擷取來自VHS放影機的訊號:

請先參考:
http://www.digitalfaq.com/source/understandsource.pdf
3. VHS. The Video Home System (VHS) format was invented by Victor Company of Japan (JVC) in 1976. VHS is
a relatively weak quality recording operating at 3.0MHz, and at a meager 220x480 (EP mode) to 240x480 (SP
mode) resolution. VHS is interlaced and operates at a standard 29.97fps. Audio quality is approximately 44.1hz.
2. VCD MPEG-1. 352x240 does not equal VHS quality because it cannot be interlaced. In fact, the entire
VCD=VHS analogy is little more than an urban myth because there are numerous flaws in the comparison,
mainly with interlace and resolution. A true VCD is 352x240 with a bit-rate of 1150k CBR at 29.97fps. PAL
version is 352x288 progressive at 1150k and 25fps. A VCD MPEG-1 is low quality and already full of
macroblocks, so therefore should not be re-encoded if at all avoidable.

http://www.digitalfaq.com/capture/decideresolution.pdf
VCD does not equal VHS. That is a myth perpetuated by misinterpretation of analog "lines of
resolution" and how it fits into the digital realm. While 240 is a number used in both the VCD
resolution and VHS lines of resolution, they represent opposite axes. VHS is also interlaced while
VCD is progressive.

http://www.digitalfaq.com/capture/droppedframes.pdf
9. VHS source. Garbage in, garbage out. It's that easy. Often, VHS and VHS-C tapes can cause your system to drop frames. This is usually confined to old
tapes that have seen better days, but it can also apply to newer tapes. The information being fed into your video card is corrupt, and it will throw off your
system. Unfortunately, there is no fix for this. A TBC (time-base corrector) may correct the issues, but even then, that is not fool-proof. The number of frames
dropped for this reason should be a rather small number (maybe 10 per hour) and will probably happen close together because of a bad spot on the tape.