There have been not just one but two recordings so far of the Office chants by Dufay for the Recollectio BMV; however Haggh's promised facsimile seems to be lagging and the new Works volume probably won't be out for a while. Neither have I found Cambrai, Bibliothèque municipale, XVI C4 online, though Cantus lists some concordances to different melodies.

All of this is making me antsy, for Aug. 5 falls on a Sunday this year and I have in the back of my mind offering to bring some music to my grandfather's parish, Our Lady of Snows in Westwood CA. Is anyone out there celebrating the feast? The plan of last resort is of course to transcribe from the recording; here's a first stab at Vidi speciosam:

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commentary: Vidi speciosa;
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(c4)
Vi(fff/eDCdf)di(f.) * spe(f)ci(e)o(fghf)sam(f.) si(ixih)cut(g) co(f)lum(g)bam(f)
a(h)scen(j)den(jk)tem(j.) de(ixjkjhi)su(h)per(h) ri(h)vos(ixij) a(h)qua(ixih)rum:(gf.) (:) cu(c)jus(d) in(f)æs(f)ti(f)ma(g)bi(f)lis(f) o(e)dor(f) e(gh)rat(f) ni(fe)mis(dc.) in(f) ves(f)ti(g)men(ixhi)tis(h) e(hg)jus(h.)
et(j) si(j)cut(k) di(j)es(h) ver(ixih)ni(g.) cir(f)cum(g)da(ixhij)bant(h) e(hg)am(h) flo(fg)res(f) ro(fd)sa(ef)rum(c) (;) et(cd) li(ff)li(gf)a(f) con(fe)vel(ixfghih)li(gf)um.(f) (::) Ma(f)gni(gh)fi(h)cat...(h)