HDV is a low-cost prosumer format that allows you to record HD video onto standard DV videocassettes. This is achieved through the use of interframe compression, where a given frame in the video stream can be composed of information from adjacent frames. Interframe compression is more efficient than frame-based schemes (such as DV25), allowing high-bandwidth HD images to be contained on media designed for standard definition (SD). However, HDV is more difficult to edit since frames are not independent of one another. Avid provides a solution that allows you to edit natively with HDV-compressed video without requiring a transcode to frame-based media.

HDV utilizes MPEG-2 video encoding and MPEG-1 audio encoding. 1080i records at about 25Mbps and 720p records at about 19Mbps. Sony provides HDV cameras that record at 1080i/59.94 and 1080i/50.

In the 1080i formats, the data rate of the video is reduced before compression by horizontally resizing the video display (raster) from 1920 x 1080 pixels to 1440 x 1080 pixels. In contrast, 720p HDV uses the standard raster size of 1280 x 720. A new resolution, Avid DNxHD-TR (for Thin Raster), improves the performance of 1080i HDV editing. This resolution matches the 1080i HDV raster size, reducing artifacts that would come from repeated compressions when rendering effects and graphics.

Contact your CEV representative for more information.

[October 12, 2005]