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https://github.com/ferreum/mpv-skipsilence

Increase playback speed during silence - a revolution in attention-deficit induction technology.
https://github.com/ferreum/mpv-skipsilence

mpv mpv-scripts

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Increase playback speed during silence - a revolution in attention-deficit induction technology.

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# mpv-skipsilence



Increase playback speed during silence - a revolution in attention-deficit

induction technology.



Main repository: https://codeberg.org/ferreum/mpv-skipsilence/



Based on the script https://gist.github.com/bitingsock/e8a56446ad9c1ed92d872aeb38edf124



This is inspired by the NewPipe app's built-in "Fast-forward during silence"

feature.



> Note: In mpv version 0.36 and below, the `scaletempo2` filter (default since

> mpv version 0.34) caused audio-video de-synchronization when changing speed

> a lot. This has been fixed in mpv 0.37. See [mpv issue

> #12028](https://github.com/mpv-player/mpv/issues/12028). Small, frequent

> speed changes instead of large steps may help to reduce this problem. The

> scaletempo and rubberband filters didn't have this problem, but have

> different audio quality characteristics.



## Features:



- Parameterized speedup ramp, allowing profiles for different kinds of

  media (`ramp_*`, `speed_*`, `startdelay` options).

- Noise reduction of the detected signal. This allows to speed up

  pauses in speech despite background noise. The output audio is

  unaffected by default (`arnndn_*` options).

- Saved time estimation.

- Integration with osd-msg, auto profiles, etc. (with user-data, mpv 0.36 and

  above only).

- Experimental: Lookahead for dynamic slowdown and faster reaction time

  (`lookahead`, `slowdown_ramp_*`, `margin_*` options).

- Workaround for scaletempo2 audio-video desynchronization in mpv 0.36 and

  below (`resync_threshold_droppedframes` option).

- Workaround for clicks during speed changes with scaletempo2 in mpv 0.36 and

  below (`alt_normal_speed` option).



### Silence detection visualized



The following graph shows an example silence detection and resulting playback

speed, annotated with options that impact speed changes.



![silence detection visualization](./images/detection.svg)



If the experimental `lookahead` option is set to a positive value, the effect

of some options changes:



1) Without lookahead, `Silence Start` is delayed by

`threshold_duration`. If lookahead is active, it reduces this delay by up to

that configured lookahead duration.



2) `minduration` is only supported with lookahead.



3) `startdelay` is ignored if lookahead is enabled and

`margin_start` is used instead.



4) The box marked `if lookahead` only applies if lookahead is

active. Otherwise, the speed is reverted in a single step exactly at the time

of `Silence End` detection.



## Default bindings



- F2 - toggle

- F3 - threshold-down

- F4 - threshold-up



## Documentation



For detailed usage check the comments at the top of the [script](skipsilence.lua).



## Recommendations



### Temporarily disable display sync



When using `video-sync=display-*`, speed changes tend to cause increased video

lag. Because display sync is less useful while speed keeps changing, it's

recommended to use `video-sync=audio` (the default) while this script is

active. This results in smoother video playback during speed transitions.



The following profile can be used to automatically switch to `video-sync=audio`

when skipsilence is enabled and restore it when disabled (requires mpv 0.36 or

above for user-data):



    [auto-skipsilence-videosync]

    profile-cond=get("user-data/skipsilence/enabled")

    profile-restore=copy-equal

    video-sync=audio



### Fix clicking sounds/gaps when switching to and from 1x speed



In the default configuration, mpv automatically inserts scaletempo2 filter when

changing speed and removes it when returning to 1x playback speed. This often

causes clicks in audio playback. To prevent this, add `scaletempo2` to the `af`

filter list explicitly:



    af-add=scaletempo2



In mpv 0.36 and below, the scaletempo2 filter itself additionally caused

similar artifacts when switching to and from 1x speed. This has been fixed in

mpv 0.37. The `alt_normal_speed` option of this script is a workaround for

older versions.



### Fix silence at high playback speed



By default, scaletempo2 produces silence above 8x playback speed (4x in mpv

0.36 and below). To lift this limit, set the `max-speed` parameter in the

filter definition (see above) like this:



    af-add=scaletempo2=max-speed=16.0



### Maximize skipping speed



Because of the asynchronous nature of scripts, there is latency between silence

detection and speed changes. The higher the playback speed, the more noticeably

playback will overshoot before normal speed is restored. What speeds are

acceptable depends on the performance/latency of the system.



To maximize skipping speed, start with the extreme profile (see

[Profiles](#profiles) below). Then adjust `ramp_constant`, `ramp_factor`,

`max_speed` options as needed.



- If overshooting happens all the time, even for very short pauses, reduce

  `ramp_constant`.

- If it happens after the speed ramped up more, focus on `ramp_factor`.

- For the occasional long stretch of silence this may be less of a problem, but

  can be improved by reducing `max_speed` at a cost of slower skipping.

- Notice that extreme values of `ramp_exponent` tend to be less useful. It's

  recommended to keep the `ramp_exponent` around 0.9 for aggressive profiles.



#### Lookahead



The experimental lookahead option makes much higher maximum speed practical by

gradually slowing down before the end of silence is reached. See the

`lookahead`, `slowdown_ramp_*` and `margin_*` options. To maximize skipping

speed, use a slowdown ramp that is as steep as possible without overshooting on

slowdown. `margin_end` can help, but is usually not required.



### Profiles



Mpv's profiles can be used to switch between different presets. Create profiles

in `mpv.conf` and apply them with the `apply-profile` command.



    [skipsilence-default]

    script-opts-append=skipsilence-ramp_constant=1.25

    script-opts-append=skipsilence-ramp_factor=2.5

    script-opts-append=skipsilence-ramp_exponent=1

    script-opts-append=skipsilence-speed_max=4

    script-opts-append=skipsilence-speed_updateinterval=0.05

    script-opts-append=skipsilence-startdelay=0.05



Bind it to a key in `input.conf`:



    F5 script-message-to skipsilence enable no-osd; apply-profile skipsilence-default; show-text "skipsilence profile: default"



#### Examples



    # very smooth speed increase, up to 3x

    [skipsilence-smooth]

    script-opts-append=skipsilence-ramp_constant=1

    script-opts-append=skipsilence-ramp_factor=0.4

    script-opts-append=skipsilence-ramp_exponent=1.45

    script-opts-append=skipsilence-speed_max=3

    script-opts-append=skipsilence-speed_updateinterval=0.05

    script-opts-append=skipsilence-startdelay=0

    script-opts-append=skipsilence-threshold_duration=0.25



    # very aggressive skipping, can make it hard to listen

    [skipsilence-extreme]

    script-opts-append=skipsilence-ramp_constant=2.5

    script-opts-append=skipsilence-ramp_factor=10

    script-opts-append=skipsilence-ramp_exponent=0.9

    script-opts-append=skipsilence-speed_max=6

    script-opts-append=skipsilence-speed_updateinterval=0.05

    script-opts-append=skipsilence-startdelay=0

    script-opts-append=skipsilence-threshold_duration=0.05



    # long wait (1s) before speeding up quickly

    [skipsilence-patient]

    script-opts-append=skipsilence-ramp_constant=1.25

    script-opts-append=skipsilence-ramp_factor=3

    script-opts-append=skipsilence-ramp_exponent=0.9

    script-opts-append=skipsilence-speed_max=4

    script-opts-append=skipsilence-speed_updateinterval=0.05

    script-opts-append=skipsilence-startdelay=0

    script-opts-append=skipsilence-threshold_duration=1