[The Scientist (OP)]

Please elaborate upon explanation. Thanks!

[RD]

MP3 is type of audio file, (in a lossy compression format): MP3 is a (compressed) digital a recording of sound.

MIDI files do not contain an audio file, they do not contain a recording of sound.
MIDI files are the computer equivalent of sheet music: they contain the instructions on how to play the tune, a tune which could be played by a wide range of (computer generated) instruments.

[Geezer]

Because of the differences that RD identified, MIDI files are incredibly small compared to MP3 files.

Arguably, MIDI files are just another form of lossy compression, although it is rather extreme.

[libbypetter]

MP3 is a recording file which your computer play like a tape where MIDI is piece of music which will read by computer and play on a virtual piano.MP3 is one of the widely used file format.

[daniel45]

A MIDI file is software for representing musical information in a digital format. However, Mp3 is a patented encoding format for digital audio. Also, MIDI is always lighter than Mp3 even if you convert a large Mp file into MIDI you will get way lighter size than Mp3 one.

[chris]

A MIDI file is software for representing musical information in a digital format.

I don't really follow this argument. Can you explain this a bit more clearly?

[daniel45]

A MIDI file is software for representing musical information in a digital format.

I don't really follow this argument. Can you explain this a bit more clearly?

Midi files are nothing more than a set of instructions that tell your keyboard or other sound source what to do. They are easily edited, transposed, etc.
There is a more or less accepted format for them, called General Midi, where certain sounds or groups of sounds are assigned to selected channels. For example drums are on 10, and sometimes 9, bass on 2, lead instrument, if any, is on 4 etc. It is not mandatory to use the GM format, but it makes it easier to work with if you have an idea of what sounds will be called up from what channels.
There are also expanded formats such as Yamaha's XG, Korg's GS... that are tailored to work best with their sound banks.
There are lots of better explanations on the internet, but this should give you an idea.
MP3s are compressed recordings of sounds. Some instruments can now transpose them to a degree. They really can't be edited though. The sounds that were originally recorded are what you get! WAV format is where most of them start, and they are compressed by the MP3 format to save space, since WAV files are really large in comparison. If you use a fairly high MP3 rate of compression, say 320, then it's hard for most ears to tell the difference in sound from the original file.
I record most of my performances in WAV format, then, if I wish to share them over the internet, compress them into MP3s. There are lots of free programs to convert them from WAV to MP3. They cannot be converted the other way to regain the original quality, so I always save the original recording in case I want to burn it to CD and get the best quality sound.
Hope this helps.

[evan_au]

A MIDI file is software for representing musical information in a digital format.

I don't really follow this argument. Can you explain this a bit more clearly?

You could compare MIDI to the roll of paper in an old player piano.
- The holes contains information about which note to strike, and when - this allows you to play a tune
- MIDI is a digital equivalent, with the information stored as digital bytes rather than holes in paper.
- MIDI adds extra channels for drums and other instruments.
- And more information about how hard to strike the note
- It records data like "at 23.1 seconds into the track, strike middle C, moderately hard"
- It is intended to capture and replay musical instruments, not human speech, jet planes, etc
See: https://en.wikipedia.org/wiki/Piano_roll#In_digital_audio_workstations

However, MP3 could be compared to a cassette tape - it records which frequencies appeared, how fast they appeared, how slowly they decayed, and how loud they got in-between.
- It has right & left stereo channels, but doesn't separate out different instruments
- It records data like "at 23.1 seconds into the track, play 262Hz at -40dB and 525Hz at -50dB,
then 5ms later, play lay 262Hz at -35dB and 525Hz at -45dB...." and so on, at very fine time granularity until the note fades out at 25.3 seconds
- It capture and replay musical instruments, human speech, jet planes, etc with equal ease

MIDI takes a lot less space than an MP3 file.
https://en.wikipedia.org/wiki/MIDI
https://en.wikipedia.org/wiki/MP3

[stanbostock]

Have you got useful information from this thread?

[stevewilliam007]

It is really a helpful post.