  In this paper, techniques for improving multichannel lossless coding are
examined. A method is proposed for the simultaneous coding of two or more
different renderings (mixes) of the same content. The signal model uses both
past samples of the upmix, and the current time samples of downmix samples to
predict the upmix. Model parameters are optimized via a general linear solver,
and the prediction residual is Rice coded. Additionally, the use of an SVD
projection prior to residual coding is proposed. A comparison is made against
various baselines, including FLAC. The proposed methods show improved
compression ratios for the storage and transmission of immersive audio.
