Roy can still be seen playing with Whiteman though! He's more or less in full view for over 40 seconds, playing oboe and flute in the 1928 "My Ohio Home" newsreel fragment. This is available on DVD: "At The Jazz Band Ball", Yazoo 514 (Amazon has it).
An edited version of these 40 seconds can be found at http://www.youtube.com/watch?v=RmD7jeIEkfg&feature=PlayList&p=6DC2EB349771BF7B&playnext=1&playnext_from=PL&index=10
Roy's bit starts at 1:02, he's the guy sitting under the clock. He plays a few solo notes on his oboe, then puts it down. The Youtube edit makes him disappear for about 20 seconds in order to get a close up of Bix, then Roy's back again for another 15 seconds, playing flute. Those missing 20 seconds show him picking up his flute, looking around, and checking the instrument before playing. Incidentally, the image on DVD is much sharper than the one on Youtube. Roy's features are clearly recognizable on the DVD version, which also shows he has his bassoon in his lap all the time.