transport stream. In order to ensure that the stream maintains a constant bitrate, a multiplexer may need to insert some additional packets. The PID 0x1FFF is reserved for this purpose. The payload of null packets is all zeroes, and the receiver is expected to ignore its contents. Use in digital video cameras Transport Stream was originally designed for broadcast. Later it was adapted for use with digital video cameras, recorders and players by adding a 4-byte timecode (TC) field to the standard 188-byte packets, resulting in a 192-byte packet. This is what is informally called M2TS stream. The Blu-ray Disc Association calls it "BDAV MPEG-2 transport stream". JVC called it TOD when used in HDD-based camcorders like GZ-HD7. The timecode allows quick access to any part of the stream either from a media player, or from a non-linear video editing system. It is also used to synchronize video streams from several cameras in a multiple-camera setup. Use in Blu-ray Blu-ray Disc video titles authored with menu support are in the Blu-ray Disc Movie (BDMV) format and contain audio, video, and other streams in a BDAV container, which is based on the MPEG-2 transport stream format. Blu-ray Disc video uses these modified MPEG-2 transport streams, compared to DVD's program streams that don't have the extra transport overhead. There is also the BDAV (Blu-ray Disc Audio/Visual) format, the consumer-oriented alternative to the BDMV format used for movie releases. The BDAV format is used on Blu-ray Disc recordable for audio/video recording. Blu-ray Disc employs the MPEG-2 transport stream recording method. This enables transport streams of a BDAV converted digital broadcast to be recorded as they are with minimal alteration of the packets. It also enables simple stream cut style editing of a BDAV converted digital broadcast that is recorded as is and where the data can be edited just by discarding unwanted packets from the stream. Although it is quite natural, a function for high-speed and easy-to-use retrieval is built in. See also MPEG media transport (MMT) Real-time Transport Protocol (RTP) Unidirectional Lightweight Encapsulation (ULE) Notes References External links ITU-T H.222.0 | ISO/IEC 13818-1 Systems Spec Documents Latest free copy of the spec, August 2018 MPEG-4 Systems FAQ TSDuck – Free open-source tool to manipulate MPEG transport streams. ATSC Digital container formats MPEG-2 ITU-T recommendations