Lossless compression of high quality audio and music

Abstract

Numerous audio recordings that are part of the Maltese audio heritage are in danger of irrecoverable damage since they are stored on analog media prone to deterioration. These audio recordings are also underused due to their lack of accessibility. This situation gave rise to the aims of this final year project which tries to achieve both preservation and accessibility through digitization. The project aims to find the most adequate lossless audio codec that can be used to compress and preserve the Maltese audio heritage and also aims to make these priceless recordings available to the general public through the implementation of an Online Music Library. Through the literature survey conducted in the project, it was concluded that the best audio codec for the archival of Maltese audio and music is the MPEG-4 Scalable to Lossless Audio Codec (MPEG-4 SLS). This codec is a hybrid codec which offers both a two layered solution and a pure lossless single layered audio solution. The two layered solution comprises of a lossy AAC stream and a lossless SLS stream which are multiplexed together in order to achieve backwards compatibility. The other solution is referred to as 'non-core mode' as here the codec operates without the core AAC stream. The MPEG-4 SLS audio codec was modified in order to obtain a single encoder that is capable of encoding PCM audio both into a lossy and a lossless compressed bit stream. The lossy bit stream was merged together with song lyrics and related images in order to create a video. This video together with the lossless non-core stream generated by the modified codec were made available to the general public by implementing an Online Music Library website. This website has two main sections, one being a 'view videos page' and the other being a 'downloads page'. The 'view videos page' allows all users to search for Maltese music and view the videos mentioned previously. On the other hand, the 'downloads' page allows authorized users to search and download the fully lossless audio stream, together with any other related material. Thus through the implementation of the Online Music Library, the Maltese audio heritage is made more accessible to the general public and thus it will get the appreciation it truly deserves.