Video Transfer

The first thing that you need to do when you want to edit your movie with a PC is to transfer your footage to the hard drive of your PC. This article will discuss the different ways that are available to do that.

1. Digital Video Transfer

If your source material is DV (miniDV or Digital-8) your life is easy. Every camcorder can output the digital video and audio through its Firewire port. The only thing you need is a Firewire connection on your PC. Most PC’s sold these days are already standard equipped with Firewire. If it has not, you can buy one and easily mount it on a PCI slot, assuming you have still one available. Such cards are sold for around $25, including some basic video editing software or more expensive if it is accompanied with a more sophisticated editing package. Firewire is supported by Windows 98SE and later Operating Systems.

The compression format used on DV tape is also used to store the video on your hard drive, so this process is a direct transfer. There is no digitizing or decompression/compression involved so there is no loss of quality. In order to perform the task, you will need a software program to control the transfer. All current video editing packages will have a module that will do that. Windows XP is even shipped with Microsoft MovieMaker with which you can also do it.

Nice feature of Firewire is that it also allows Device Control. Hook up your digital camcorder and you can control all functions of your camcorder through your computer like play, stop, fast forward and rewind. You actually can perform functions, which you cannot perform directly on your camera like slow play, play backwards, step frame by frame etc.

After the transfer you will end up with a DV compressed AVI file containing both video and audio.

Batch capturing

During recording on digital tape, camcorders can store a timecode on the tape. This timecode is not visible on the video but can be read by the camera. As long as you don't leave any blank space on the tape, the timecode will be uninterrupted and can then be used for batch capturing. The way it works is that you browse the tape with your video editing program using Device Control and set IN- and OUT-points defining segments that you want to transfer. After defining all the required segments, you start the actual batch capture which transfers all the defined segments without any need for human interference. The tape will rewind to the first IN-point start playing from there until the first OUT-point while transferring the video. Then the tape will fast forward to the next IN-point. The process continues until all segment have been transferred.

2. So what about transfer over USB?

Many miniDV camcorders also contain a USB port. Some years ago, they were only used for transfer of pictures taken on a memory card. But newer models also can transfer video from the tape over USB and manufacturers advertise with it as fast streaming video. In principle USB 2.0 is fast enough to transfer DV in real time, but the issue is that the transfer rate of USB is controlled by the CPU of your PC and therefore can drop below the required rate if other processes take CPU capacity. In order to keep it reliable, the transfer through USB that was introduced by camcorder manufacturers, is based on the same principles as used for webcams. The video is compressed to a lower quality level and then send to the PC which captures the frames and stores them in a file. The transfer rate of Firewire (both the a-type and the b-type) is not controlled by the system but by the bus itself and will therefore always stay at the required level for a transfer of full quality DV.

Another issue with USB is that you will have to install a separate driver on your PC in order to communicate with the camcorder and even with these drivers installed, many video editing or capturing programs will not recognize a camcorder connected over USB. The camcorders with the ability to stream video over USB are therefore usually delivered with separate video editing software for use with the camcorder.

Bottom line is that you should always should use Firewire to transfer from miniDV to PC for best quality.

3. Analog video capturing

In order to transfer analog material like VHS or Hi-8 to your PC it will need to be digitized. This process is called capturing.

One of the ways to do it, is by installing a special capture card in an available PCI slot in your PC. Such a card contains an analog input connection to hook up your video source. There are basically two types of connectors: Composite and S-Video. If you have a choice you should use S-Video because it offers a slightly better transfer quality. Some capture cards are equipped with an audio input, but others are not. In the latter case you will need to use your standard line-in of your sound card. One issue that you may encounter in this case is that video and audio become out of sync after some time of continuous capturing. You can prevent that by capturing in shorter sections e.g. 5 minutes. Most capture cards contain video compression hardware, which digitizes the footage using a certain compression format. A popular format from the analog age was a MJPEG compression (not to be confused with MPEG).

Other cards, for example TV-in cards, will allow you to compress the footage with a software compressor. In this case the compression is performed by the PC’s processor, which must then be powerful enough to keep up with the incoming video data. Modern generation processors will have no problems to perform the task. More recent capture cards, which usually are combined with a Firewire port, allow you to compress the material using the DV-format. A second option is to buy one of theses special devices which you connect to the USB or Firewire port of your PC. Typical examples are the Dazzle Break-out boxes. Some of these boxes offer various compression formats. If you want to buy one to digitize analog video, make sure it can output DV-compressed video. Some devices compress directly to MPEG which is more difficult to edit.

An interesting option is to do a Pass-through, using a digital camcorder as a bridge between the analog source and PC. The output of the analog source is connected to the analog input of the digital camera, which is connected to the PC using the Firewire connection. The digitizing process is carried out by the digital camcorder and the digital video/audio is output directly to the Firewire port. In order for this to work, the analog port in the digital camcorder needs to be bridged to the Firewire port. This is not the case with all camera's out there.

Analog camcorders have no Device Control, you can not control them from your PC. Batch capturing is therefore also not possible.

4. Some system considerations

Storing video on a hard drive takes a lot of space. The exact amount depends on the compression format and ratio, but standard DV-AVI for example takes about 2GB for 9 minutes. You should therefore have a hard disk with sufficient capacity. An issue to take into consideration is that the hard drive should be NTSF formatted. Hard drives using the old FAT formatting as used by default in the older Operating Systems like Windows 95 have a file size limitation of 2GB, which is very impractical.

One of the things that you want to avoid, is dropping of frames. This happens if your system is not fast enough to keep up with the incoming data. A couple of things can be done to prevent dropped frames:

• A void running heavy CPU consuming processes while transferring video.
• Use a hard drive that is fast enough. Fortunately, modern hard drives can easily handle the amount of data transfer, but if you have an older hard drive you may have to buy a new one.
• Use separate hard drive for you video. Specifically avoid to use the hard drive on which the operating system is installed (usually the C-drive).
• Make sure that your hard drive is defragmented before transferring. This is certainly a good idea when the hard drive becomes very full.

Not too long ago, you really had to make sure to assemble your PC selecting all components carefully to make sure that the machine is suitable for video editing. Modern machines however all have sufficient power to do video editing without any problems.