X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=include%2Fclip-stretch-options.html;h=1b461a853639c185770d30150ce0016332b980a1;hb=71afa472a61c8d63fb8932c06b3ab83bf3aecbda;hp=04753b9537d5fb71958418ea748d0778254c392f;hpb=5b86e5a46b9c22c955753f1f24ae611bec7ae9b1;p=ardour-manual diff --git a/include/clip-stretch-options.html b/include/clip-stretch-options.html index 04753b9..1b461a8 100644 --- a/include/clip-stretch-options.html +++ b/include/clip-stretch-options.html @@ -1,11 +1,32 @@ -
FIXME. Optional. What happens when disabled? Wonât match the current timeline -tempo: START THE SECTION WITH THIS: ARDOUR ALWAYS MATCHES CURRENT SESSION -TEMPO, SO TEMPO RAMPS WILL WORK FOR CLIPS
++ When you load an audio clip into a trigger slot, Ardour applies some + heuristics to estimate its temo in beats per minute. Unless a metadata + in the file source provides information, + minibpm is used + to analyze and detect the file's BPM. +
+ ++ After tempo is estimated, the clip is time-stretched to match the + session's tempo map. This means that should session's tempo change over + time (in either ramped or constant mode), all audio clips will be + re-stretched to accomodate for that. +
+ ++ Disabling stretching when original clip's tempo doesn't match that of the + session will most of the times make the clip audibly go out of sync with + the beat. +
Stretch modes:
++ Once stretching is enabled, you have several options how to apply it: +
++ This is where the estimated tempo is displayed. It can also + be progressively divided or mutiplied by two. +
-+ Supposing, session's tempo is currently 120bpm and original clip's tempo + is 90bpm. Stretching the clip to match session's tempo will make it sound + faster that it originally is. +
-Itâs a hint to help you counting. FIXME
++ If the estimated clip's tempo is divided by 2, stretching the resulted + 45bpm back to 120bpm will make the clip sound faster. Vice versa, + multiplying the original clip's tempo by 2 and then stretching it down + from 180bpm to 120bpm will make the clip sound slower than it originally is. +
-1) when a file is loaded, we infer its bpm either by minibpm's estimate, a flag in the filename, metadata (TBD) or other means
- -2) we assume the clip must have an integer number of beats in it (simplest case is a one-bar loop with 4 beats in it)
- -3) ...so we round to the nearest beat length, and set the tempo to *exactly* fit the sample-length into the assumed beat-length
- -4) the user may recognize a problem: "this was a 3/4 beat, which was rounded to 4 beats but it should have been 3"
+5) if the user changes the beat-length, then the tempo is recalculated for use during stretching
++ This control allows adjusting the estimated tempo in a finer manner, + by changing the amount of beats it takes to play the clip in the selected + trigger slot. The change is immediately displayed in the BPM field above. +
-6) someday, we will also allow the sample start and length to be adjusted in a trimmer, and that will also adjust the tempo
+7) in all cases the user should be in final control; but our "internal" value for stretching are just sample-start and BPM, end of story
\ No newline at end of file ++ This is an estimate of the clip's length as measured in bars for two + popular time signatures: 4/4 and 3/4. +