Matching
sound
to
picture
is
accomplished
with
the
same
techniques
as
editing
a
work
print.
This
is
exactly
why
the
picture
is
considered
locked.
If
you
start
cutting
the
audio
to
match
the
picture,
all
you
need
is
the
editor
making
subsequent
edits
to
throw
all
of
your
sound
edits
out
of
sync.
Tape
splices
are
made
to
the
mag-track
-
as
if
it
were
film,
between
frames
(except
the
cuts
are
diagonal),
using
a
splicing
block
-
NOT
a
hot
splicer.
This
is
because
there
are
4
perfs
to
a
frame
of
35mm
film
and
a
pref
between
each
frame
of
16mm
film.
When
a
length
of
mag-track
is
out
of
sync
with
the
picture,
"frames"
(counted
by
the
number
of
perfs
to
a
frame)
are
either
spliced
out
or
spliced
in
to
take-in
or
let-out
the
lag
in
the
sound
so
it
conforms
to
the
picture.
The
silent
inserts
in
your
audio
are
smoothed
over
with
a
separate
"room
noise"
or
ambience
track,
recorded
silence
(or
subtle
roar
on
a
set
that
wasn't
quite
as
silent
as
you
might
have
thought!).
It
must
be
kept
in
mind
that
if
500
frames
of
picture
pass
your
viewer,
exactly
500
frames
of
mag-track
must
simultaneously
pass
with
the
film
to
keep
the
sound
in-sync
with
the
picture.
If
a
movie
has
172,800
frames
of
picture,
the
mag-track
must
also
be
a
matching
172,800
frames
in
length.
