Body: <p>When I capture a video from my VCR (a Sharp VC-M401SM) with an S-Video cable connected to a SCART adaptor (like the one shown in <a href="https://video.stackexchange.com/q/29933/29303">this post</a>) I obtain a gray-scale image.</p>
  <p>One possibility for this is that the VCR is not capable to output an S-Video signal. To understand if this was the true reason I compared some couples of images composed by:</p>
  <ul>
  <li>the gray-scale image obtained using the S-Video cable;</li>
  <li>an image obtained by acquiring a colored image from the composite signal and then converted to grayscale.</li>
  </ul>
  <p>Here is one example:</p>
  <p><a href="https://i.sstatic.net/Cwhrb.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Cwhrb.png" alt="First image" /></a></p>
  <p><a href="https://i.sstatic.net/EHr0l.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/EHr0l.png" alt="Second image" /></a></p>
  <p>It seems to me that there are little differences between the two images. I guess that these differences result from noise and from color to gray-scale conversion. This makes me think that the quality of the images is comparable.</p>
  <p>Therefore I conclude that the gray-scale output when using the S-Video cable is not due a problem in the croma component, but instead due to the fact that the VCR does not support the S-Video output.</p>
  <h3>Questions</h3>
  <ul>
  <li>Is my reasoning correct? Can we conclude from this test that the VCR does not support S-Video?</li>
  <li>If not, what can we conclude instead?</li>
  </ul>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-05-08T11:23:28.270Z
Comments.Text: You are likely comparing the same signal against itself, see https://allpinouts.org/pinouts/cables/audio_video/scart-to-rca-and-s-video-adapter/ - SCART pin 19 carries the identical signal to both connectors. So it's a question of whether SCART pin 15 (chrominance) is carrying any signal.
Comments.UserDisplayName: Peter Barton
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-05-31T07:51:14.720Z
Comments.Text: Thanks for the suggestion. I just checked that the SCART pin 15 was not cabled inside the VCR. So I conclude that the differences in the two images above is only due to noise.
Comments.UserDisplayName: simonet
Tags: <video-quality><video-recording><cable><vhs>
Title: Testing if VCR supports S-Video by image comparison. Is it correct?
UserDisplayName: simonet
ThreadText: # Testing if VCR supports S-Video by image comparison. Is it correct?
  
  (Asked by: username_0 on 2020-05-07)
  
  When I capture a video from my VCR (a Sharp VC-M401SM) with an S-Video cable connected to a SCART adaptor (like the one shown in [this post](https://video.stackexchange.com/q/29933/29303)) I obtain a gray-scale image.
  
  One possibility for this is that the VCR is not capable to output an S-Video signal. To understand if this was the true reason I compared some couples of images composed by:
  
  * the gray-scale image obtained using the S-Video cable;
  * an image obtained by acquiring a colored image from the composite signal and then converted to grayscale.
  
  Here is one example:
  
  [![First image](https://i.sstatic.net/Cwhrb.png)](https://i.sstatic.net/Cwhrb.png)
  
  [![Second image](https://i.sstatic.net/EHr0l.png)](https://i.sstatic.net/EHr0l.png)
  
  It seems to me that there are little differences between the two images. I guess that these differences result from noise and from color to gray-scale conversion. This makes me think that the quality of the images is comparable.
  
  Therefore I conclude that the gray-scale output when using the S-Video cable is not due a problem in the croma component, but instead due to the fact that the VCR does not support the S-Video output.
  
  ### Questions
  
  * Is my reasoning correct? Can we conclude from this test that the VCR does not support S-Video?
  * If not, what can we conclude instead?
  
  **Tags:** video-quality, video-recording, cable, vhs
  
  > **Comments:**
  > **username_1**: You are likely comparing the same signal against itself, see https://allpinouts.org/pinouts/cables/audio_video/scart-to-rca-and-s-video-adapter/ - SCART pin 19 carries the identical signal to both connectors. So it's a question of whether SCART pin 15 (chrominance) is carrying any signal.  
  > **username_0**: Thanks for the suggestion. I just checked that the SCART pin 15 was not cabled inside the VCR. So I conclude that the differences in the two images above is only due to noise.  
  
  ---
  
  ## 0 answers
  
  