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Serial Data Transport Interface
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<p>Serial Data Transport Interface is a way of transmitting data packets over a <a href="/facts/Serial_digital_interface/T9VlXM56">serial digital interface</a> (SDI) datastream. This means that standard SDI infrastructure can be used. </p><p>Developed to address the needs of the growing number of compressed video standards (<a href="/facts/DV_(video_format)/WIDU6bWW">DV</a>, <a href="/facts/DVCPRO/WIDU6bWW">DVCPRO</a>, <a href="/facts/Betacam/ut9e8Lzh">BetaSX</a>, <a href="/facts/MPEG2/SpuH5FJu">MPEG2</a>) it allows lossless transfer of data to other devices which have the same codec, for example DV to DV or SX to SX. </p><p>Using a standard SDI transport, the extra data is placed within normal active video, between Start of Active Video (SAV), and End of Active Video (EAV). This gives 1440 10-bit words of data at 270 Mbit/s (1920 words in the 8-bit 360 Mbit/s standard). </p><p>If an SDTI stream is viewed using a standard SDI device, then the raw data can be seen as a small strip along the left-hand side (usually in purple). The DVCAM SDTI has video data at the top, control data in the middle (<a href="/facts/Timecode/czFCXVC7">Timecode</a>, etc.) and audio at the bottom just like it is organised on the tape. </p><p>Because SDTI is used for compressed data the area used is less than a full screen; this allows for faster than realtime transfers. </p><p>SDTI is standardized as <i><a href="/facts/SMPTE/lwCdWynu">SMPTE</a> 305M</i>. A 1.5 Gbit/s version, using the <a href="/facts/HDTV/AuE6FRFI">high definition</a> serial digital interface, is standardized as <i>SMPTE 348M</i>. </p>