<s>
Apprentice	B-Language
Video	I-Language
is	O
a	O
cross-platform	B-Operating_System
open-source	B-Application
media	O
player	O
,	O
developed	O
as	O
a	O
personal	O
project	O
by	O
Pavel	O
Koshevoy	O
since	O
May	O
29	O
,	O
2010	O
.	O
</s>
<s>
It	O
is	O
similar	O
to	O
other	O
media	O
players	O
like	O
VLC	B-Application
or	O
MPC-HC	B-Language
,	O
but	O
offers	O
a	O
few	O
features	O
absent	O
from	O
those	O
players	O
(	O
alpha	O
channel	O
preview	O
,	O
timeline	O
looping	O
in/out	O
points	O
,	O
and	O
several	O
options	O
for	O
achieving	O
adequate	O
video	O
playback	O
performance	O
on	O
outdated	O
slow	O
hardware	O
)	O
.	O
</s>
<s>
The	O
code	O
base	O
is	O
written	O
in	O
C++	B-Language
using	O
Qt	B-Language
frameworks	I-Language
for	O
the	O
user	O
interface	O
,	O
FFmpeg	B-Library
libraries	O
for	O
demuxing	O
and	O
decoding	O
of	O
audio/video	O
,	O
Portaudio	B-Language
for	O
audio	O
rendering	O
,	O
OpenGL	B-Application
for	O
video	O
rendering	O
,	O
and	O
Libass	B-Language
for	O
rich	O
subtitle	O
rendering	O
.	O
</s>
<s>
Apprentice	B-Language
Video	I-Language
source	O
code	O
is	O
freely	O
available	O
under	O
the	B-License
MIT	I-License
license	I-License
.	O
</s>
<s>
The	O
audio	O
tempo	O
scaling	O
filter	O
developed	O
for	O
Apprentice	B-Language
Video	I-Language
was	O
ported	O
to	O
C	O
and	O
contributed	O
to	O
FFmpeg	B-Library
as	O
atempo	O
filter	O
.	O
</s>
