Error in AVVideoSettingsCompressed

videoSettings = new AVVideoSettingsCompressed
{
    Codec = AVVideoCodec.H264,
    Width = 1078,
    Height = 1645,
};

var assetWriterInput = new AVAssetWriterInput("video", videoSettings);

Error: {ObjCRuntime.ObjCException: Objective-C exception thrown. Name: NSInvalidArgumentException Reason: *** -[AVAssetWriterInput initWithMediaType:outputSettings:sourceFormatHint:] Output settings dictionary is valid
How to solve this problem?

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 42,351 Reputation points Microsoft Vendor

2024-08-21T05:41:33.5766667+00:00

May I know whether your issue has been solved or not? If you're still having problems, please explain in detail what is still going wrong and what you need help with.

Анастасия Зорина 0

Yes, this issue has been resolved, but by changing from "video" to "vide", this part of the code stops working:

NSUrl videoUrl = NSUrl.FromFilename(videoPath); 
AVAsset asset = AVAsset.FromUrl(videoUrl); 
AVAssetImageGenerator imageGenerator = new AVAssetImageGenerator(asset); imageGenerator.AppliesPreferredTrackTransform = true; imageGenerator.MaximumSize = thumbnailSize; 
var Error = new NSError(); 
CMTime test = new CoreMedia.CMTime(0, 1); 
try { 
// null here, the path to the file is 100% correct
CGImage thumbnailImageRef = imageGenerator.CopyCGImageAtTime(test, out _, out Error);
var error = Error.LocalizedDescription; 
// Accordingly, the error crashes here 
UIImage thumbnailImage = UIImage.FromImage(thumbnailImageRef); thumbnailImageRef.Dispose(); return thumbnailImage;

in Xamarin, this part of the code worked well

Michael Taylor 54,311 Reputation points

2024-08-26T13:46:29.2933333+00:00

Please, when you say something isn't working, then you need to provide us the details. What error are you getting? What does the stack trace say? The more you provide the faster things can get resolved.

Just a quick glance at your code tells me you aren't handling errors properly. Error may or may not be set so you cannot just reference it. You should refer to the docs to see how to check for errors. Often you look to see if the return value is successful, or if an error object is returned whether it has a value.

Also, if this is calliing iOS's copyCGImage function then it is deprecated so you'll want to use something else anyway.

Анастасия Зорина 0

Here is the code that records the video, the frameBuffer is updated in another part, but this is the working code, as the videos are created:

// Creating a URL from the file name 
var fileUrl = NSUrl.FromFilename(fileName); 
// Creating an asset writer object 
var error = new NSError(); 
var assetWriter = new AVAssetWriter(fileUrl, "public.mpeg-4", out error); 
// Creating a video writer object 
// Using 'vide' instead of 'video' because it's a joke in iOS... don't use 'video' here, // it breaks 
var assetWriterInput = new AVAssetWriterInput("vide", videoSettings); assetWriterInput.ExpectsMediaDataInRealTime = true; 
// Adding the input object to assetWriter 
assetWriter.AddInput(assetWriterInput); 
// Creating pixel buffer attributes 
var atr = new CVPixelBufferAttributes(CVPixelFormatType.CV32ARGB, (nint)width, (nint)height); 
// Creating a pixel buffer adaptor 
var pixelBufferAdaptor = new AVAssetWriterInputPixelBufferAdaptor(assetWriterInput, atr.Dictionary); 
// Starting the writing process 
assetWriter.StartWriting(); 
// Starting the writing session 
assetWriter.StartSessionAtSourceTime(new CMTime(0, 1000)); 
// Setting the start time 
this.startTime = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(); 
// Recording loop 
while (IsRecording) { 
// Getting the current time 
var currentTime = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(); 
// Creating a timestamp 
int preferredTimescale = 1000; 
// 1000 for milliseconds 
CMTime timestamp = new CMTime(currentTime - startTime, preferredTimescale); 
// Converting the color space 
pixelOutConverted = ConvertRgbaToArgb(frameBuffer, height, width); 
// If ready to write more data 
if (assetWriterInput.ReadyForMoreMediaData) { 
// Adding the pixel buffer with the timestamp 					 pixelBufferAdaptor.AppendPixelBufferWithPresentationTime(CreatePixelBuffer(), timestamp); 					  }		
// Pause between frames 
Thread.Sleep(1000 / fps); 
} 
// Marking the input as finished 
assetWriterInput.MarkAsFinished(); 
// Asynchronously finishing the writing process 
assetWriter.FinishWritingAsync();

The method that makes previews for videos:

private UIImage GenerateVideoThumbnail(string videoPath, CGSize thumbnailSize) { 
// Creating an NSUrl from the video path 
string NSUrl videoUrl = NSUrl.FromFilename(videoPath); 
// Creating an AVAsset from the NSUrl 
AVAsset asset = AVAsset.FromUrl(videoUrl); 
// Creating an AVAssetImageGenerator to generate thumbnails 
AVAssetImageGenerator imageGenerator = new AVAssetImageGenerator(asset); 
// Setting the generation parameters 
imageGenerator.AppliesPreferredTrackTransform = true; 
imageGenerator.MaximumSize = thumbnailSize; 
var Error = new NSError(); 
CMTime test = new CMTime(0, 1); 
// Getting the CGImage thumbnail 
try { 
CMTime actualTime; 
CGImage thumbnailImageRef = imageGenerator.CopyCGImageAtTime(test, out actualTime, out Error); 
// error: Cannot Decode 
var error = Error.LocalizedDescription; 
// Creating a UIImage from the CGImage 
UIImage thumbnailImage = UIImage.FromImage(thumbnailImageRef); 
// Releasing resources 
thumbnailImageRef.Dispose(); 
return thumbnailImage; 
} 
catch (Exception ex) 
{ // Stack trace 
 // " at ObjCRuntime.ThrowHelper.ThrowArgumentNullException(String argumentName) // in /Users/builder/azdo/_work/1/s/xamarin-macios/src/ObjCRuntime/ThrowHelper.cs:line 28\n // at ObjCRuntime.NativeObjectExtensions.GetNonNullHandle(INativeObject self, String argumentName) // in /Users/builder/azdo/_work/1/s/xamarin-macios/src/ObjCRuntime/INativeObject.cs:line 42\n // at UIKit.UIImage.FromImage(CGImage image) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/build/dotnet/ios/generated-sources/UIKit/UIImage.g.cs:line 534\n // at *this method* in *Path*\\MediaService.cs:line 239" 
var stack = ex.StackTrace; } 
return new UIImage(); }

thumbnailImageRef = null
The video starts, it is working, but CopyCGImageAtTime cannot decode

Michael Taylor 54,311 Reputation points

2024-08-26T14:39:19.5866667+00:00

Please identify the error message, stack information, etc that I also asked for.

Also, please use the Add comment button to respond to answers. Creating a new answer each time makes it hard to tell who you're responding to and ultimately will prevent marking the correct answer.

1 answer

Michael Taylor 54,311 Reputation points

2024-08-15T18:30:37.9866667+00:00

You are passing bad data. See here where someone had the exact same problem and was given a solution that seemed to work.
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Error in AVVideoSettingsCompressed

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