Revert "Revert "Correctly detect alac in mp4 properties""

This reverts commit 6265048ae8665189ea88262cd3aedd2d03abce35.

modules/demux/mp4/mp4.c

@@ -2032,6 +2032,11 @@ static int TrackCreateES( demux_t *p_demux, mp4_track_t *p_track,
                             p_sample->data.p_sample_soun->p_qt_description,
                             p_track->fmt.i_extra);
                 }
+                if( p_track->fmt.i_extra >= 56 && p_sample->i_type == VLC_CODEC_ALAC )
+                {
+                    p_track->fmt.audio.i_channels = *((uint8_t*)p_track->fmt.p_extra + 41);
+                    p_track->fmt.audio.i_rate = GetDWBE((uint8_t*)p_track->fmt.p_extra + 52);
+                }
                 break;
 
             case VLC_FOURCC( 'v', 'c', '-', '1' ):