[FFmpeg-devel] [PATCH] doc/filters: move volume documentation above volumedetect

Clément Bœsch ubitux at gmail.com
Sat Dec 8 15:21:32 CET 2012


On Sat, Dec 08, 2012 at 12:10:16PM +0100, Stefano Sabatini wrote:
> ---
>  doc/filters.texi |   80 +++++++++++++++++++++++++++---------------------------
>  1 file changed, 40 insertions(+), 40 deletions(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index a2d4a19..57629f9 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -829,46 +829,6 @@ out
>  Convert the audio sample format, sample rate and channel layout. This filter is
>  not meant to be used directly.
>  
> - at 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:
> - at 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
> - at end example
> -
> -It means that:
> - at itemize
> - at item
> -The mean square energy is approximately -27 dB, or 10^-2.7.
> - at item
> -The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
> - at item
> -There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
> - at 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
>  
>  Adjust the input audio volume.
> @@ -934,6 +894,46 @@ volume=volume=6dB:precision=fixed
>  @end example
>  @end itemize
>  
> + at 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:
> + at 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
> + at end example
> +
> +It means that:
> + at itemize
> + at item
> +The mean square energy is approximately -27 dB, or 10^-2.7.
> + at item
> +The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
> + at item
> +There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
> + at 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
>  
>  @chapter Audio Sources

OK

-- 
Clément B.
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