
In reality, however, soundtrack producers remain ambiguous about this distinction, and titles in which the music on the album does lock to picture may be labeled as OCS and music from an album that does not lock to picture may be referred to as OMPS.
The phrase "recorded directly from the soundtrack" was used for a while in the 1970s, 1980s and 1990s to differentiate material that would lock to picture from that which would not (excluding alternate masters and alternate vocals or solos), but again, in part because many 'film takes' actually consisted of several different attempts at the song and edited together to form the master, that term as well became nebulous and vague over time when, in cases where the master take used in the film could not be found in its isolated form, (without the M&E) the aforementioned alternate masters and alternate vocal and solo performances which could be located were included in their place.
As a result of all this nebulosity, over the years the term "soundtrack" began to be commonly applied to any recording from a film, whether taken from the actual film soundtrack or re-recorded in the studio at an earlier or later time. The phrase is also sometimes incorrectly used for Broadway cast recordings. While it is correct in some instances to call a "soundtrack" a "cast recording" (since in most cases it contains performances recorded by the original film cast) it is never correct to call a "cast recording" a "soundtrack."
Contributing to the vagueness of the term are projects such as The Sound of Music Live! which was filmed live on the set for an NBC holiday season special first broadcast in 2013. The album released three days before the broadcast contained studio pre-recordings of all the songs used in the special, performed by the original cast therefrom, but because only the orchestral portion of the material from the album is the same as that used in the special, (i.e. the vocals were sung live over a prerecorded track), this creates a similar technicality because although the instrumental music bed from the CD will lock to picture, the vocal performances will not, although it IS possible to create a complete soundtrack recording by lifting the vocal performances from the DVD, erasing the alternate vocal masters from the CD and combining the two