AdaptationSet has the wrong mimetype for my text track. Is this a bug with azure media services?

Jason Wisener 26

We have encoded a video assest (using DRM, playread and widevine), the video and audio work fine, but the azure media player (amp) is throwing console errors when it comes to the captions/subtitles:

azuremediaplayer.min.js:13 [14:44:34.651] error: azureHtml5JS: manifestParser: Stream type not supported: text

The following: AdaptationSet

The contentType looks correct, however; the mimeType appears to be wrong.

Is this a bug with azure media services?

1 answer

brtrach-MSFT 15,251 Reputation points Microsoft Employee

2023-06-02T02:31:52.54+00:00

It seems that the mimeType specified in the AdaptationSet is incorrect. The mimeType should be set to "application/ttml+xml" for text tracks. You can try changing the mimeType to "application/ttml+xml" and see if that resolves the issue.

If that does not resolve this issue, please reply to this message so we can put you in touch with support to see if there is a platform issue.

We look forward to your reply.
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brtrach-MSFT 15,251 Reputation points Microsoft Employee

2023-06-02T13:00:29.1266667+00:00

@Jason Wisener My apologies for not being clearer in my initial reply. You are correct that the manifest is generated by Azure Media Services and cannot be modified directly.

However, when you create a new asset and re-encode the video with the correct mimeType for the text track, the new manifest that is generated by Azure Media Services will include the correct mimeType for the text track.

In other words, by creating a new asset and re-encoding the video, you are creating a new manifest that includes the correct mimeType for the text track.

Here are the high-level steps to create a new asset and re-encode the video with the correct mimeType for the text track using the Azure Media Services SDK for .NET:

Install the Azure Media Services SDK for .NET using NuGet.

Create a new instance of the CloudMediaContext class using your Azure Media Services account credentials.

Create a new Asset object using the Create method of the Asset class.

Upload the video files for the asset using the AssetFile class and the UploadAsync method.

Create a new Job object using the Create method of the Job class.

Add a new Task to the job using the AddNewTask method of the Job class.

Configure the encoding settings for the task, including the correct mimeType for the text track.

Submit the job using the Submit method of the Job class.

Wait for the job to complete using the GetExecutionProgressTask method of the Job class.

Retrieve the streaming URL for the new asset using the GetStreamingUrl method of the Asset class.

Here is some sample code that demonstrates these steps:

// Create a new instance of the CloudMediaContext class CloudMediaContext context = new CloudMediaContext(accountName, accountKey); // Create a new Asset object Asset asset = context.Assets.Create("NewAsset", AssetCreationOptions.None); // Upload the video files for the asset AssetFile videoFile = asset.AssetFiles.Create("video.mp4"); videoFile.UploadAsync(videoFilePath).Wait(); AssetFile subtitleFile = asset.AssetFiles.Create("subtitles.ttml"); subtitleFile.UploadAsync(subtitleFilePath).Wait(); // Create a new Job object Job job = context.Jobs.Create("NewJob"); // Add a new Task to the job IMediaProcessor processor = context.MediaProcessors.GetLatestMediaProcessorByName("Azure Media Encoder"); ITask task = job.Tasks.AddNew("NewTask", processor, "H264 Adaptive Bitrate MP4 Set 720p", TaskOptions.None); // Configure the encoding settings for the task task.InputAssets.Add(asset); task.OutputAssets.AddNew("NewAsset", AssetCreationOptions.None); //Set the mimeType for the next track task.OutputAssests[0].AssetFiles[1].MimeType = "application/ttml+xml";

In this example, the mimeType for the text track is set to "application/ttml+xml". You can replace this value with the correct mimeType for your text track.

If this helps to resolve the previous survey feedback, I kindly ask that you fill out a new survey as this will help me and assist our leadership in understanding this issue has been resolved.

If you still need assistance or the above steps do not resolve your issue, please reply to this message and we will see how to address any further concerns or issues that might arise.

Jason Wisener 26 Reputation points

2023-06-02T13:37:17.7033333+00:00

Is that code using the lastest SDK?

Jason Wisener 26 Reputation points

2023-06-02T14:38:13.7+00:00

The vtt file that has been added, is added correctly. when I look at the blob storage file (that is the associated with the track) in azure media services the content type is set correctly:

The error is the azure media services is not setting it correctly in the manifest file that gets generated.

brtrach-MSFT 15,251 Reputation points Microsoft Employee

2023-06-05T15:47:48.6333333+00:00

@Jason Wisener Thank you for the confirmation that the settings are correct. At this point, there is a chance this is a product issue. Let's get you a support ticket so you can work one on one with a support engineer. Can you please email me at azcommunity@microsoft.com with the subject as ATTN: Bryan and in the body of the email include your Azure subscription ID. We look forward to your reply.

Anonymous

2023-06-06T23:15:50.06+00:00

I had a similar error when using VideoJS player - my fix was to remove the .cmft file (in the Tracks list set PlayerVisibility to 'hidden'). This results in only the transcript.vtt remaining in the blob container, and then load it programatically via javascript.

e.g.

player.addRemoteTextTrack( { kind: "subtitles", src: subtitlesUrl, label: "English", language: "en", srcLang: "en", default: false, }, false );
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