numframes

Numframes is a term used in video, animation, and image sequence contexts to denote the total number of individual frames in a sequence. It is typically an integer that defines the length of the sequence and is used by editors, renderers, and analyzers to determine how many images must be processed or displayed.

Relation to duration and frame rate: If the sequence has a constant frame rate f (frames per second) and a duration of T seconds, the expected frame count is f × T. In practice the reported value is an integer derived from this product and may be affected by rounding, frame drops, or padding at the ends.

Fixed vs variable frame rate: With a fixed-frame-rate source, numframes is straightforward. For variable frame rate content, the total still equals the sum of all frames across the timeline, but the timing of each frame varies and may complicate precise time mapping.

Formats and APIs: Some containers and tools expose a total frame count (for example nb_frames or frame_count). Others omit it until decoding completes, requiring counting frames during processing. Other scenarios estimate frames from timecodes or metadata.

Notes and pitfalls: Interlacing, field versus frame counting, and dropped or duplicated frames can cause discrepancies between different reports of numframes. When designing workflows, consider whether you need a hard total, a time-based duration, or a per-frame index, and be mindful of how different formats report frame counts.