Method and system for precise synchronization of audio and video streams during a distributed communication session with multiple participants
View Patent ↗Described are the architecture of such a system, algorithms for time synchronization during a multiway conferencing session, methods to fight with network imperfections such as jitter to improve synchronization, methods of introducing buffering delays to create handicaps for players with faster connections, methods which help players with synchronization (such as a synchronized metronome during a music conferencing session), methods for synchronized recording and live delivery of synchronized data to the audience watching the distributed interaction live over the Internet.
1. A computer implemented method for a selection of a time shift interval for smooth splicing wave fragment, the method for use in filling a gap in an audio signal, the method comprising:
minimizing a value calculated by a function
F
(
x
)
=
∑
i
=
0
L
W
c
+
i
-
W
c
+
i
-
x
·
[
1
+
P
(
L
-
i
)
2
(
1
+
sign
(
i
-
(
L
-
X
0
)
)
)
]
,
wherein xε[L,2L], c is a number of a plurality of samples on which a procedure of information recovery is invoked, W k is a value of a discreet approximation of a wave function on a sample k, L is a length of a “sound window” used to find a pre-granular sound fragment, x is a discreet wave shift, P is a weight function, Xo is a plurality of last received samples.
2. The method of claim 1 , wherein the weight function P is a function
P
n
(
i
)
=
∑
k
=
1
n
A
k
(
X
0
-
i
)
k
X
0
k
-
1
,
wherein A k is a constant.
3. A computer system operating as a component in a multi-way audio conferencing system audio pipeline architecture, the computer system including:
an audio buffer instantiated on the computer system, the audio buffer providing an audio signal;
a playout buffer module instantiated on the computer system, the playout buffer module operable to address gaps in the audio signal by execution of a signal smoothing action including:
for a selection of a time shift interval for smooth splicing a wave fragment, minimizing a value calculated by a function
F
(
x
)
=
∑
i
=
0
L
W
c
+
i
-
W
c
+
i
-
x
·
[
1
+
P
(
L
-
i
)
2
(
1
+
sign
(
i
-
(
L
-
X
0
)
)
)
]
,
wherein xε[L,2L], c is a number of a plurality of samples on which a procedure of information recovery is invoked, W k is a value of a discreet approximation of a wave function on a sample k, L is a length of a “sound window” used to find a pre-granular sound fragment, x is a discreet wave shift, P is a weight function, Xo is a plurality of last received samples.
4. The computer system of claim 3 , wherein the weight function P is a function
P
n
(
i
)
=
∑
k
=
1
n
A
k
(
X
0
-
i
)
k
X
0
k
-
1
,
wherein A k is a constant.
5. A computer system for determining a selection of a time shift interval for smooth splicing wave fragment, the determination for use in filling a gap in an audio signal, the computer system comprising:
means for minimizing a value calculated by a function
F
(
x
)
=
∑
i
=
0
L
W
c
+
i
-
W
c
+
i
-
x
·
[
1
+
P
(
L
-
i
)
2
(
1
+
sign
(
i
-
(
L
-
X
0
)
)
)
]
,
wherein xε[L,2L], c is a number of a plurality of samples on which a procedure of information recovery is invoked, W k is a value of a discreet approximation of a wave function on a sample k, L is a length of a “sound window” used to find a pre-granular sound fragment, x is a discreet wave shift, P is a weight function, Xo is a plurality of last received samples, and wherein the weight function P is a function
P
n
(
i
)
=
∑
k
=
1
n
A
k
(
X
0
-
i
)
k
X
0
k
-
1
,
wherein A k is a constant.