<P> The header consists of many parts and may include quantization tables and 2048 bits of user data . Each frame also has two GUIDs and timestamp . The frame header is packed into big - endian dwords . Actual frame data consists of packed macroblocks using a technique almost identical to JPEG: DC prediction and variable - length codes with run length encoding for other 63 coefficients . DC coefficient is not quantized . </P> <P> The codec supports alpha channel information . </P> <P> The DNxHD codec was submitted to the SMPTE organization as the framework for the VC - 3 family of standards . It was approved as SMPTE VC - 3 after a two - year testing and validation process in 2008 and 2009: </P> <Ul> <Li> SMPTE 2019 - 1 - 2008 VC - 3 Picture Compression and Data Stream Format </Li> <Li> SMPTE 2019 - 3 - 2008 VC - 3 Type Data Stream Mapping Over SDTI </Li> <Li> SMPTE 2019 - 4 - 2009 Mapping VC - 3 Coding Units into the MXF Generic Container </Li> <Li> RP (Recommended Practices) 2019 - 2 - 2009 VC - 3 Decoder and Bitstream Conformance </Li> </Ul>

What does the v in avid stand for