Summary

For distribution of video content encoded in the multiple types of compression methods, bitstream domain splicing between these heterogeneous bitstreams are necessary to avoid picture quality degradation and latency caused by transcoding.

Recommendation ITU-T J.286 defines a messaging format and constraints on bitstreams to achieve seamless splicing of heterogeneous bitstreams that conform to Recommendation ITU-T H.262 | ISO/IEC 13818-2 (also known as "MPEG-2 video") or Recommendation ITU-T H.264 | ISO/IEC14496-10 (also known as "MPEG-4 AVC"). The messaging format is defined as an extension of Recommendation ITU-T J.181, which is intended to enable the splicing device with relevant information of the bitstreams to be spliced. If the splicing device is aware of the video coding types of the subsequent bitstream in advance of the splicing event, it would be able to take more appropriate action for splicing of the different types of bitstreams. This Recommendation thus provides a mechanism to notify the type of the bitstream to be switched over. In addition, constraints on the bitstreams are also defined based on Recommendation ITU-T J.189 to facilitate seamless playback between MPEG-2 video and ITU-T H.264 by the decoder that satisfies requirements for seamless splicing of heterogeneous bitstreams.

For seamless splicing, such constraints can apply at the encoder when it compresses an input video or at the splicing device by making modifications on input bitstreams. The decoder is required to be capable of seamless decoding and playback of concatenated bitstreams conforming to the constraints defined by this Recommendation. This means that a conventional dual-mode decoder requiring firmware reloading and resetting to change the mode might not be functional. How to apply the constraints at the encoder or at the splicing device, how to upgrade the existing ITU-T J.181 splicing devices to ITU-T J.286 ones, and how to develop the decoder for this system is design dependent, and outside the scope of this Recommendation.