Add minus sign to event_start_idx in atsc.counting.data line 240 (#2)

Co-authored-by: Stefano Damiano <stefano.damiano@esat.kuleuven.be>

atsc/counting/data.py

@@ -237,7 +237,7 @@ def __getitem__(self, item: int) -> dict[str, Tensor | int]:
 
             if event_start_idx < 0:
                 # Event starts before the beginning of the segment
-                event_audio = event_audio[:, event_start_idx:]
+                event_audio = event_audio[:, -event_start_idx:]
                 audio_segment[:, : event_audio.shape[-1]] += event_audio
             elif event_start_idx + event_audio.shape[-1] > audio_segment.shape[-1]:
                 # Event ends after the end of the segment