packetizer

A packetizer is a software or hardware component that converts a continuous data stream into discrete packets prepared for transmission over a network. It applies protocol-specific framing, adds headers, sequence numbers, timestamps, and may segment the stream into fixed or variable-length payload units.

In data communications, packetizers ensure data conforms to network characteristics such as maximum transmission unit (MTU) and transport layer requirements (IP, UDP). They may perform segmentation, recombine segments, handle fragmentation, and contribute to quality of service by tagging packets with priority or timing information.

In multimedia and real-time communications, packetizers convert encoded media frames into transport packets. For example, an RTP packetizer may take H.264 or AAC data units (NALs or frames) and pack them into RTP payloads with appropriate markers and timestamps, enabling synchronized playback and streaming over networks such as the Internet.

Implementation considerations include latency, jitter, and overhead. The packetization interval must balance timely delivery with packing efficiency. At the receiver, packetized data must be reassembled to reconstruct the original stream, requiring correct sequencing information and clock synchronization.

Related concepts include framing, muxing/demuxing, and segmentation. Packetizers appear in network equipment, media gateways, streaming servers, and software libraries as part of the end-to-end data transport chain.