A method for encoding data includes: receiving a frame of data including subunits; initializing a remaining bit budget for the frame; setting a current codec to a lossless codec having a lossless codec bitrate; and sequentially encoding the subunits, including: encoding a first subunit using the lossless codec to compute a first encoded sub-unit; subtracting a length of the first encoded subunit from the remaining bit budget; determining whether the remaining bit budget exceeds a first lossy bits required to encode a plurality of remaining subunits using a first lossy codec having a first lossy codec bitrate lower than the lossless codec bitrate; in response to determining that the remaining bit budget is less than or equal to the first lossy bits required, setting the current codec to the first lossy codec; and encoding a second subunit using the first lossy codec to compute a second encoded sub-unit.