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A chunk begins with the chunk type , a four-byte string whose value is either MThd for a header chunk or MTrk for a track chunk. The chunk length follows this string, and indicates the number of bytes remaining in the chunk. The chunk length is a 32-bit unsigned integer in big-endian format, i.e., the most-significant byte is first.

Header chunk

The header chunk begins with the string MThd , and is followed by a fixed chunk length value of 6; as a 32-bit unsigned integer this is 0x00_00_00_06.

The file type follows, and is a 16-bit unsigned integer that takes on one of three possible values: 0 (0x00_00) indicates single track data, 1 (0x00_01) indicates multi-track data which is vertically synchronous (i.e., they are parts of the same song), and 2 (0x00_02) indicates multi-track data with no implied timing relationship between tracks. Type 1 is by far the most common, where each track contains MIDI messages on a single channel. In this way tracks can be associated with a single instrument and recorded individually

Next is the number of tracks , a 16-bit unsigned integer. The number of tracks can range from one (0x00_01) to 65,535 (0xFF_FF). In practice the number of tracks is typically about 20 or so.

The last value in the header chunk is the division , a 16-bit unsigned integer that indicates the number of ticks per quarter note . The tick is a dimensionless unit of time, and is the smallest grain of time used to indicate the interval between events. A typical value of division is 120 (0x00_78).

Track chunk

The track chunk begins with the string MTrk , and is followed by the track length , a 32-bit unsigned integer that indicates the number of bytes remaining in the track. In theory a track could be as long as 4 Gbytes!

The remainder of the track is composed of pairs of delta-times and events. A delta-time is in units of tics, and indicates the time interval between events. An event is either a MIDI message or a meta-event . Meta-events are unique to the standard MIDI file, and indicate information such as track name, tempo, copyright notice, lyric text, and so on.

A delta time uses variable-length format ( VLF ), and can be anywhere from one to four bytes in length. Short delta times require only one byte, and long delta times can require up to four bytes. Since short delta times tend to dominate the standard MIDI file (think of a chord hit that generates a burst of Note-On messages with very little time between events), most of the delta times are only one byte long and the overall file size is thus minimized. However, since very long delta times must be accommodated as well, the variable-length format can use up to four bytes to represent very long time intervals.

Variable-length format

Variable-length format ( VLF ) is used to represent delta times and the length of meta-events (to be described below). A numerical value represented in VLF requires from one to four bytes, depending on the size of the numerical value. Since the standard MIDI file is parsed one byte at a time, some type of scheme is required to let the parser know the length of the VLF number. A naïve approach would be to include an additional byte at the beginning of the VLF to indicate the number of bytes remaining in the value. However, this approach would mean that a delta time always requires a minimum of two bytes. Instead, the VLF uses the most-significant bit (MSB) as a flag to indicate whether more bytes follow.

Questions & Answers

how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Musical signal processing with labview -- midi for synthesis and algorithm control. OpenStax CNX. Nov 09, 2007 Download for free at http://cnx.org/content/col10487/1.2
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