Change the PTS (presentation timestamp) of the input frames.

setpts works on video frames, asetpts on audio frames.

This filter accepts the following options:

expr

The expression which is evaluated for each frame to construct its timestamp.

The expression is evaluated through the eval API and can contain the following constants:

FRAME_RATE

frame rate, only defined for constant frame-rate video

PTS

the presentation timestamp in input

N

the count of the input frame for video or the number of consumed samples, not including the current frame for audio, starting from 0.

NB_CONSUMED_SAMPLES

the number of consumed samples, not including the current frame (only audio)

NB_SAMPLES, S

the number of samples in the current frame (only audio)

SAMPLE_RATE, SR

audio sample rate

STARTPTS

the PTS of the first frame

STARTT

the time in seconds of the first frame

INTERLACED

tell if the current frame is interlaced

T

the time in seconds of the current frame

TB

the time base

POS

original position in the file of the frame, or undefined if undefined for the current frame

PREV_INPTS

previous input PTS

PREV_INT

previous input time in seconds

PREV_OUTPTS

previous output PTS

PREV_OUTT

previous output time in seconds

RTCTIME

wallclock (RTC) time in microseconds. This is deprecated, use time(0) instead.

RTCSTART

wallclock (RTC) time at the start of the movie in microseconds