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Linshizhi
ffmpeg.wasm-core
Commits
5980e57c
Commit
5980e57c
authored
Aug 18, 2012
by
Nicolas George
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lavfi: add volumedetect filter.
parent
13b965ea
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5 changed files
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202 additions
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-0
Changelog
Changelog
+1
-0
filters.texi
doc/filters.texi
+40
-0
Makefile
libavfilter/Makefile
+1
-0
af_volumedetect.c
libavfilter/af_volumedetect.c
+159
-0
allfilters.c
libavfilter/allfilters.c
+1
-0
No files found.
Changelog
View file @
5980e57c
...
@@ -50,6 +50,7 @@ version next:
...
@@ -50,6 +50,7 @@ version next:
- edge detection filter
- edge detection filter
- framestep filter
- framestep filter
- ffmpeg -shortest option is now per-output file
- ffmpeg -shortest option is now per-output file
- volume measurement filter
version 0.11:
version 0.11:
...
...
doc/filters.texi
View file @
5980e57c
...
@@ -690,6 +690,46 @@ volume=-12dB
...
@@ -690,6 +690,46 @@ volume=-12dB
@end example
@end example
@end itemize
@end itemize
@section volumedetect
Detect the volume of the input video.
The filter has no parameters. The input is not modified. Statistics about
the volume will be printed in the log when the input stream end is reached.
In particular it will show the mean volume (root mean square), maximum
volume (on a per-sample basis), and the beginning of an histogram of the
registered volume values (from the maximum value to a cumulated 1/1000 of
the samples).
All volumes are in decibels relative to the maximum PCM value.
Here is an excerpt of the output:
@example
[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
[Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
[Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
[Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
[Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
[Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
[Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
[Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
[Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
@end example
It means that:
@itemize
@item
The mean square energy is approximately -27 dB, or 10^-2.7.
@item
The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
@item
There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
@end itemize
In other words, raising the volume by +4 dB does not cause any clipping,
raising it by +5 dB causes clipping for 6 samples, etc.
@section asyncts
@section asyncts
Synchronize audio data with timestamps by squeezing/stretching it and/or
Synchronize audio data with timestamps by squeezing/stretching it and/or
dropping samples/adding silence when needed.
dropping samples/adding silence when needed.
...
...
libavfilter/Makefile
View file @
5980e57c
...
@@ -67,6 +67,7 @@ OBJS-$(CONFIG_PAN_FILTER) += af_pan.o
...
@@ -67,6 +67,7 @@ OBJS-$(CONFIG_PAN_FILTER) += af_pan.o
OBJS-$(CONFIG_RESAMPLE_FILTER)
+=
af_resample.o
OBJS-$(CONFIG_RESAMPLE_FILTER)
+=
af_resample.o
OBJS-$(CONFIG_SILENCEDETECT_FILTER)
+=
af_silencedetect.o
OBJS-$(CONFIG_SILENCEDETECT_FILTER)
+=
af_silencedetect.o
OBJS-$(CONFIG_VOLUME_FILTER)
+=
af_volume.o
OBJS-$(CONFIG_VOLUME_FILTER)
+=
af_volume.o
OBJS-$(CONFIG_VOLUMEDETECT_FILTER)
+=
af_volumedetect.o
OBJS-$(CONFIG_AEVALSRC_FILTER)
+=
asrc_aevalsrc.o
OBJS-$(CONFIG_AEVALSRC_FILTER)
+=
asrc_aevalsrc.o
OBJS-$(CONFIG_ANULLSRC_FILTER)
+=
asrc_anullsrc.o
OBJS-$(CONFIG_ANULLSRC_FILTER)
+=
asrc_anullsrc.o
...
...
libavfilter/af_volumedetect.c
0 → 100644
View file @
5980e57c
/*
* Copyright (c) 2012 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/audioconvert.h"
#include "libavutil/avassert.h"
#include "audio.h"
#include "avfilter.h"
#include "internal.h"
typedef
struct
{
/**
* Number of samples at each PCM value.
* histogram[0x8000 + i] is the number of samples at value i.
* The extra element is there for symmetry.
*/
uint64_t
histogram
[
0x10001
];
}
VolDetectContext
;
static
int
query_formats
(
AVFilterContext
*
ctx
)
{
enum
AVSampleFormat
sample_fmts
[]
=
{
AV_SAMPLE_FMT_S16
,
AV_SAMPLE_FMT_S16P
,
AV_SAMPLE_FMT_NONE
};
AVFilterFormats
*
formats
;
if
(
!
(
formats
=
ff_make_format_list
(
sample_fmts
)))
return
AVERROR
(
ENOMEM
);
ff_set_common_formats
(
ctx
,
formats
);
return
0
;
}
static
int
filter_samples
(
AVFilterLink
*
inlink
,
AVFilterBufferRef
*
samples
)
{
AVFilterContext
*
ctx
=
inlink
->
dst
;
VolDetectContext
*
vd
=
ctx
->
priv
;
int64_t
layout
=
samples
->
audio
->
channel_layout
;
int
nb_samples
=
samples
->
audio
->
nb_samples
;
int
nb_channels
=
av_get_channel_layout_nb_channels
(
layout
);
int
nb_planes
=
nb_planes
;
int
plane
,
i
;
int16_t
*
pcm
;
if
(
!
av_sample_fmt_is_planar
(
samples
->
format
))
{
nb_samples
*=
nb_channels
;
nb_planes
=
1
;
}
for
(
plane
=
0
;
plane
<
nb_planes
;
plane
++
)
{
pcm
=
(
int16_t
*
)
samples
->
extended_data
[
plane
];
for
(
i
=
0
;
i
<
nb_samples
;
i
++
)
vd
->
histogram
[
pcm
[
i
]
+
0x8000
]
++
;
}
return
ff_filter_samples
(
inlink
->
dst
->
outputs
[
0
],
samples
);
}
#define MAX_DB 91
static
inline
double
logdb
(
uint64_t
v
)
{
double
d
=
v
/
(
double
)(
0x8000
*
0x8000
);
if
(
!
v
)
return
MAX_DB
;
return
log
(
d
)
*
-
4
.
