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

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

TB

timebase of the input timestamps