Module sync 

The player’s timing rules, free of FFmpeg so they can be tested: the wall clock, the audio clock, the queue of decoded frames waiting to be shown, the arithmetic of timestamps and seeks, and the bookkeeping of sound stretched to another speed.

Structs

AudioClock

Where the sound is: the media time of the first sample of the chunk the output last took, when it took it, and how much media time that chunk covers (at speed rate, each second of samples covers rate seconds of the clip, whose pitch stays put). Between takes the clock runs on from the chunk’s start, but never past its end, so a starved output stops the clock.

FrameQueue

Decoded frames waiting for their time, oldest first.

TempoTimeline

The media time of sound coming out of a tempo filter, which holds some back: every sample out covers rate samples in, counted from the time of the first sample in, so the timestamps on what goes in don’t apply to what comes out of the same call.

WallClock

A media clock running off the wall clock: pts at wall time since, advancing at rate while running and frozen while paused. Times are seconds; the wall time is passed in, so the clock is plain arithmetic.

Constants

MAX_QUEUED_FRAMES

QUEUE_BYTES

Functions

before_target

Whether a frame at pts is still before a seek’s target and should be decoded but not shown: the next frame (one frame time later) would already be showing at target. The decoder starts at the keyframe before the target and works forward to the frame on screen at it.

display_width

The shown width of a picture w pixels wide with sample aspect ratio sar (anamorphic DVD video has non-square pixels).

fit

The size to scale a w × h picture to so its long side is at most max_side, never enlarging.

needs_tempo

Whether sound at rate needs stretching. At normal speed (to within the player’s own tolerance) it skips the filter altogether.

queue_cap

How many decoded frames of bytes each to keep ready: up to MAX_QUEUED_FRAMES, within QUEUE_BYTES, and never fewer than two.

secs

Seconds of a timestamp in tb, measured from the stream’s start (also in tb; files that don’t start at zero, such as MPEG-TS captures, show from 0). None for a missing timestamp.

seek_ts

The container timestamp (AV_TIME_BASE units, as av_seek_frame takes with stream -1) of t seconds after the file’s start.

step_back

The time to seek to for a step of frames back from shown.

tempo_chain

The atempo speeds to chain for rate (clamped to the player’s 0.1 to 16): one filter, with halving filters ahead of it below 0.5, as FFmpeg’s documentation describes. Their product is rate.

thumbnail_time

Where Eagle’s thumbnailer takes a video’s picture: ten seconds in, or a third of the way through a clip shorter than thirty seconds.

turns_from_degrees

Clockwise quarter turns (0 to 3) for a display matrix rotation, which FFmpeg gives in degrees anticlockwise.