how to extract and convert audio file formats

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How to extract and convertaudio file formats

This article describes anAll-In-One Code Framework sample that is available for download. The sample demonstrates how to extract and convert audiofile formats, which include wav, mp3 and mp4 files.

 

The sample is used to extractmusic file formats. We usually play music with Windows Media Player or othermusic-playing software. If we find our favorite music clip, we can use thefunction of this sample to extract it and convert it into another file format.All technology mentioned above is based on Expression Encoder SDK 4.0. When youinstall Expression Encoder 4.0, you can use Visual Studio 2010 to add areference to it. In this way, you don't have to install the SDK installationkits individually.

 

The sample uses ExpressionEncoder SDK 4 to output *.mp4 or *.wma file. The .mp3 audio format is currentlynot supported as output format in Expression Encoder 4.

Difficulty Level

Medium

Technicaloverview

 

1.        Usefollowing helper function to cut the audio file from startpoint to endpoint,and output the clip as the selected audio format. 

 

public static string ExtractAudio(string sourceAudioFile, string outputDirectory,

        OutputAudioType outputAudioType, double startpoint, double endpoint)

    {

        using (Job job = new Job())

        {

            MediaItem src = new MediaItem(sourceAudioFile);

            switch (outputAudioType)

            {

                case OutputAudioType.MP4:

                    src.OutputFormat = new MP4OutputFormat();

                    src.OutputFormat.AudioProfile = new AacAudioProfile();

                    src.OutputFormat.AudioProfile.Codec = AudioCodec.AAC;

                    src.OutputFormat.AudioProfile.BitsPerSample = 24;

                    break;

                case OutputAudioType.WMA:

                    src.OutputFormat = new WindowsMediaOutputFormat();

                    src.OutputFormat.AudioProfile = new WmaAudioProfile();

                    src.OutputFormat.AudioProfile.Bitrate = new VariableConstrainedBitrate(128, 192);

                    src.OutputFormat.AudioProfile.Codec = AudioCodec.WmaProfessional;

                    src.OutputFormat.AudioProfile.BitsPerSample = 24;

                    break;

            }

 

            TimeSpan spanStart = TimeSpan.FromMilliseconds(startpoint);

            src.Sources[0].Clips[0].StartTime = spanStart;

            TimeSpan spanEnd = TimeSpan.FromMilliseconds(endpoint);

            src.Sources[0].Clips[0].EndTime = spanEnd;

 

            job.MediaItems.Add(src);

            job.OutputDirectory = outputDirectory;

            job.Encode();

 

            return job.MediaItems[0].ActualOutputFileFullPath;

        }

    }

 

2.        Use the Windows Media Player control to play thesource audio file. The following MSDN article introduces how to embed theWindows Media Player ActiveX control in a Windows Form. http://msdn.microsoft.com/en-us/library/dd562851.aspx

 

For more information about how to create and deploy thesample application, see the Readme.txt file that is included in the downloadpackage.

Technologycategory

Network

Languages

   

Language

    

Project Name

     

Visual C#

    

CSExtractAudioFile

     

Visual Basic.NET

    

VBExtractAudioFile

 

 

Prerequisites

Thissample application was created by using Visual Studio 2010, .NETFramework 4 and Microsoft Expression Encoder 4.

References

 

Expression Encoder SDKProgramming Reference

http://msdn.microsoft.com/en-us/library/ff396833(v=Expression.40).aspx

 

 

Microsoft Expression Encoder 4FAQ

http://social.expression.microsoft.com/Forums/en/encoder/thread/3eabf903-b49f-4f92-b508-f28a795d6c90