I have captured a vhs with this script under Linux



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?


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.


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