http://www.the-digital-audio.co.uk/master.htmBob Katz Book,
Mastering Audio is an excellent resource
* CD production master: your material is PQ coded(Code on a CD audio that indicates the length of the material and the location of each track.) and then transferred onto one of four formats; DDPi files on a DVD-R, DDP Exabyte, 1610/1630, or CDR.
o DDPi is the newest format. Disk Description Protocol files are generated and then burnt, together with Check Sum data, to a DVD-R and verified. Together with DDP Exabyte, this is the most reliable format and all data can be fully verified to ensure no errors creep in.
o DDP Exabyte is a very secure high speed computer data tape system which has been in use for many years by banks, etc. It too can be fully verified to ensure no errors creep in. It is becoming less come now as it is slower to use.
o 1610/1630 was the original format used for CD production. Digital audio is recorded via the Sony 1610 or 1630 processor onto a UMatic video tape. The data on the tape can be verified, but the tape is expensive, bulky and delicate. This system has almost been phased out, but we retain the ability to make new masters and transfer existing ones.
o Compact Disc Recordable (CDR). CDRs are ‘burnt’ with a special laser which heats up a layer under the surface of the disc, leaving a pattern of dots. There are several potential problems with CDR:
+ firstly many systems do not accurately transfer the data,
+ secondly any dust and contamination on the surface of the disc or airborne particles in the writer can prevent the laser from burning the correct pattern onto the disc (this can affect the sound of the CDs and may even mean some discs are unplayable),
+ thirdly most CDR systems cannot check the data which has been transferred, so you may not realise there is a problem until it is too late.
The Digital Audio Company uses either DDPi files on DVD-R or DDP Exabyte for CD production masters because it is very secure (we have never had a master fail!). We have run extensive listening and data tests, comparing original source material with production CDs to check that what the client supplies is what the final CDs sound like. We have never found any evidence of changes in sound when DDP is used.
Quality control is very important during CD pre-mastering. All CD masters are fully auditioned for audible problems either as they are loaded onto the edit system or played out. Our DAT machines have error indicators and the edit system analyses the digital audio for errors. As the master is being written it is automatically checked for data errors which are corrected. Once the master is written it is then verified (double checked) and for Exabytes and 1610 masters a report is printed to guarantee the quality. PQ coding is the process which adds extra information to the CD which tells the CD player where each song starts and stops, and its duration.
A CD can have up to 99 tracks and each track can contain up to 99 index points (although not all CD players can access indices).
It is also possible to embed a Bar Code number and International Standard Recording Codes (ISRC) into the table of contents on an audio CD to identify the owner of each track. ISRC's consist of a series of letters and numbers which are allocated by the PPL in the UK, and regulated worldwide by the IFPI. ISRCs can be used by radio stations, etc., to automatically log play out of your material for royalty payments. Visit their web site or for more contact information see our links page.
CD text is a relatively new addition to the CD specification and we can include information such as track title, composer, arranger and artiste when creating a DDPi master. Please ensure that you supply all CD text information with the correct spelling.
Topic: format question for CD duplication (Read 3555 times)