Scrubbing and Seeking

PRL 08Jun15: There is no mention of scroll-seeking with shift key down, in which the length of skips is determined by mouse position relative to the midline, the skipping speed is displayed with an X, and play is normal (or normal speed reversed) when the pointer is near the middle. Also, would images of all the various styles and colors of speed numbers be useful?

Peter 08Jun15: ToDo-2R Ready for review and merciless editing. I'm finding it much harder to describe than actually do.

• Bill 15Jun2015:
  • Substantial changes to the Scrubbing section:
    • change "cursor" to "pointer" when we are referring to thing that follows mouse motions
    • note that you can release the mouse button after CRTL + left-click to get into scrubbing mode
    • note that nothing happens after CTRL + left-click until you move the mouse pointer
    • note that editing cursor remains at its original position after stopping scrubbing with Stop button or spacebar
    • note that you can mark the "found position" with a simple left-click only if scrubbing is stopped while the green play head is over the mouse pointer.
  • in Seeking
    • move sentence from end of scrubbing to beginning of seeking section
    • add sentence noting that simple left-click will quickly move you to that position in the waveform
  • in Scroll-scrub
    • change "cursor" to "pointer" as above

Scrubbing is the action of dragging the cursor across a segment of the waveform to hear it - a convenient way to quickly navigate an audio file and find a particular piece of audio.

Once you have placed Audacity in scrub play mode it will remain in that mode until you Stop and return to normal play mode.

The term comes from the early days of the recording industry and refers to the process of physically turning tape reels to move the tape past the play-head to locate a specific point in the audio track.

Scrubbing

Scrubbing works only in Select tool mode.

Pressing CTRL + left-click will put you into scrub play mode. You can now release the mouse button then move the pointer right and left across the waveform. This will cause Audacity to scrub play forward or backward from the point at which you clicked in the waveform. Nothing will happen until you move the mouse pointer. Scrub play will temporarily stop when the green playback cursor (the "play-head") catches up with the mouse pointer but will restart again as soon as you move the mouse left or right.

The speed of the scrub play can be controlled by rotating the mouse wheel (if your mouse is so equipped). Each four steps of the rotated mouse wheel doubles, or halves, the speed - which is equivalent to one octave. The scrub speed will be shown, in yellow-ochre, superimposed on the waveform display when you change it with mouse wheel.

It is possible to zoom while you are scrubbing by holding the CTRL key down and rotating the mouse wheel.

Clicking the Stop button (or its shortcut Space) at any time will stop scrub play and return you to normal play mode. Note that at this point the editing cursor will be at the position is was when scrubbing was started. If you stop scrubbing when the green playback cursor is over the mouse pointer then the scrubbing position can be marked with a left-click mouse gesture which moves the cursor to that position; you may then use CTRL + B to create a marker label at that point.

You can invoke scrub play while audio is playing normally and it will abandon the playback to perform the scrub play. You cannot invoke scrub play while you are recording or paused in recording mode.

Seeking

If you hold the left mouse button down as you scrub the scrubbing will change to seeking.

In seek mode many small slices of the audio are played at normal speed and always something very close to the mouse cursor enabling you to move across the audio rapidly. This is similar to using the seek button on a CD player.

Releasing the left mouse while you are seeking will return you to scrub play and pressing it again will return you to seek play enabling you to repeatedly press and release the left mouse button to switch between seeking and scrubbing.

Note that a simple left-click anywhere in the waveform while in scrubbing mode will immediately seek to that position, then re-enter scrubbing mode.

Scroll-scrub

PRL 28May15: ToDo-2 Needs a cross reference to "Enable Scrolling left of zero" on this page http://manual.audacityteam.org/man/Tracks_Preferences

Peter 21May15: ToDo-2 we have, as yet no proper nomenclature for this type of scrubbing. I think Paul calls it double-click scrubbing.

• Peter 04Jun15: In the latest UI Paul now calls the "Scroll-scrub", in the Prefs>Mouse. Accordingly I have retitled this H2 section to reflect the nomenclature used in the GUI.

If you CTRL + double-left-click then move the mouse pointer to scrub, the green play cursor (effectively the "play-head") remains at the mid-position of the waveform display and the speed of scrubbing can be varied much more smoothly by the position of the mouse cursor. In this mode the mouse cursor position does not determine the target of the scrub rather it determines the speed of the scrub, the further away from the play cursor (in either direction) the faster the speed of the scrub. The scrub speed will be shown, in green, superimposed on the waveform display as you drag the cursor with the mouse.

The speed of the Scroll-scrub play can also be controlled by rotating the mouse wheel (if your mouse is so equipped). The Scroll-scrub speed will be shown, in green, superimposed on the waveform display when you change it with mouse wheel.

Mac OS X users: CTRL = COMMAND. So, for example, CTRL + left-click = COMMAND + left-click