Some say that if you have a computer that can edit DV, you have a computer that can edit HDV. HDV in 1080i format is the same bitrate (25Mbps) as DV is. However, depending on the system, you may experience choking on the system, depending on whether you're editing Transport Streams or with an intermediary codec such as the Cineform Connect HD codec

If you have a processor of at least 2.6 Ghz or faster, you'll be plenty fast to edit HDV, particularly if you use an intermediary codec.

An intermediary codec is like a translator, or "in-between" codec, that assists the editing software. Connect HD (for Sony Vegas) Aspect HD (for Adobe Premiere) and Lumiere (for Final Cut Pro) are all intermediary codecs. You capture in either native MPEG from the HDV camera, and the video is converted to the intermediary either in real time after capture, or during capture. This assists in the editing process, as native MPEG transport streams are very heavy on the processor, and may be difficult to edit. Further, you don't want to be editing the raw MPEG transport stream because you'll endure a potentially significant loss of quality without the intermediary.

When you render to print to tape, if you wish to print to your HDV camera, the intermediary will re-convert the intermediate stream to the MPEG format once again, providing you with a great image.

While DV or DVC Pro are very easy for the computer to edit, HDV in its native form is extremely difficult for any computer to handle. Even a simple cut in a native HDV editing system will cause some kind of change to the video.
This means that new video has to be generated which taxes your computer's CPU.

More complicated things such as color correction, titles, and resizing video frames will cause all of the affected video to be re-generated. Therefore, in many situations, native HDV editing offers little or no advantage because so much new video needs to be created

To avoid these problems, the best thing to do is convert HDV into an I-Frame based video codec. There are several good choices for this, such as DVC Pro HD, the Apple Intermediate Codec, and Uncompressed 8 bit and 10 bit. Once the video is converted to one of these formats, editing becomes a lot easier. The computer doesn't have to work so hard decompressing the HDV video.

I-frame based codecs don't require re-rendering when a cut edit is made.

I-frame rendering is a lot less CPU intensive and many effects can be done in real-time and displayed on an external monitor. This means more streams of video can be combined on the screen in real-time.

The downside of converting video from HDV to another format is that it requires more hard drive space and it takes time to do the conversion.

First the HDV video has to be captured to the computer and then converted to another codec. This conversion process can be very fast for codecs such as the Apple Intermediate Codec or Uncompressed HD, but DVC Pro HD will take much longer because the video must be re-sized to fit. While the HDV video file requires 14 gigabytes per hour of video, DVC Pro HD requires 4 times as much space for 1080i.

Uncompressed HD requires as much as 500 gigabytes per hour. However, the cost of the extra hard drive space may be trivial compared to the amount of time and money you save in editing and post production.

Last update: 02:47 PM Monday, August 14, 2006