Transcribing MIDI Files and Recordings to Notation

If you use Composer to record your performance on a MIDI keyboard, Composer will automatically display your performance on the screen as music notation. The process by which Composer converts your performance into notation is called transcription..

When you import a MIDI file, Composer similarly transcribes the performance in the MIDI file to notation. The data stored in the MIDI file is basically a recording of what notes (pitches) are played at what exact times by various instruments (in tracks). The process that Composer uses to transcribe your performance at your music keyboard to notation is exactly the same transcription process that Composer uses to convert MIDI files to notation.

A good way to understand transcription is to think of the MIDI performance as a piano roll used on player pianos that were popular in the late 1800's and early 1900's. The holes in the piano roll determine what notes are played at what times. If you unroll the piano roll horizontally, you will observe that the holes mark the beginning and ending times of played notes. The vertical position of the holes determine the pitch of the notes.

Here is an example of a piano roll:

Basically, the above piano roll is all that Composer is given when it must transcribe your recording at the keyboard, or a MIDI file, to notation. Composer is able to cleverly transcribe the above piano roll information into notation. This example happens to be the Bach Minuet file, minuet.mid, that is installed in the C:\Program Files\MidiNotate Composer\Songs directory. The result of the transcription looks like this:

With Composer, you can see the Piano Roll Notation that underlies the notation. This is particularly useful when you want to edit the exact timing of notes without changing the notation. Here is what the above example looks like when you click the piano roll button in the main toolbar:

Composer must make many decisions about how to transcribe any given MIDI performance to notation. These decisions are similar to those that a trained musician would make when he or she hears music and writes down the notes on paper. (Very few musicians have this special training in "music dictation".)

Some decisions about how to transcribe the music are closely related to the style of the music. Composer does not attempt to determine what the style of music is, in order to make the appropriate decisions in transcribing the MIDI performance to notation. Instead, Composer lets you make a few simple choices about how to transcribe the music.

In particular, you can instruct Composer to:

     Choose one or the other of Standard versus Swing style in determining how to display rhythms such as illustrated here:

     Detect and display split upper and lower voices as opposed to single voice, as illustrated here:

     Remove overlapping notes in order to reduce the number of ties, as illustrated here:

     Remove rests smaller than some size you specify, such as a quarter rest, as illustrated here:

     Detect grace notes, trills, and tremelos.

The options described above are offered in the Transcription Options dialog described in the next topic. Composer offers you the opportunity to specify the transcription options in several circumstances:

     As you import a MIDI file, click the Transcription Options button in the File Open dialog box.

     As you download a MIDI file from the Internet, click the Transcription Options button in the File Save As dialog box.

     Before you record from your MIDI keyboard, choose the Transcription Options command in the Setup menu.

     When you use the Split Hands command, click the Transcription Options button in the Split Hands dialog box.

     When you use the Merge Tracks command, click the Transcription Options button in the Merge Tracks dialog box.

Also, after you have imported a MIDI file, or recorded a performance at your music keyboard, you can request Composer to transcribe the performance using a different set of transcription options, by using the Re-Transcribe command.

About Quantization

If you have used other music notation programs with a transcription feature, that feature very likely includes an option for specifying the "quantization level". Such an option tells the program to round note duration values and attack times to the nearest, say, thirty-second note, or sixteenth note. You may wonder why such an option is missing in Composer. The reason is that Composer has a better way of determining note durations and attack times than simply rounding to some nearest value. Such quantization only works well for fairly simple rhythms. Notes with long values tend to be "over-enthusiastically" notated with extra dotted values and ties. Separate notes with short values and small differences in attack times may be incorrectly collapsed into chords. Composer does a much better job at transcribing rhythms than notation programs that use a simple quantization approach. Composer analyzes the rhythmic context of each note to determine what quantization level to apply to the note.

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