This video was uploaded on Mar 30 and is said to be from Homs. Bjørn believes the tank has fired one round just before the video starts – and later the footage shows three more rounds being fired.
The tank seems to be a T-72, but the video is a low-resolution one to rule out any other Russian T-model.
Four frames from the video posted above showing smoke after one tank shell fired (sec 0:01) and three more shell being fired (sec 0:13, 0:41, 1:17). Source: hoole19 YouTube channel.
Left: image of a 125 mm tank shell from here. Right: frame from video posted above.
Assuming it’s a T-72 it will most likely have a 125 mm smoothbore main gun, and it could be firing shells like the one in the image above. More examples here.
It is not clear to me what has happened up to this, but during the video there is no sounds of other weapons being fired or any other sign of provokations, which make it look like this shelling is random terror.