This is due to USB adopting a "master-slave" topology, which means it needs the computer's CPU to coordinate data transfers. One of the worst issues with USB 2.0 is that it cannot guarantee a sustained data transfer rate. The new standard also provided for even faster 1.6Gbps and 3.2Gbps transfer rates across 100 meters of copper twisted pair wires.Īt first glance, it appears that USB 2.0 is faster than Firewire400 however speed is not the only issue when it comes to DV.
Not to be left behind by Wintel, at least on paper, Firewire800 or IEEE1394b was introduced. Then along came USB 2.0 with a "published" transfer rate of 480Mbps or 60MB per second. Transferring DV requires a transfer rate of at least 3.6MB per second, which at the time left Firewire as one of few options due to its ability to work at 400Mbps, or up to around 50MB per second. USB 1.1 could not transfer high quality DV loosely defined as 25 frames per second (fps) with each frame being 640x480 resolution, due to USB1.1's transfer limit of around 11Mbps (or around 1.5MB per second). In the past, there was a clear distinction between USB and Firewire. When introduced in 1995, Firewire, one of many electronic protocols for A/V also referred to as iLink, IEEE1394 or 1394, provided both the transfer speed, at 400Mpbs, and the consistency needed to allow the average user to edit video on their PC. As opposed to NTSC, there is no limit to resolution so images or movies as wide as 4000 pixels are easily obtainable with the digital cameras we sell for microscopy. The consistency of delivery is the crucial advantage that digital video has over analog video when it comes to working with images on a PC. On the receiving end of this data transmission, there is no translation or interpretation, just the delivery of pure data. NTSC can only deliver 720 pixels wide video or stills from video.ĭigital video, or DV, on the other hand, remains digital (such as '0's and '1's ) with the data describing the colors and brightness of each video frame. This process can introduce a progressive loss of data leading to a general loss of video quality. The analog process encodes video and audio in complete frames (modulation), with the receiving device interpreting and translating the signal into video and audio on a monitor (de-modulation).
Analog or Digital Video: What's the difference?