The first DVD writers have been build in September 1997. The DVD support code for cdrecord has been written in February 1998 using a borrowed sample with serial number 35 from Pioneer. This happened after ESO did like to get software to write DVDs on UNIX using data from the telescopes of the VLT project.
At that time, DVD writers have not been sold to the public. A drive was ~ 16,000 US $ if you did get the permission to buy one and a blank medium was ~ 80 US $.
The DVD support software, I wrote was covered by an NDA with Pioneer and the drives have not been sold to the public. At that time, it did neither make sense to publish the source nor did I have the permission to do so. Binaries have been given to the rare customers of DVD writers.
Starting around Autumn 2001, a new third generation of DVD writers was sold for less than 1000 US $. The media price was now only ~ 15 US $ and a lot of people started to get interest in DVD writing.
At the same time, three companies did steal either the complete cdrecord source code or parts of it and put it into closed source proprietary MS-WIN applications. I tried to sue the companies to no avail. The two smaller companies did lift and for the bigger company it was not possible to get the binaries (that only have been presented on a press conference). It turned out, that the GPL does not protect against this kind of piracy. Later, Harald Welte did only hand pick companies with different constraints to allow him to win a case....
As the bigger company did not have own DVD writing support code at that time, I decided to keep the source secret until this company did develop own DVD writing code and meanwhile did give away cdrecord-ProDVD binaries for free starting on October 16th 2001. At that time, I did have many discussions with Heiko Eißfeldt and we decided to make the cdrtools available under a more free license than the GPL, once the DVD support code was made OpenSource. The reason for this decision was that the restrictions in the GPL do not really prevent companies to illegally use code from GPLd projects.
Finally, the DVD support code could have become OpenSource earlier if not some self called
OSS activists constantly tried to push me for opening source code.