SMPTE 356M is a SMPTE specification for a professional video format, it is composed of MPEG-2 video composed of only I-frames and using 4:2:2 chroma subsampling. 8 channel AES3 audio streams are also included. These AES3 audio usually contain 24 bit PCM audio samples. SMPTE 356M requires up to of bandwidth.
This format is described in the document SMPTE 356M-2001, "Type D-10 Stream Specifications — MPEG-2 4:2:2P @ ML for 525/60 and 625/50".
The technology specified in SMPTE 356M is also known as D10 or D-10 and also called IMX by Sony.