Video variable frame rate indication

Overview

Containing profile atom: Track (video), movie
part-ID: 0x20202020 (universal feature)
feature-code: 'vvfp'
feature-value: Unsigned int(32) holding the value 0 if the frame rate is constant or the value 1 if the frame durations vary

Feature Values

The feature value holds one of the following two values: 0 if all video samples have the same display duration, or 1 if any video samples vary in duration.

Writer Responsibilities

A writer of the Video Variable Frame Rate Indication feature should compare the video track sample durations. If all considered durations have the same value, the value 0 indicating constant frame rate should be recorded. If any durations differ, the value 1 should be recorded for the feature. No other value should be recorded.

Feature Value Algorithm

If the Time to Sample table records a constant duration for all samples, then record 0, else record 1.

Reader Responsibilities

A reader of this feature code should only expect the values 0 or 1.