[FFmpeg-user] silenceremove use

[Paul B Mahol]

On 2/21/20, To ny <tonynederpel at hotmail.com> wrote:
> Made a wave file of the first (softest) thump with the -accurate_seek, -t
> and -ss
> and one of the "relative" silence parts and as Ted suggested checked with
> showvolume:
>
> ffplay -f lavfi -i “amovie=sample.wav,showvolume"
> This way it's especially insightful to see the volume level of very short
> sounds.
>
> thump -37.8dB  silence -48dB
>
> Used this one in ffmpeg now:
> silenceremove=start_periods=1:start_duration=0:start_threshold=-37dB:detection=peak:window=0
>
> the step from -38dB to -37dB already nibbles off the leading silence and
> 36ms of the first thump.
> Going up to a certain threshold removs the first thump but silences of
> seconds are still left in.
>
> As it seems with the silenceremove i can't differentiate between the
> relative silence and the louder
> thump.
>
> I discovered the "truncate silence" in audacity now. It gets it done and you
> can just type in
> how long you want to leave silence in between sounds and leaves everything
> above threshold
> alone.
>
> Thanks anyway to Ted and Paul.

You still have not learned anything about using ffmpeg and filter. Not
setting stop periods to -1
will remove silence only from start.

Good luck with audacity - it is big mess.

> ________________________________
> Van: ffmpeg-user <ffmpeg-user-bounces at ffmpeg.org> namens Ted Park
> <kumowoon1025 at gmail.com>
> Verzonden: vrijdag 21 februari 2020 04:53
> Aan: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
> Onderwerp: Re: [FFmpeg-user] silenceremove use
>
>> Ideally, it would be, if the thumps and voice would have some space
>> between them during playback (of the output file), like three seconds
>> apart and little bit of silence at the beginning. At the end silence isn't
>> necessary.
>>
>> Ffplay i don't have compiled but using the silenceremove arguments with
>> ffmpeg removes everything up until right before the two thumps with
>> threshold set at -38dB. The first thump is removed unfortunately. The
>> silence between the two thumps and my voice unfortunately isn't removed.
>>
>> At -37dB only my voice is left and none of the thumps are unfortunately
>> left in.
>
> Hi,
>
> Oh, sorry I misunderstood, I thought you wanted all noise cut out. I don’t
> know if this will work better since you want to include signals that are not
> much stronger than the background noise level, but have you maybe tried
> filters that reduce noise, like maybe anlmdn, rather than one that trims
> time-wise? For keeping pauses between, I think passing in the number of
> seconds for start_silence will do that for silenceremove, and you can trim
> the beginning if needed. If you want silence rather than the existing
> background noise, you could use silencedetect and use the metadata to
> generate and insert silence between sounds.
>
> Regards,
> Ted Park
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".