Sorry, I missed the status line at the bottom. It is as I suspected. The transient filter is the only thing implemented and none of the reverse engineered software implementations deal with those filters.
JRiver decided not to identify tracks as HDCD if they were not encoded with peak extend and/or gain adjustments. foobar identifies the HDCD marker but does not apply any HDCD extensions since there is no HDCD code that it can expand. I believe that is why foobar identifies this CD as HDCD and MC does not.
A little history - well actually a lot of history.
Pacific Microsonics developed HDCD and implemented it in their A to D converters. They then licensed the decoder to a chip manufacturer and CD player manufacturers used that chip to decode HDCD. PM never disclosed the full details of the HDCD encoding and decoding. When HDCD was declining, Microsoft purchased the rights to HDCD and, again, never disclosed the details. Microsoft did implement a software decoder in Windows Media Player.
One enterprising software expert reverse engineered a program, which he called hdcd.exe, and that got into the public domain. He never had the actual specs for HDCD, he just did everything he could to try to reproduce the output of the WMP decoder and the HDCD players. He basically reproduced the peak extend and gain adjustments parts of HDCD. However, the transient filters were pretty much unknown and the were only implemented when the data was upsampled to 88 Khz by the CD players. Since he did not know what the filters really were he did not try to implement them and did not upsample to 88 KHz. The hardware CD players only output the end analog signal. They did not produce a digital signal that could be analyzed. That was common in the days before computer audio, since the only DACs were in CD and other players. This original reverse engineered version is commonly referred to as the doom9 version, since that website is where the original version was discussed and released.
Early adopters like dBpoweramp used the hdcd.exe program just as it was released. But the code was never made public as far as I know. hdcd.exe only ran on Windows systems, so it was not implemented on Apple systems, except perhaps using Windows emulators.
A latter reverse engineering of the Microsoft decoder lead to a second reverse engineered software decoder and that was implemented in foobar. Since the code for that program was available, it could be used across platforms, including on Apple. Once again, it only did peak extend and gain adjust, based on the research done by the hdcd.exe author.
JRiver implemented the foobar version of the code, since they wanted it to be cross platform. However, they added the idea that if no peak extend or gain adjustment was encoded in the track, then they would not identify it as HDCD, since the hdcd decoder did nothing to the bits.
There are many CDs labeled as HDCD which have no HDCD content. That is because lots of studios used PM A to D converts, which were state of the art. However, the engineers often did not really understand HDCD so they just ignored those options in the A to D. But the A to D still wrote the code to the track that identified it as a HDCD track. Sometimes these producers identified the disk as HDCD and sometimes they did not. But, since the marker was present in the files, the blue light lite on CD player, even though nothing was really being enhanced.
In the case of your CD and others from the same producers, it appears that they did not apply any peak extend or gain adjust but did implement the transient filters. Hence, HDCD players, dBpoweramp and foobar identify them as HDCDs, even though only the transient filters are implemented on the original CD.
In summary, there are two software decoders generally available and both are reverse engineered without the advantage of having the full specs or the original code. JRiver used one of those and further added the feature to not identify the tracks as HDCD if no HDCD changes were actually made.
Hope that helps, a little.
EDIT: I forgot to mention the ffmpeg HDCD decoder. From what I understand, it is based on the foobar decoder.
Author
Topic: JRiver does not identify HDCD encoded disc as being HDCD-encoded (Read 3197 times)