I played in a match today and unfortunately there was a line call I made that dampened the mood of the remainder of the match. Luckily we recorded the match so I was able to look back at it. However, the video doesn't change my mind and I stand by the call but want to hear other opinions as if there is a consensus that the ball was "in", I'd like to apologize to my opponent.
From my perspective, as I was running to the ball I saw it clearly land in the blue a few centimeters out. I wasn't stretched for the ball and had a clear look at it since it was a down the line shot.
It doesn't matter what the rest of us say because only you were there and only you have to make the call. Just call 'em like you see 'em and give the benefit of the doubt to your opponent.
Note that your opponent has a better view of the ball because A) he's relatively static while you are moving; and B) his line of sight is parallel to the ball's trajectory and the line whereas you're moving at an angle. The compensating factor is that you're closer.
Also keep in mind Vic Braden's research about how the ball can roll up to 2" after landing and that our visual system is not granular enough to catch all of that. You may see where the ball landed but you might also see after it has rolled a bit. This makes way more of a difference when the ball passes a line parallel to you, like the BL. It's less of a factor when the line is perpendicular.
However, after reading that research, I have become more generous with my line calls because I can't know exactly when I saw the ball land.
I was once in your opponent's position and I had just passed the guy at net DTL. I had the better view and he deferred to me to make the call; I called it out because that's what I saw.
FWIW, I saw the ball in. But the net strap is partially blocking the landing point, it's far away, and film resolution and speed is too low to make an accurate call. And I have the luxury of single-stepping through the video multiple times. You don't have that luxury.
BTW: it shouldn't have dampened the mood of the match unless he was mad about previous calls you had made. It's just one call and you're both presumably doing your best to make accurate calls. No one is perfect.