Editing MIDI timecode (section)

=== Quarter-frame messages ===
When the time is running continuously, the 32-bit time code is broken into 8 4-bit pieces, and one piece is transmitted each quarter frame.  I.e. 96—120 times per second, depending on the frame rate. Since it takes eight quarter frames for a complete time code message, the complete SMPTE time is updated every two frames. A quarter-frame message consists of a status byte of 0xF1, followed by a single 7-bit data value: 3 bits to identify the piece, and 4 bits of partial time code.  When time is running forward, the piece numbers increment from 0–7; with the time that piece 0 is transmitted is the coded instant, and the remaining pieces are transmitted later.

If the MIDI data stream is being rewound, the piece numbers count backward.  Again, piece 0 is transmitted at the coded moment.

The time code is divided little-endian as follows:
{|class="wikitable"
|+MIDI time code pieces
! Piece # || Data byte || Significance
|-
! 0
| <code>0000&thinsp;ffff</code> || Frame number lsbits
|-
! 1
| <code>0001&thinsp;000f</code> || Frame number msbit
|-
! 2
| <code>0010&thinsp;ssss</code> || Second lsbits
|-
! 3
| <code>0011&thinsp;00ss</code> || Second msbits
|-
! 4
| <code>0100&thinsp;mmmm</code> || Minute lsbits
|-
! 5
| <code>0101&thinsp;00mm</code> || Minute msbits
|-
! 6
| <code>0110&thinsp;hhhh</code> || Hour lsbits
|-
! 7
| <code>0111&thinsp;0rrh</code> || Rate and hour msbit
|}