UPDATE – Most of what is in this article is out of date, but offers some historical perspective of where we’ve come from. Some DV/HDV cameras are still in service, but mostly in an environment where their output is used (HDMI/SDI), in live streaming for example. Read this article for what it’s worth in the “HDTV transition” era.
The first step of any video project is to gather footage of your subject matter. For the past several decades video cameras have been using tape cassettes to save the video onto. In the mid-1990’s, a digital version of tape came into existence to facilitate the transfer to a computer for editing. As I write this in the summer of 2008, there are new storage forms that are gaining traction that do not use tape at all. We also
are going have gone through a transition of video resolutions from what is known as standard definition (SD) to high definition (HD) – and now on to 4K. This article will attempt to sort out the storage and resolution issues you should be aware of. When you’re ready to shop for a camcorder, check out the article on what to look for in a camcorder.
Where Digital Video Bits Get Stored
Let’s begin by talking about the ways in which cameras store the video that is recorded. We’ll start by mentioning what is thankfully fading into the past, and that is analog video. That means VHS (including S-VHS) and 8mm (including Hi8) videotape. I say thankfully because of the difficult nature of working with these formats in the digital world that we live in. The difference between these older analog formats and the relatively new digital video (DV) format is that a more complicated digitizing step needed to occur to get the video in a form that can be readily edited with a computer. With digital camcorders, video is already in a format that the computer can understand. The DV format also has the advantage of being higher resolution than either VHS or S-VHS (or 8mm and Hi8).
The disadvantage of the DV format is that there is no high speed transfer of the video to the computer. The digital information is on a linear tape. The video is all transferred in real time, meaning if you took an hour of video on the camcorder, it will take an hour to transfer it to the computer before you can edit it. That’s where some of the new storage formats shine.
In addition to the DV format, there are camcorders that store the video on mini-DVD (a smaller version of the standard DVD), on a hard disk drive similar to a computer hard drive, and on what is known as SDHC (Secure Digital High Capacity) flash memory cards which are removable. The advantage of all three of these formats is that you are simply transferring a file to the computer that has already been written to the DVD, hard drive, or SD card. Therefore transfers take fractions of the time it takes DV footage on tape to be transferred.
The disadvantage of these new storage formats is that you can quickly run out of space to store these digital files. A typical mini-DVD will hold up to an hour’s worth of video which is equivalent to a DV tape, but it is at lower quality. A typical hard drive camcorder might hold 5 hours of high-quality video, or an SDHC memory card may hold an hour or two, but what do you do after that. You can’t buy a new hard drive and insert it into the camcorder, and each SD card costs much more (at this time) than a DV tape does. DV tape does have an “archival” advantage over these other digital storage forms.
Other disadvantages come into play when you go to edit the video. Not all editing programs (especially the free ones) recognize the MPEG2 format from the recordable DVD, or the h.264 (aka AVCHD) codec from the SD cards, so be sure that you think about investing in an editor that can handle these formats.
Finally, don’t forget that many digital still cameras and even cell phones can do video too. However, you can only hold as much video as the storage in the camera or phone allows. Also, the video quality will not be nearly as good as DV or h.264 and it will probably be a slower frame rate.
Is It Time for High Definition?
As we move forward in the digital media era, the question of using the high definition (HD) level of video is one that comes up a lot. It generally has a higher cost in terms of more expensive cameras, and it is more time consuming and expensive to work with in editing. Both of those issues are constantly being reduced and soon “hi-def” will be the norm.
So what is high definition video, what are the benefits, and what are the issues? Well, good if somewhat technical information is available on Wikipedia. Generally it means video, in digital form, that has at least 720 vertical pixels of information. In most cases it also means a wide aspect ratio, so 1280×720 pixels would be common dimensions. Before hi-def came along, TV screens had an aspect ratio of 4:3. The screen was slightly wider than it was tall, but it looked square. Now with HD, the video has an aspect ratio of 16:9 which is more rectangular. There are also two levels of HD video. The 720 vertical pixel video, known as 720p (the “p” stand for progressive scan), and 1080 vertical pixel video, known as 1080p. There is also an interlaced version of the 1080 pixel resolution (1080i), and good information about the differences between progressive scan and interlace is also available at Wikipedia.
The benefits are clearer detail in what you are watching. You essentially have more information packed into a given space. The negative aspect is that HD files are bigger, and therefore take up more storage space. Also, if you were to download an HD video from the Internet it would require more bandwidth, or it would take longer to receive the file. You also need the right display device to watch HD video. Only the relatively new wide-screen digital LCD or plasma screens show you the advantage of HD video. A normal TV won’t show you the added detail.
Again, in the very near future, HD video will be the norm. You will need to decide whether to go with HD video for projects based on your audience. In June 2009, major television stations completely switched their broadcast signals to a digital form. They aren’t required to broadcast in HD, but the older analog TV sets will not work without a cable or satellite box, or converter box. Consult Wikipedia once again on the digital television transition.
For more information, see our article on what to look for in a camcorder.
Camera Photo by ivan castro guatemala
HD photo by pietel