Skip to content
Projects
Groups
Snippets
Help
Loading...
Help
Contribute to GitLab
Sign in / Register
Toggle navigation
F
ffmpeg.wasm-core
Project
Project
Details
Activity
Cycle Analytics
Repository
Repository
Files
Commits
Branches
Tags
Contributors
Graph
Compare
Charts
Issues
0
Issues
0
List
Board
Labels
Milestones
Merge Requests
0
Merge Requests
0
CI / CD
CI / CD
Pipelines
Jobs
Schedules
Charts
Wiki
Wiki
Snippets
Snippets
Members
Members
Collapse sidebar
Close sidebar
Activity
Graph
Charts
Create a new issue
Jobs
Commits
Issue Boards
Open sidebar
Linshizhi
ffmpeg.wasm-core
Commits
64e174e8
Commit
64e174e8
authored
Dec 08, 2012
by
Stefano Sabatini
Browse files
Options
Browse Files
Download
Email Patches
Plain Diff
doc/filters: move volumedetect documentation below volume
parent
10db70d5
Hide whitespace changes
Inline
Side-by-side
Showing
1 changed file
with
40 additions
and
40 deletions
+40
-40
filters.texi
doc/filters.texi
+40
-40
No files found.
doc/filters.texi
View file @
64e174e8
...
@@ -829,46 +829,6 @@ out
...
@@ -829,46 +829,6 @@ out
Convert the audio sample format, sample rate and channel layout. This filter is
Convert the audio sample format, sample rate and channel layout. This filter is
not meant to be used directly.
not meant to be used directly.
@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 volume
@section volume
Adjust the input audio volume.
Adjust the input audio volume.
...
@@ -934,6 +894,46 @@ volume=volume=6dB:precision=fixed
...
@@ -934,6 +894,46 @@ volume=volume=6dB:precision=fixed
@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.
@c man end AUDIO FILTERS
@c man end AUDIO FILTERS
@chapter Audio Sources
@chapter Audio Sources
...
...
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment