Azure mediaserver video encoding / thumbnail task failure

Question

We use azure media server for encoding and generating thumbnail. We have the following code for a combined task for encoding and generating thumbnail

IJob job = _context.Jobs.Create(filename + " - Media Encoder Standard");

        IMediaProcessor processor = GetLatestMediaProcessorByName("Media Encoder Standard");

        ITask task = job.Tasks.AddNew("Media Encoder Standard", processor, "H264 Single Bitrate 720p for Android", options);

        // Specify the input asset to be encoded.
        task.InputAssets.Add(asset);

        task.OutputAssets.AddNew("Output asset",
        AssetCreationOptions.None);

        task = job.Tasks.AddNew("Media Encoder Standard", processor, configuration, options);

        // Specify the input asset to be encoded.
        task.InputAssets.Add(asset);

        task.OutputAssets.AddNew("Output asset",
        AssetCreationOptions.None);

        // Submit the job and wait until it is completed.
        job.Submit();

        job = job.StartExecutionProgressTask(
            j =>
            {
            },
            CancellationToken.None).Result;

        Console.WriteLine("Transcoding job finished.");

        var outputAssets = job.OutputMediaAssets.ToList();

        return outputAssets;

However if the thumbnail task fails and the video encoding goes through. We still generate a url for the video.

we use the following code for generating the url

 public string PublishAssetGetURLs(IAsset asset, string fileExt = "")
    {
        // Publish the output asset by creating an Origin locator for adaptive streaming,
        // and a SAS locator for progressive download.

        _context.Locators.Create(
            LocatorType.Sas,
            asset,
            AccessPermissions.Read,
            TimeSpan.FromDays(365));

        IEnumerable<IAssetFile> assetFiles = asset
            .AssetFiles
            .ToList()
            .Where(af => af.Name.EndsWith(fileExt, StringComparison.OrdinalIgnoreCase));

        // Get the URls for progressive download for each specified file that was generated as a result
        // of encoding.

        List<Uri> sasUris = assetFiles.Select(af => af.GetSasUri()).ToList();

        var url = sasUris.FirstOrDefault();

        if (url != null)
        {
            return url.ToString();
        }

        return string.Empty;
    }

However when the url is used we get the following xml

    <Error><Code>AuthenticationFailed</Code><Message>Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
RequestId:a6d14469-0001-0008-7bdb-1f3b8a000000
Time:2017-08-28T08:58:17.0773123Z</Message><AuthenticationErrorDetail>Signature fields not well formed.</AuthenticationErrorDetail></Error>

It works fine if both tasks are success. Do I need to set something on the asset or something?

Answer 1

Apparantly I was wrong about my assumption. It was only sometimes i would break. It was caused by the url created by the sas locator. Sometimes it would have a + char and that would lead to the error. However if it was encoded it worked like a charm. I need more coffee

Answer 2

Glad that you seem to have fixed the locator creation error yourself. However, you also mention that sometimes the encode Task succeeds while the Thumbnail Task errors out. Are you trying to generate a thumbnail at a specific timestamp/timecode in the input video? That is usually the only case I've come across where encode succeeds and thumbnail fails. If you can share the thumbnail preset you are using, we can take a further look.

Lastly, in https://learn.microsoft.com/en-us/azure/media-services/media-services-dotnet-generate-thumbnail-with-mes, there is an example showing you can combine the encoding and thumbnail generation into one Task.