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submodule
ffmpeg
Commits
a388ca35
Commit
a388ca35
authored
Aug 10, 2015
by
Clément Bœsch
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avfilter/sine: support expression in the number of output samples
parent
db18b3d6
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2 changed files
with
71 additions
and
4 deletions
+71
-4
filters.texi
doc/filters.texi
+26
-1
asrc_sine.c
libavfilter/asrc_sine.c
+45
-3
No files found.
doc/filters.texi
View file @
a388ca35
...
...
@@ -2857,7 +2857,26 @@ Specify the sample rate, default is 44100.
Specify the duration of the generated audio stream.
@item samples_per_frame
Set the number of samples per output frame, default is 1024.
Set the number of samples per output frame.
The expression can contain the following constants:
@table @option
@item n
The (sequential) number of the output audio frame, starting from 0.
@item pts
The PTS (Presentation TimeStamp) of the output audio frame,
expressed in @var{TB} units.
@item t
The PTS of the output audio frame, expressed in seconds.
@item TB
The timebase of the output audio frames.
@end table
Default is @code{1024}.
@end table
@subsection Examples
...
...
@@ -2878,6 +2897,12 @@ sine=f=220:b=4:d=5
sine=frequency=220:beep_factor=4:duration=5
@end example
@item
Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
pattern:
@example
sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
@end example
@end itemize
@c man end AUDIO SOURCES
...
...
libavfilter/asrc_sine.c
View file @
a388ca35
...
...
@@ -22,6 +22,7 @@
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/eval.h"
#include "libavutil/opt.h"
#include "audio.h"
#include "avfilter.h"
...
...
@@ -31,7 +32,8 @@ typedef struct {
const
AVClass
*
class
;
double
frequency
;
double
beep_factor
;
int
samples_per_frame
;
char
*
samples_per_frame
;
AVExpr
*
samples_per_frame_expr
;
int
sample_rate
;
int64_t
duration
;
int16_t
*
sin
;
...
...
@@ -61,6 +63,9 @@ typedef struct {
#define OPT_DUR(name, field, def, min, max, descr, ...) \
OPT_GENERIC(name, field, def, min, max, descr, DURATION, str, __VA_ARGS__)
#define OPT_STR(name, field, def, min, max, descr, ...) \
OPT_GENERIC(name, field, def, min, max, descr, STRING, str, __VA_ARGS__)
static
const
AVOption
sine_options
[]
=
{
OPT_DBL
(
"frequency"
,
frequency
,
440
,
0
,
DBL_MAX
,
"set the sine frequency"
),
OPT_DBL
(
"f"
,
frequency
,
440
,
0
,
DBL_MAX
,
"set the sine frequency"
),
...
...
@@ -70,7 +75,7 @@ static const AVOption sine_options[] = {
OPT_INT
(
"r"
,
sample_rate
,
44100
,
1
,
INT_MAX
,
"set the sample rate"
),
OPT_DUR
(
"duration"
,
duration
,
0
,
0
,
INT64_MAX
,
"set the audio duration"
),
OPT_DUR
(
"d"
,
duration
,
0
,
0
,
INT64_MAX
,
"set the audio duration"
),
OPT_
INT
(
"samples_per_frame"
,
samples_per_frame
,
1024
,
0
,
INT_MAX
,
"set the number of samples per frame"
),
OPT_
STR
(
"samples_per_frame"
,
samples_per_frame
,
"1024"
,
0
,
0
,
"set the number of samples per frame"
),
{
NULL
}
};
...
...
@@ -120,8 +125,25 @@ static void make_sin_table(int16_t *sin)
sin
[
i
+
2
*
half_pi
]
=
-
sin
[
i
];
}
static
const
char
*
const
var_names
[]
=
{
"n"
,
"pts"
,
"t"
,
"TB"
,
NULL
};
enum
{
VAR_N
,
VAR_PTS
,
VAR_T
,
VAR_TB
,
VAR_VARS_NB
};
static
av_cold
int
init
(
AVFilterContext
*
ctx
)
{
int
ret
;
SineContext
*
sine
=
ctx
->
priv
;
if
(
!
(
sine
->
sin
=
av_malloc
(
sizeof
(
*
sine
->
sin
)
<<
LOG_PERIOD
)))
...
...
@@ -136,6 +158,12 @@ static av_cold int init(AVFilterContext *ctx)
sine
->
sample_rate
+
0
.
5
;
}
ret
=
av_expr_parse
(
&
sine
->
samples_per_frame_expr
,
sine
->
samples_per_frame
,
var_names
,
NULL
,
NULL
,
NULL
,
NULL
,
0
,
sine
);
if
(
ret
<
0
)
return
ret
;
return
0
;
}
...
...
@@ -143,6 +171,8 @@ static av_cold void uninit(AVFilterContext *ctx)
{
SineContext
*
sine
=
ctx
->
priv
;
av_expr_free
(
sine
->
samples_per_frame_expr
);
sine
->
samples_per_frame_expr
=
NULL
;
av_freep
(
&
sine
->
sin
);
}
...
...
@@ -188,9 +218,21 @@ static int request_frame(AVFilterLink *outlink)
{
SineContext
*
sine
=
outlink
->
src
->
priv
;
AVFrame
*
frame
;
int
i
,
nb_samples
=
sine
->
samples_per_frame
;
double
values
[
VAR_VARS_NB
]
=
{
[
VAR_N
]
=
outlink
->
frame_count
,
[
VAR_PTS
]
=
sine
->
pts
,
[
VAR_T
]
=
sine
->
pts
*
av_q2d
(
outlink
->
time_base
),
[
VAR_TB
]
=
av_q2d
(
outlink
->
time_base
),
};
int
i
,
nb_samples
=
lrint
(
av_expr_eval
(
sine
->
samples_per_frame_expr
,
values
,
sine
));
int16_t
*
samples
;
if
(
nb_samples
<=
0
)
{
av_log
(
sine
,
AV_LOG_WARNING
,
"nb samples expression evaluated to %d, "
"defaulting to 1024
\n
"
,
nb_samples
);
nb_samples
=
1024
;
}
if
(
sine
->
duration
)
{
nb_samples
=
FFMIN
(
nb_samples
,
sine
->
duration
-
sine
->
pts
);
av_assert1
(
nb_samples
>=
0
);
...
...
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