SMPTE 259M is a standard

Standardization

Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....

 published by SMPTE which "... describes a 10-bit serial digital interface operating at 143/270/360 Mb/s."

The goal of SMPTE 259M is to define a Serial Digital Interface

Serial Digital Interface

Serial digital interface is a family of video interfaces standardized by SMPTE. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video...

 (based on a coax cable), called SDI

Serial Digital Interface

Serial digital interface is a family of video interfaces standardized by SMPTE. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video...

 or SD-SDI.

There are 4 bitrates defined, which are normally used to transfer the following standard video formats:

Variant	Bitrate	Display Aspect Ratio Aspect ratio (image) The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...	Total Lines (per Frame)	Active Pixels	Active Lines	Framerate
SMPTE 259M-A	143 Mbit/s	4:3	525	768	486	59.94i
SMPTE 259M-B	177 Mbit/s	4:3	625	948	576	50i
SMPTE 259M-C	270 Mbit/s	4:3 or 16:9	525	720	486	59.94i
SMPTE 259M-C	270 Mbit/s	4:3 or 16:9	625	720	576	50i
SMPTE 259M-D	360 Mbit/s	16:9	525	960	486	59.94i