3429448190325182765112891891660508229
;
/* -10/log(10) */
}
static
void
print_stats
(
AVFilterContext
*
ctx
)
{
VolDetectContext
*
vd
=
ctx
->
priv
;
int
i
,
max_volume
,
shift
;
uint64_t
nb_samples
=
0
,
power
=
0
,
nb_samples_shift
=
0
,
sum
=
0
;
uint64_t
histdb
[
MAX_DB
+
1
]
=
{
0
};
for
(
i
=
0
;
i
<
0x10000
;
i
++
)
nb_samples
+=
vd
->
histogram
[
i
];
av_log
(
ctx
,
AV_LOG_INFO
,
"n_samples: %"
PRId64
"
\n
"
,
nb_samples
);
if
(
!
nb_samples
)
return
;
/* If nb_samples > 1<<34, there is a risk of overflow in the
multiplication or the sum: shift all histogram values to avoid that.
The total number of samples must be recomputed to avoid rounding
errors. */
shift
=
av_log2
(
nb_samples
>>
33
);
for
(
i
=
0
;
i
<
0x10000
;
i
++
)
{
nb_samples_shift
+=
vd
->
histogram
[
i
]
>>
shift
;
power
+=
(
i
-
0x8000
)
*
(
i
-
0x8000
)
*
(
vd
->
histogram
[
i
]
>>
shift
);
}
if
(
!
nb_samples_shift
)
return
;
power
=
(
power
+
nb_samples_shift
/
2
)
/
nb_samples_shift
;
av_assert0
(
power
<=
0x8000
*
0x8000
);
av_log
(
ctx
,
AV_LOG_INFO
,
"mean_volume: %.1f dB
\n
"
,
-
logdb
(
power
));
max_volume
=
0x8000
;
while
(
max_volume
>
0
&&
!
vd
->
histogram
[
0x8000
+
max_volume
]
&&
!
vd
->
histogram
[
0x8000
-
max_volume
])
max_volume
--
;
av_log
(
ctx
,
AV_LOG_INFO
,
"max_volume: %.1f dB
\n
"
,
-
logdb
(
max_volume
*
max_volume
));
for
(
i
=
0
;
i
<
0x10000
;
i
++
)
histdb
[(
int
)
logdb
((
i
-
0x8000
)
*
(
i
-
0x8000
))]
+=
vd
->
histogram
[
i
];
for
(
i
=
0
;
i
<=
MAX_DB
&&
!
histdb
[
i
];
i
++
);
for
(;
i
<=
MAX_DB
&&
sum
<
nb_samples
/
1000
;
i
++
)
{
av_log
(
ctx
,
AV_LOG_INFO
,
"histogram_%ddb: %"
PRId64
"
\n
"
,
i
,
histdb
[
i
]);
sum
+=
histdb
[
i
];
}
}
static
int
request_frame
(
AVFilterLink
*
outlink
)
{
AVFilterContext
*
ctx
=
outlink
->
src
;
int
ret
=
ff_request_frame
(
ctx
->
inputs
[
0
]);
if
(
ret
==
AVERROR_EOF
)
print_stats
(
ctx
);
return
ret
;
}
AVFilter
avfilter_af_volumedetect
=
{
.
name
=
"volumedetect"
,
.
description
=
NULL_IF_CONFIG_SMALL
(
"Detect audio volume."
),
.
priv_size
=
sizeof
(
VolDetectContext
),
.
query_formats
=
query_formats
,
.
inputs
=
(
const
AVFilterPad
[])
{
{
.
name
=
"default"
,
.
type
=
AVMEDIA_TYPE_AUDIO
,
.
get_audio_buffer
=
ff_null_get_audio_buffer
,
.
filter_samples
=
filter_samples
,
.
min_perms
=
AV_PERM_READ
,
},
{
.
name
=
NULL
}
},
.
outputs
=
(
const
AVFilterPad
[])
{
{
.
name
=
"default"
,
.
type
=
AVMEDIA_TYPE_AUDIO
,
.
request_frame
=
request_frame
,
},
{
.
name
=
NULL
}
},
};
libavfilter/allfilters.c
View file @
5980e57c
...
@@ -57,6 +57,7 @@ void avfilter_register_all(void)
...
@@ -57,6 +57,7 @@ void avfilter_register_all(void)
REGISTER_FILTER
(
PAN
,
pan
,
af
);
REGISTER_FILTER
(
PAN
,
pan
,
af
);
REGISTER_FILTER
(
SILENCEDETECT
,
silencedetect
,
af
);
REGISTER_FILTER
(
SILENCEDETECT
,
silencedetect
,
af
);
REGISTER_FILTER
(
VOLUME
,
volume
,
af
);
REGISTER_FILTER
(
VOLUME
,
volume
,
af
);
REGISTER_FILTER
(
VOLUMEDETECT
,
volumedetect
,
af
);
REGISTER_FILTER
(
RESAMPLE
,
resample
,
af
);
REGISTER_FILTER
(
RESAMPLE
,
resample
,
af
);
REGISTER_FILTER
(
AEVALSRC
,
aevalsrc
,
asrc
);
REGISTER_FILTER
(
AEVALSRC
,
aevalsrc
,
asrc
);
...
...
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