AudioDecoder.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using Waher.Runtime.Inventory;
 
namespace Waher.Content.Audio
{
    public class AudioDecoder : IContentDecoder
    {
        public AudioDecoder()
        {
        }
 
        public static readonly string[] AudioContentTypes = new string[] 
        {
            "audio/basic", 
            "audio/mid", 
            "audio/mpeg", 
            "audio/ogg", 
            "audio/x-aiff", 
            "audio/x-mpegurl", 
            "audio/x-pn-realaudio", 
            "audio/x-pn-realaudio", 
            "audio/x-wav"
        };
 
        public static readonly string[] AudioFileExtensions = new string[] 
        {
            "au", 
            "snd", 
            "mid", 
            "rmi", 
            "mp3", 
            "ogg", 
            "oga", 
            "aif", 
            "aifc", 
            "aiff", 
            "m3u", 
            "ra", 
            "ram",
            "wav"
        };
 
        public string[] ContentTypes => AudioContentTypes;
 
        public string[] FileExtensions => AudioFileExtensions;
 
        public bool Decodes(string ContentType, out Grade Grade)
        {
            if (ContentType.StartsWith("audio/"))
            {
                Grade = Grade.Barely;
                return true;
            }
            else
            {
                Grade = Grade.NotAtAll;
                return false;
            }
        }
 
        public Task<object> DecodeAsync(string ContentType, byte[] Data, Encoding Encoding, KeyValuePair<string, string>[] Fields, Uri BaseUri)
        {
            return Task.FromResult<object>(Data);
        }
 
        public bool TryGetContentType(string FileExtension, out string ContentType)
        {
            switch (FileExtension.ToLower())
            {
                case "au":
                case "snd":
                    ContentType = "audio/basic";
                    return true;
 
                case "mid":
                case "rmi":
                    ContentType = "audio/mid";
                    return true;
 
                case "mp3":
                    ContentType = "audio/mpeg";
                    return true;
 
                case "ogg":
                case "oga":
                    ContentType = "audio/ogg";
                    return true;
 
                case "aif":
                case "aifc":
                case "aiff":
                    ContentType = "audio/x-aiff";
                    return true;
 
                case "m3u":
                    ContentType = "audio/x-mpegurl";
                    return true;
 
                case "ra":
                case "ram":
                    ContentType = "audio/x-pn-realaudio";
                    return true;
 
                case "wav":
                    ContentType = "audio/x-wav";
                    return true;
 
                default:
                    ContentType = string.Empty;
                    return false;
            }
        }
 
        public bool TryGetFileExtension(string ContentType, out string FileExtension)
        {
            switch (ContentType.ToLower())
            {
                case "audio/basic":
                    FileExtension = "snd";
                    return true;
 
                case "audio/mid":
                    FileExtension = "mid";
                    return true;
 
                case "audio/mpeg":
                    FileExtension = "mp3";
                    return true;
 
                case "audio/ogg":
                    FileExtension = "oga";
                    return true;
 
                case "audio/x-aiff":
                    FileExtension = "aiff";
                    return true;
 
                case "audio/x-mpegurl":
                    FileExtension = "m3u";
                    return true;
 
                case "audio/x-pn-realaudio":
                    FileExtension = "ra";
                    return true;
 
                case "audio/x-wav":
                    FileExtension = "wav";
                    return true;
 
                default:
                    FileExtension = string.Empty;
                    return false;
            }
        }
 
    }
}