContentLength = file.Length;
        // this is what makes iOS work
        response.Content.Headers.ContentLength = (range.To.HasValue ? range.To.Value + 1 : file.Length) - (range.From ?? 0);
    }
    response.StatusCode = HttpStatusCode.OK;
}

在处理范围时,我应该放入HTTP 206(部分内容)状态,但在提出解决方案之前,我正在研究这个状态将近两天.

我还没有完全追踪的唯一问题是,有时候,Application_EndRequest不会触发其中的一些.我能够记录端点发送的响应,但就像iOS在某处断开连接并且请求挂起,直到它在内部超时.