timestampValidBits

TimestampValidBits is a metadata field used in some multimedia encoding and streaming specifications to describe the precision of a sample’s timestamp. A timestamp identifies when a frame or audio sample should be presented during playback, synchronization, or processing. In certain containers or codecs, the full timestamp value may be stored with limited precision or may be partially known. TimestampValidBits communicates how many bits of the timestamp are known to be valid, with the remaining bits either unused or assumed to follow a defined rule (such as being zero).

The exact interpretation of timestampValidBits depends on the specific standard or format. In general, it allows decoders and renderers to handle timestamps even when only a portion of the value is guaranteed, enabling more efficient storage or transmission in scenarios where high precision is not strictly necessary. It often accompanies a separate timestamp field, providing a hint about the reliability or resolution of that timestamp.

Usage and presence vary across specifications. Some formats may use timestampValidBits to optimize header size, support scalable time representations, or cope with truncation in streaming pipelines. When timestampValidBits is present, implementers should consult the relevant documentation to understand how to reconstruct or validate the presentation time from the provided timestamp and its bit-width.

See also: timing, timestamps, presentation timestamp, clock reference, codecs.