HDV vs AVCHD
HDV (High-Definition Video) is one of the early formats for recording HD quality videos as most companies strive to keep up with the rapid adoption of HD TV sets and players. It is basically a tape based format that uses differently sized cassettes in storing the video. A much newer format called AVCHD (Advanced Video Coding High Definition) brought tapeless designs in the forefront due to its cheap price and convenient design. The removal of the tape in favor of smaller media like SD cards and hard drives means that most AVCHD camcorders tend to be much smaller than their HDV counterparts.
The HDV format uses the older MPEG-2/H.262 specification in encoding the video while the AVCHD uses the newer MPEG-4/H.264 specification. The better encoding algorithms used by H.264 should result in videos with much better quality compared to HDV. Actually, AVCHD often produces video that is substandard compared to HDV. This is because AVCHD camcorders need to compress the video too much in order to match the write speeds of the storage media. Whereas HDV is fixed at 25mbps, AVCHD camcorders often have a bitrate of 17mbps, 13mbps or even lower; especially with low class SD memory cards.
One of the conveniences that you get when using an AVCHD camcorder is the ability to easily retrieve your videos and save it on your computer. Most of them provide a USB interface where you can pull individual video files. You can also simply remove the SD card, for those that use it, and stick it to a card reader. With an HDV camcorder, you need to playback the contents of the cassette and capture it using a video capture card and related software, like Windows Movie Maker. You can also automatically burn the AVCHD files and burn them directly into the Blu-ray format without any need for conversion, simplifying further the task of sharing videos. Since the HDV format is not compatible with Blu-ray, you need to process the video first, which can take a long time.
Summary:
1. HDV is largely a tape based format while AVCHD is a tapeless format
2. HDV camcorders are usually bigger than AVCHD camcorders
3. HDV uses MPEG-2/H.262 while AVCHD uses MPEG-4/H.264
4. HDV records at much higher bitrates compared to AVCHD
5. It is much easier to retrieve videos from an AVCHD camcorder than from an HDV
6. AVCHD has the ability to burn direct to Blu-ray while HDV does not