Previewing HDV in Real Time

By Shawn Amaro

Many video producers are switching from SD to HDV and are finding out that their current systems are unable to preview out to an external monitor. There are several hardware solutions on the market that can make an HDV workflow run as smooth as your existing SD system. This article explores the various options for creating a real-time preview out on either a Mac or PC with either a PCI Express or external solution.

Real-time previewing requires hardware due to HDV's MPEG-2 video compression. This involves recording full frames (I frames) and partial frames. The process of compression saves on file size and allows the camcorders to use the same tape transport as DV. These full and partial frames are known as intraframe and interframe (temporal) frames. Since DV records each frame of a video as an independent object, the footage can be spliced at any frame without complications or additional rendering. Editing the native MPEG-2 video format of HDV requires a decoding and reconforming of the entire HDV frame group for each cut. This constant decompressing and recompressing, plus the need for physical connectors, makes a hardware component necessary for previewing out.

Choosing the right connection between your computer and preview monitor is important. You can monitor HDV on a computer monitor that has at least 1900 x 1200 resolution, or an external HD television monitor as long as the aspect ratio in HDV is 16:9 with resolutions of 720p and 1080i. Viewing HDV in your NLE application is reasonably accurate but is not recommended for professional color correction due to its limited color gamut.

Panasonic BT-LH2600W

The Panasonic BT-LH2600W 26" Widescreen HD/SD LCD Video Monitor offers professional-grade color correction in a 26" true 16:9 widescreen HD screen designed for broadcast and studio applications. By using Panasonic's Pixel to Pixel mode, the user sees their video in its native resolution. You can choose to display audio information over the image for increased efficiency when monitoring video footage. The monitor displays the same EBU-based colors as CRT monitors by using the Color-Space Conversion process to compensate for the differences in an LCD monitor's chromatic range.

Most HD monitors will have at least one or all of the following options: HDMI, Component or HD/SDI. HDMI (High-Definition Multimedia Interface) is a single cable that sends both audio and video digitally to your previewing set. Connecting an HD television by component involves three separate RCA cables for splitting the video into red, blue, and green analog signals and then a separate set of cables for audio. The pro level connection is an HD/SDI connection which sends both audio and video through one BNC cable.

Blackmagic's Intensity and Intensity Pro

The popular choice for previewing HDV footage is HDMI, because of its clarity, and for sending signals digitally uncompressed. The PCI-Express Blackmagic Intensity and Intensity Pro cards are excellent and economical choices for HDMI previewing, supporting 4:2:2 video while working in Final Cut Pro or Adobe Premiere Pro. The Intensity Pro also includes analog video output in NTSC or PAL via component, composite or S-Video. The Intensity is fully compatible with Mac OS X and Windows XP, making your operating platform a non-issue. Other Blackmagic products, such as the Decklink and Multibridge series, can provide preview out of HDV as well as other formats and levels of connectivity.

Aja's Kona 3 for Mac and Xena LHe for Windows

The Aja Kona and Xena series of HD cards will also provide real-time video output for HDV. Kona series is used by customers who want HD/SDI or analog inputs/outputs, using hardware instead of software to assist in mixing true HD footage with HDV footage. Working in HD can be easier on the CPU and rendering, but the files sizes are larger, requiring your editing system to have hard drives with a faster transfer rate. The Kona line of products works only with Final Cut Pro on a Mac OSX operating system. The Xena card works as a plugin for Adobe Premiere, Adobe After Effects, Photoshop, Autodesk Combustion, and Eyeon Fusion 5. Also, XENA 3rd-party support is available for Avid Liquid Chrome Xe (LHe only—LH not supported), Sony Vegas and Sonic CineVision PSE.

Avid Liquid Pro 7

Avid Liquid Pro 7 for Windows provides a whole host of connectivity options at a low cost. Liquid Pro allows for real-time effects in multiple streams of HDV, video monitoring full-screen, or down-converted to an SD monitor in real time and output in HD/SD. Liquid lets you edit in HDV as well as many MPEG formats, including DivX. NAB 2007 saw the introduction of support for the Aja Xena LHe and progressive HDV video formats from the JVC GY-HD100 and 200 series cameras.

Matrox MXO makes HDV connectivity for MacBook users easy

The Matrox MXO is an external HD and SD video output device for use with Final Cut Pro on the Mac. Portability is a major benefit for this hot-swappable device, allowing it to work on a desktop or laptop. The MXO connects to a DVI port, sending genlockable HD/SD SDI, HD/SD analog component, Y/C, and composite outputs with up to 8 channels SDI embedded audio output and stereo audio monitoring to your video monitor.

Grass Valley offers tons of features, including realtime HDV previewing.

The Grass Valley NX with Edius Pro supports HDV I/O and native HDV editing. The card includes analog and digital inputs/outputs for DV, S-Video, composite video, and unbalanced audio. A user may obtain an optional video I/O module available for XDCAM, DVCPRO 50, DVCPRO HD, P2 and VariCam. The card can be a real time saver, due to the hardware-based SD MPEG-2 and MPEG-4 timeline export.

The switch to HDV may be cumbersome at times, but the rewards are worth it. Once you know which editing software and type of connectivity is right for you, choosing your preview card will be easy. Now start bringing your footage to its full potential.