Any way of quantifying quality loss when capturing DV via A/V and not FireWire?
I have a cheap Analogue/Digital converter taking the signal from the A/V output of a video recorder (or analogue camcorder) and pushing it into the computer via USB as an .mp4 file.
With analogue footage it does an excellent job being indistinguishable from the original but of course with digital video there is a noticeable quality loss.
Is there any objective measurement of this loss such as a 768x 576 original looks like a 480p or 360p copy?
So are there any objective figures that show the equivalent output or is it one of those things that varies from camera to camera?
A google search came up with the following which apart from saying it will be worse is very vague about how bad.
When copying DV video through the A/V output, you will experience a significant loss of quality compared to a direct digital transfer (e.g., FireWire). The A/V output is analog, while DV is inherently digital. This conversion introduces multiple potential quality degradations, including:
- Analog-to-digital conversion:
- The analog signal from the A/V output is converted to a digital signal by the capture device, which introduces noise and artifacts.
- Lower bandwidth:
- The A/V output typically has lower bandwidth than a digital connection like FireWire, meaning less information can be transmitted.
- Interlacing issues:
- If the DV format is interlaced, the A/V output might not preserve the correct interlacing, leading to visible artifacts.
- Further compression:
- The A/V output itself might involve some compression, further reducing quality.
In contrast, a direct digital transfer via FireWire or other digital interfaces (like HDMI on some HD camcorders) allows for a near-perfect copy, retaining the full resolution and quality of the original DV video.
According to a Reddit thread r/VideoEditing
, using A/V output can result in a "worse version" of the video compared to a digital transfer.
In summary, copying DV via A/V output results in a noticeable loss of quality compared to a digital transfer due to the analog-to-digital conversion, reduced bandwidth, and potential interlacing issues.
Mac mini
