CNET's quick guide to HD camcorders
By Lori Grunin, CNET.comFeb 05, 2007
HD recording formats: 720p or 1080i
So what's the difference between 720p and 10780i? The short answer is that they both look great, and most people have a hard time telling the difference. Here's the medium-size answer: The numbers 720 and 1080 refer to horizontal pixel counts, while the letters p and i refer to the picture-scanning method--either progressive or interlaced. (David Katzmaier, CNET.com)| 720p | 1080i | ||
| Example products |  Sanyo Xacti VPC-HD1 |
 JVC GY-HD110U  JVC GY-HD100U  JVC GR-HD1 |
Currently used by pro products costing upwards of US$16,000. |
| Recording format | MPEG-4 | JVC ProHD HDV variation limited to 720p capture |
Sony XDCAM HD (a.k.a. MPEG HD) |
| Supported media types | Flash, hard disk | Tape, hard disk | Proprietary disc format |
| Format details | MPEG-2 with intraframe-only compression (MP@H-14) Max bit rate: 19.7Mbps Capture resolution: 1,280x760 Encoding resolution: 1,280x720 Color sampling: 4:2:0 Variable frame rate: yes |
MPEG-2 with intraframe-only compression (MP@H-14) Max bit rate: 19.7Mbps Capture resolution: 1280x720 Encoding resolution: 1280x720 Color sampling: 4:2:0 Variable frame rate: yes |
MPEG-2 MP@HL compression, a high-bit rate inter- and intraframe compressor Max bit rate: 35Mbps Capture resolution: 1,920x1,080 Encoding resolution: 1,440x1,080 Color sampling: 4:2:0 Variable frame rate: yes |
| Hardware issues | Quality may vary widely across different products because unlike most other formats, MPEG-4 doesn't mandate predetermined bit rate levels; for instance, the Sanyo camcorder operates at 9Mbps, far below the 19.7Mbps maximum. | Tapes recorded in ProHD format can be played only by JVC camcorders and JVC professional decks. | Did we mention the proprietary disc format? Designed for closed-system work flows. |
| Video--editing issues | At low bit rates, the highly compressed originals won't stand up well to subsequent editing and recompression. | None | Supported only by high-end video-editing software. |
