AssumeSampleRate

Changes the sample rate of the current clip without changing the number of samples.

• This changes the sample rate, pitch, playback speed and running time of the audio.

• It will also affect synchronization with the video.

Syntax and Parameters

AssumeSampleRate (clip, int samplerate)

clip

Source clip; all color formats and audio sample types supported.

samplerate

New sample rate.

Examples

Fix an audio sync problem:

AviSource("video_audio.avi")
# Let's say that this clip loses audio sync:
# by the end, the audio is behind by 200 milliseconds.

Ar  = AudioRate()     # original audio sample rate
dur = AudioDuration() # total duration in seconds
adj = -0.200          # correction needed (decrease audio duration by 200 msec)

# Adjust audio duration:
AssumeSampleRate(Round(dur / (dur+adj) * Ar))

# Video and audio are now in sync.

# (optional) restore original sample rate.
#ResampleAudio(Ar)

Play video and audio at half speed:

AviSource("video_audio.avi")

# Play video at half speed: audio will be out of sync
AssumeFPS(FrameRate/2)

# Play audio at half speed: (pitch will be lowered by an octave)
AssumeSampleRate(AudioRate/2)

# Video and audio are now in sync.
# Equivalent to calling AssumeFPS(..., sync_audio=true) (see below)

See also

AssumeFPS: sync_audio

If true, the audio sample rate is changed by the same amount; the pitch of the resulting audio is shifted.

If false (the default), the audio is unchanged; this means the audio will lose synchronization over time.

Changelog

Version	Changes
AviSynth 2.0.7	First added

$Date: 2022/03/17 15:28:44 $