def managed_transition_helper(track1, track2, state, xfade=0, itrim1=0.0, otrim1=0.0, itrim2=0.0, maxlen=None, mode='equal_power', audition_hack=False):
"""Manage the transition from one track to another
Most of the parameters should be provided by keyword (in Py3, there'd be * after state).
state: State mapping - cursor position etc is maintained here
xfade: Number of tatums/segments to crossfade over
itrim1: Initial trim of first track - ignored unless starting fresh
otrim1: Trim end of first track - all these are floating-point seconds
itrim2: Trim beginning of second track
maxlen: If set, mix duration will be capped to this (protect against over-long transition)
mode: Either equal_power or linear
audition_hack: If set, cursor position will be reduced by the fade length. Yep, it's a hack.
"""
if "cursor" not in state:
state["cursor"] = 0
log.info("Cursor NOT IN STATE.")
else:
log.info(state)
for track in (track1, track2):
loudness = track.analysis.loudness
track.gain = db_2_volume(loudness)
# NOTE: All values are floating-point seconds, save xfade which is a number
# of tatums/segments (assumed to be at average length).
t1start = first_viable(track1) + itrim1
t1end = last_viable(track1) - otrim1
t2start = first_viable(track2) + itrim2
# offset between start and first theoretical beat.
t2offset = lead_in(track2)
if xfade == 0:
# Ensure that we always crossfade at least a little bit
fade = 0.0001
# Don't allow difference between track start and first beat to prevent hard transition.
t2offset = 0
else:
# The crossfade is defined based on the tempo at the end
# of the song, and we fade across X tatums/segments.
avg_duration = avg_end_duration(track1)
fade = avg_duration * xfade
if audition_hack:
log.debug(state['cursor'])
state['cursor'] -= fade
log.debug("Audition hack")
log.debug(state['cursor'])
playback_end = t1end - fade - t2offset
playback_duration = playback_end - state['cursor']
mix_duration = t1end - playback_end
log.info(mix_duration)
if maxlen is not None:
# Protect from xfade longer than second track.
while mix_duration > maxlen:
# Chop half a second at a time (not sure why, but let's maintain it for now)
mix_duration -= .5
playback_end += .5
playback_duration += .5
pb1 = pb(track1, state['cursor'], playback_duration)
pb2 = cf((track1, track2), (playback_end - .01, t2start), mix_duration, mode=mode)
state['cursor'] = mix_duration + t2start
return [pb1, pb2]
def managed_transition(track1, track2, xfade=0, otrim=0.0, itrim=0.0):
state = {"cursor": track1.analysis.duration - 6.0 - float(otrim)}
ret = managed_transition_helper(track1, track2, state,
xfade=int(xfade),
otrim1=float(otrim),
itrim2=float(itrim),
maxlen=float(track2.analysis.duration),
audition_hack=True,
)
ret.append(pb(track2, state['cursor'], 6))
print("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!")
print(ret)
return ret
def format_track(track, itrim=0.0, otrim=0.0, fadeout=5):
playback = pb(track, itrim, track.analysis.duration - otrim)
fade = fo(track, track.analysis.duration - otrim, fadeout)
return [playback, fade]
