There was a time when composing and producing orchestral music meant huge effort, thousands of dollars and a lot of time invested. And while you can still do it that way, many modern DAWs offer a considerably more effective alternative. By understanding MIDI programming and using suitable virtual instruments and libraries, anyone can work with orchestral instrument sounds and parts. In this video from the course The Orchestral Sessions 102: Prep, Notation And Parts, Olajide Paris shows you the importance of quantizing MIDI for a believable end result when programming.
In the video, Olajide explains the concepts of regions and events - both different aspects of MIDI data, and how each one can be quantized to correct or control its timing and feel. Sometimes it's appropriate to quantize individual MIDI events (notes) or clips and in other cases, different regions within a clip or a project (which contain multiple notes) will require a different treatment, as their timing, length and feel may need to differ.
The reason this distinction is important - with any MIDI, not just orchestral programming - is that notes may well be based on different subdivisions of time. So one string part might be made up of rapid staccato notes, but another might be slower and use a different rhythm. Quantizing them all at once would likely mess up one or both of them. Quantizing them individually gives you much more control. Once you have learned about these quantization techniques, check out the rest of the course for a comprehensive guide to prepping your MIDI parts for orchestral performance!