  We use optical frequency comb Fourier transform spectroscopy to record
high-resolution, low-pressure, room-temperature spectra of formaldehyde
(H$_2$$^{12}$C$^{16}$O) in the range of 1250 to 1390 cm$^{-1}$. Through
line-by-line fitting, we retrieve line positions and intensities of 747
rovibrational transitions: 558 from the ${\nu}_6$ band, 129 from the ${\nu}_4$
band, and 14 from the ${\nu}_3$ band, as well as 46 from four different hot
bands. We incorporate the accurate and precise line positions (0.4 MHz median
uncertainty) into the MARVEL (measured active vibration-rotation energy levels)
analysis of the H$_2$CO spectrum. This increases the number of MARVEL-predicted
energy levels by 82 and of rovibrational transitions by 5382, and substantially
reduces uncertainties of MARVEL-derived H$_2$CO energy levels over a large
range: from pure rotational levels below 200 cm$^{-1}$ up to multiply excited
vibrational levels at 6000 cm$^{-1}$. This work is an important step toward
filling the gaps in formaldehyde data in the HITRAN database.
