[FFmpeg-user] Meaning of ffprobe output

Carl Zwanzig cpz at tuunq.com
Wed Jan 30 19:27:38 EET 2019

On 1/30/2019 6:12 AM, Carl Eugen Hoyos wrote:
> You may have forgotten that while the vertical resolution is kept,
> horizontal resolution is reduced significantly for VHS, likely
> confusing the algorithm for detection of interlaced content.

Exactly, VHS only has bandwidth of ~3MHz, so a horizontal resolution of ~240 
TV lines (not pixels). There can also be a -lot- of variable horizontal 
smearing (plus other artifacts).

AFAIK all VHS players produce an interlaced signal, composite and optionally 
S-video; the concept of "progressive scan" does not apply to an analog video 

There are many pages about capturing analog recordings- going from one lossy 
format (analog VHS) to another (DVD/mpeg) will not generally yield good results.


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