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c# - 在 UWP 中渲染视频时出现异常

问题描述

我正在用 C# 创建一个 UWP 应用程序，它下载视频并允许用户修剪视频持续时间并以三种不同的模式保存电影：视频和音频 (.mp4)、仅视频 (.mp4) 和仅音频 ( .mp3)。目前它只支持 Twitch VOD，所以输入视频是 .ts 文件。

下载工作正常，但渲染有问题。我正在使用 Windows.Media.Editing 命名空间来编辑视频。我可以创建合成、创建媒体剪辑、设置修剪时间和音量、将剪辑添加到合成并开始渲染。

一些视频在处理过程中抛出错误：

System.Exception
  HResult=0xC00DA7FC
  Message=Stream is not in a state to handle the request.
Stream is not in a state to handle the request.
  Source=System.Private.CoreLib
  StackTrace:
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at ProgramName.Core.Sources.Video.<DownloadTaskAsync>d__96.MoveNext() in D:\Project\Core\Sources\Video.cs:line 645
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at ProgramName.Core.Sources.Video.<Download>d__92.MoveNext() in D:\Project\Core\Sources\Video.cs:line 509
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at ProgramName.Core.Sources.Video.<DownloadOrCancelButtonClicked>d__95.MoveNext() in D:\Project\Core\Sources\Video.cs:line 563

其他在开始时抛出错误（0％）：

System.Exception
  HResult=0xC00D6D60
  Message=A valid type has not been set for this stream or a stream that it depends on. (Exception from HRESULT: 0xC00D6D60)
  Source=System.Private.CoreLib
  StackTrace:
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at ProgramName.Core.Sources.Video.<DownloadTaskAsync>d__96.MoveNext() in D:\Project\Core\Sources\Video.cs:line 645
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at ProgramName.Core.Sources.Video.<Download>d__92.MoveNext() in D:\Project\Core\Sources\Video.cs:line 509
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at ProgramName.Core.Sources.Video.<DownloadStopButtonClicked>d__95.MoveNext() in D:\Project\Core\Sources\Video.cs:line 563

只有一小部分视频完全呈现。

下面是一段负责视频处理的代码：

// Init media composition and add clip
MediaComposition composition = new MediaComposition();
StorageFile inputVideoFile = await TempDownloadFolder.GetFileAsync(downloadTempFilename);
MediaClip video = await MediaClip.CreateFromFileAsync(inputVideoFile);

// TrimStart and TrimEnd are TimeSpan variables
// Trim at start
if (0 < TrimStart.TotalMilliseconds && TrimStart.TotalMilliseconds < Duration.TotalMilliseconds)
{
    video.TrimTimeFromStart = TrimStart;
}

// Trim at end
if (0 < TrimEnd.TotalMilliseconds && TrimEnd.TotalMilliseconds < Duration.TotalMilliseconds)
{
    video.TrimTimeFromEnd = TrimEnd;
}

// MediaType is string variable. V - Only video mode, A - Only audio mode, AV - Audio & Video mode
// Only video mode
if (MediaType == "V")
{
    video.Volume = 0;
}

// Add video to composition
composition.Clips.Add(video);

// Render
IAsyncOperationWithProgress<TranscodeFailureReason, double> saveOperation;
if (MediaType == "A") // Only audio mode
{
    saveOperation = composition.RenderToFileAsync(outputVideoFile, MediaTrimmingPreference.Precise, MediaEncodingProfile.CreateMp3(AudioEncodingQuality.Medium));
}
else // Only video and Audio & Video mode
{
    saveOperation = composition.RenderToFileAsync(outputVideoFile, MediaTrimmingPreference.Precise);
}
saveOperation.Progress = new AsyncOperationProgressHandler<TranscodeFailureReason, double>(RenderVideoProgressEvent);
try
{
    await saveOperation.AsTask(token); // This line throws an exceptions
}
catch (TaskCanceledException) { }

我不知道问题出在哪里。

标签： c#.net-corevideouwp

解决方案

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