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The difference between analog video capture card and digital capture card

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Author : PURPLELEC
Update time : 2024-06-25 10:57:09
  The ana-log acquisition card collects ana-log video signals into the PC through the AV or S terminal, converting the ana-log signals into digital signals. The video signal source can come from ana-log cameras, TV signals, ana-log video recorders, etc.
  The digital acquisition card collects digital video signals losslessly into the PC in the form of digital to digital through the IEEE1394 digital interface. The video signal source mainly comes from DV (digital video camera) and other digital devices.
acquisition card
  The effects of ana-log video acquisition cards and digital acquisition cards in collecting video signals mainly have the following differences:
  1. Signal quality:
  • Ana-log acquisition card: It receives ana-log video signals through AV or S terminals, and then converts these signals into digital signals. In this conversion process, due to the influence of factors such as the accuracy and anti-interference ability of the ana-log-to-digital converter (ADC), the ana-log signal will be lost, resulting in the final collected digital video quality is usually lower than the original ana-log signal.
  • Digital acquisition card: directly receives digitized video signals through digital interfaces (such as IEEE1394, HDMI, etc.). During this process, the signal remains in its original digital form. In theory, there is no signal loss, which can ensure that the acquired video is consistent with the original video source.
  2. Signal fidelity:
  • Ana-log acquisition is like ripping a videotape. Each conversion may introduce noise and distortion, especially after multiple transcriptions, the image quality will gradually decrease.
  • Digital acquisition is like copying a computer file. No matter how many times it is copied, the new file is exactly the same as the original file, because digital signals can be transmitted and copied losslessly under ideal conditions.
  3. Compatibility and flexibility:
  • Digital acquisition cards can usually be better used with modern high-definition video equipment (such as DV cameras, high-definition cameras, etc.), supporting higher resolutions and more advanced encoding and decoding technologies.
  • Ana-log acquisition cards are more suitable for old ana-log devices, such as VCRs, early closed-circuit television systems, etc.
  4. Post-processing and transmission:
  • Digitally captured videos are easier to edit, compress, transmit and store, and are suitable for professional video production and long-term archiving.
  • Ana-log-captured videos may require more signal processing steps before post-editing, and the quality may be further reduced during storage and transmission.
  To sum up, digital capture cards are superior to ana-log capture cards in terms of signal quality, fidelity, and convenience of post-processing, but this also means that the cost and technical requirements may be higher. The choice of which type of capture card should be determined based on the specific application scenario, device compatibility and budget.