Interlaced video vs interlaced and already de-interlaced-difference ?

[rodling]

To elaborate what I mean.....

Is there a technical difference between a video that is interlaced, and one which was interlaced in the past but has already had a de-interlacing method permanently applied to it ? Does windows or video players distinguish between the 2 ?

Sometimes when I have videos with a lot of "mouse teeth" it doesn't seem like applying a different de-interlacing method does much of anything, which makes me wonder if the video player can recognize the original interlaced frames or is just seeing it now for what it is.

[davexnet]

There would normally be some indicator within the file that the media player can read to see if the file is marked as interlaced.
If no indicator is set, it's treated as progressive
You can check the file with mediainfo to see what it's marked as

[rodling]

oh, I just did this and the source video was marked progressive :/

no wonder. It was an online academic video, I hate
when they use poor video storage.