Yes! That's the exactly what I was looking for.
So, let's give an example. When creating new catalog, there is an option for filename pattern, by default, there is %a - %T - %t. But for my catalog of music, I decided to rather have it in %a - %A - %T - %t pattern.
Now, when creating m3u playlist using Stream mode, the file contains:
#EXTM3U
#EXTINF:216,Dave Matthews Band - I Did It and url. When I load m3u in my favorite player, it will display name of song from m3u file, but when the player actually starts playing that song, it will load the name in pattern specified in catalog. So it becomes Dave Matthews Band - Everyday - I Did It.
Now I wanted to Ampache created m3u playlist in this pattern. To do that, I edited line 313 to echo '#EXTINF:' . $url->time, ',' . $url->author . ' - ' . $url->album . ' - ' . $url->title . "\n"; and everything is fine now.
It might be worth try to edit that peace of code to respect Filename pattern, specified while creating a catalog.