Answers.Body: <p>I have tested a 4:3 vhs, and using 5:4 a/r making screenshot report bad final a/r(1:22)</p>
  <pre><code>mplayer -aspect 5:4 -vf screenshot
  </code></pre>
  <p>using 4:3 a/r report in screenshot the correct ar(1:31:1)</p>
  <pre><code>mplayer -aspect 4:3 -vf screenshot
  </code></pre>
  <p>So I think the correct answer is 4:3.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-26T07:35:28.323Z
Answers.Text: PAL and NTSC both use non-square pixels, so the physical image width / physical image height ≠ number of pixels wide/ number of pixels high.  https://en.wikipedia.org/wiki/Pixel_aspect_ratio
Answers.UserDisplayName: Jason Conrad
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-26T02:42:09.900Z
Answers.LastActivityDate: 2021-02-26T02:42:09.900Z
Answers.UserDisplayName: elbarna
Body: <p>I have captured a vhs with this script under Linux</p>
  <pre><code>#!/bin/sh
  
  videodevice=&quot;/dev/video0&quot;
  alsadevice=&quot;hw:2,0&quot;
  
  v4l2-ctl -d /dev/video0 --set-ctrl mute=0
  
  v4l2-ctl -d /dev/video0 -i 1
  
  v4l2-ctl -d /dev/video0 --set-standard=PAL
  
  gst-launch-1.0 -q v4l2src device=&quot;$videodevice&quot; do-timestamp=true norm=&quot;PAL&quot; pixel-aspect-ratio=1 \
      ! video/x-raw,format=YUY2,framerate=25/1,width=720,height=576 \
      ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
      ! mux. \
    alsasrc device=&quot;$alsadevice&quot; do-timestamp=true \
      ! audio/x-raw,format=S16LE,rate=48000,channels=2 \
      ! queue \
    max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
      ! mux. matroskamux name=mux \
      ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
      ! filesink location=vhs.mkv
  </code></pre>
  <p>The final result is a raw avi, which I had to crop and resize to correct Aspect Ratio.
  The mediainfo program said is 5:4</p>
  <pre><code>mediainfo vhs.mkv |grep -i aspect
  Display aspect ratio                     : 5:4
  </code></pre>
  <p>But as I know the vhs is an old technology and in their times(70-80-90) the standard was 4:3
  I ask this because to determine the AR I usually do this</p>
  <pre><code>a)make a screenshot with mplayer
  b)open with gimp, select rectangle and I read the a/r (1.7777,1.6666,1.3333) in the bottom of program
  </code></pre>
  <p>the screenshot result different and return different a/r if I set with mplayer the a/r</p>
  <pre><code>mplayer -vf rectangle,screenshot -aspect 5:4 vhs.mkv
  mplayer -vf rectangle,screenshot -aspect 4:3 vhs.mkv
  </code></pre>
  <p>In your opinion I have to use 4/3 or 5/4?</p>
  
Tags: <vhs>
Title: VHS and capture: what is the real aspect ratio?
UserDisplayName: elbarna
ThreadText: # VHS and capture: what is the real aspect ratio?
  
  (Asked by: username_0 on 2021-02-25)
  
  I have captured a vhs with this script under Linux
  
  ```
  #!/bin/sh
  
  videodevice="/dev/video0"
  alsadevice="hw:2,0"
  
  v4l2-ctl -d /dev/video0 --set-ctrl mute=0
  
  v4l2-ctl -d /dev/video0 -i 1
  
  v4l2-ctl -d /dev/video0 --set-standard=PAL
  
  gst-launch-1.0 -q v4l2src device="$videodevice" do-timestamp=true norm="PAL" pixel-aspect-ratio=1 \
      ! video/x-raw,format=YUY2,framerate=25/1,width=720,height=576 \
      ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
      ! mux. \
    alsasrc device="$alsadevice" do-timestamp=true \
      ! audio/x-raw,format=S16LE,rate=48000,channels=2 \
      ! queue \
    max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
      ! mux. matroskamux name=mux \
      ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
      ! filesink location=vhs.mkv
  
  ```
  
  The final result is a raw avi, which I had to crop and resize to correct Aspect Ratio.
  The mediainfo program said is 5:4
  
  ```
  mediainfo vhs.mkv |grep -i aspect
  Display aspect ratio                     : 5:4
  
  ```
  
  But as I know the vhs is an old technology and in their times(70-80-90) the standard was 4:3
  I ask this because to determine the AR I usually do this
  
  ```
  a)make a screenshot with mplayer
  b)open with gimp, select rectangle and I read the a/r (1.7777,1.6666,1.3333) in the bottom of program
  
  ```
  
  the screenshot result different and return different a/r if I set with mplayer the a/r
  
  ```
  mplayer -vf rectangle,screenshot -aspect 5:4 vhs.mkv
  mplayer -vf rectangle,screenshot -aspect 4:3 vhs.mkv
  
  ```
  
  In your opinion I have to use 4/3 or 5/4?
  
  **Tags:** vhs
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2021-02-26. Score: 0 | Accepted answer
  
  I have tested a 4:3 vhs, and using 5:4 a/r making screenshot report bad final a/r(1:22)
  
  ```
  mplayer -aspect 5:4 -vf screenshot
  
  ```
  
  using 4:3 a/r report in screenshot the correct ar(1:31:1)
  
  ```
  mplayer -aspect 4:3 -vf screenshot
  
  ```
  
  So I think the correct answer is 4:3.
  
  > **Comments:**
  > **username_1**: PAL and NTSC both use non-square pixels, so the physical image width / physical image height ≠ number of pixels wide/ number of pixels high.  https://en.wikipedia.org/wiki/Pixel_aspect_ratio  
  
  ---
  
  