Desktop

Ask something
Discussion Locked

Musical Instrument Digital Interface

0 helpful
5 replies

by baffled

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

How do we create a MIDI sequence audio file? Can one convert a MP3. WAV or WMA audio file to MIDI? My interest lies in MIDI relative small size audio file which allows to sound formatted in emails easily and doesn't take up much space.

Your information will be much appreciated & THANKS!!

5 replies

by thechas

This is a 'GROSS' simplification, but think of MIDI sequence files as being similar to player piano roles.

A MIDI file tells an electronic instrument what notes to play when.

As you add instruments, the file gets larger.

That said, here aresome 'general' MIDI links for you.

http://tinyurl.com/54sa

http://www.midi.com/

http://www.magix.com/select.html

http://www.musiq.com/recording/digaudio/

http://www.syntrillium.com/cooledit/

http://progweed.echoechoplus.com/

http://home.att.net/~audiocompositor/

http://www.newmusictools.com/nmt1/index.html

http://home.bip.net/baxtrom/soliton.htm

http://www.rmbsoft.com/

http://www.sound-recorder.com/index.html

Chas

by guruofdos

Midi, as The Chas says, is a set of instructions that tell a MIDI enabled instrument, or midi synth on the soundcard, to play notes in a given sequence. WAVS are actual waveforms that are converted to sound by your speakers. With midi files, there are no waveforms in the file...these are provided by the soundcard or instrument.

A typical audio signal has a frequency range of 20Hz to 20KHz, and to 'sample' this range of frequencies, the sample rate must be at least double the highest frequency. A typical sample rate for audio is 44.1kHz or so. The level of the audio waveform is stored as a binary number, the number of bits giving the number of discreet values that can be represented. 8 bit resolution gives 256 levels, and 16 bit resolution gives 65536 levels. The higher the resolution, the better the accuracy or quantisation of the original sound. So, a stereo source, sampled at 44.1k with 16 bit resolution needs 44100 x 2 x 2 bytes per second of audio in its rawest form, or approximately 176 kilobytes. MP3 and other forms of compression use algorythms to reduce the file size, but the greater the compression, the less detail can be stored.

With midi, the instrument sound samples are stored in ROM and the midi file just tellsthe instrument which samples to play at a given time...the samples are not embedded into the file. Hence MIDI files are just a few Kb in size. This also explains why you don't get any vocals in MIDI!!!!

This discussion is closed to new replies.