How to generate thumbnail without stream?

Knowledge
1

We need to get a thumbnail in 1-2 seconds from MP4, but the default encoding mechanism needs to create steam and muxing.
How we can do it? We can’t “Encodings.Thumbnails”


   var thumbnail = new Thumbnail
        {
            Height = 72,
            Width = 128,
            Positions = new List<double?> { 1 },
            Unit = ThumbnailUnit.SECONDS,
            Pattern = "thumbnail-%number%.jpg",
            Outputs = new List<EncodingOutput> { BuildEncodingOutput(output, "/thumbnails") }
        };

        await _bitmovinApi.Encoding.Encodings.Thumbnails.CreateAsync(encoding.Id, thumbnail);