I've just bought an RCA RP-5016A voice recorder. It is a nice gadget, and perfect in every way for what I want, except that it uses a proprietary file format and no software is supplied to export from this proprietary format to one understood by any other program. I've reverse engineered the file format enough to discover that in HQ mode it consists of 80 bit blocks, and in SP mode it consists of 56 bit blocks, each encoding 10 milliseconds of audio. I have verified that this is so, by reversing the order of the 80 bit blocks in a sample HQ clip, and noting that it then plays backwards. Does this sound familiar? Can someone help me decode this using open software under Linux? Or at least point me to an algorithm? Samples of me saying a few words in both modes are here: http://wandel.dyndns.org/rp5016a_samples e0000001.voc clip on HQ mode e0000001.rhq raw HQ (80 bit block) data with encapsulation stripped off e0000002.voc clip on SP mode e0000002.rhq raw SP (56 bit block) data with encapsulation stripped off Note that these are not Soundblaster .voc files, despite using the same filename extension. Can anyone help me? Email address in header is invalid. I am really markus(AT)pinetree(DOT)org Markus
Mystery voice codec: 10 millisecond blocks, 8 or 5.6 kilobits/second
Started by ●November 6, 2004
Reply by ●November 7, 20042004-11-07
nobodyhome@mailinator.com (Markus Wandel) wrote in message news:<4d3787c3.0411061421.4bb79dd6@posting.google.com>...> I've just bought an RCA RP-5016A voice recorder. > ... > I've reverse engineered the file format enough to discover that in HQ > mode it consists of 80 bit blocks... > ... > Samples of me saying a few words in both modes are here: > > http://wandel.dyndns.org/rp5016a_samples > > e0000001.voc clip on HQ mode > e0000001.rhq raw HQ (80 bit block) data (no encapsulation)After extensive googling, I've found only one standard speech codec with these characteristics, and it is G.729 CELP. I cannot, however, find any software that I can just download and experiment with. Could someone who does have such software run the raw data above through it, and tell me if it decodes? Email address in header is invalid. I am really markus(AT)pinetree(DOT)org Markus
Reply by ●November 8, 20042004-11-08
Markus Wandel wrote:> nobodyhome@mailinator.com (Markus Wandel) wrote in message news:<4d3787c3.0411061421.4bb79dd6@posting.google.com>... > >>I've just bought an RCA RP-5016A voice recorder. >>... >>I've reverse engineered the file format enough to discover that in HQ >>mode it consists of 80 bit blocks... >>... >>Samples of me saying a few words in both modes are here: >> >>http://wandel.dyndns.org/rp5016a_samples >> >>e0000001.voc clip on HQ mode >>e0000001.rhq raw HQ (80 bit block) data (no encapsulation) > > > After extensive googling, I've found only one standard speech codec > with these characteristics, and it is G.729 CELP. I cannot, however, > find any software that I can just download and experiment with. Could > someone who does have such software run the raw data above through it, > and tell me if it decodes?You can download a 'free for development' G.729 codec here: http://www.vovida.org/applications/downloads/G729A/> Email address in header is invalid. I am really > markus(AT)pinetree(DOT)org > > Markus-- Phil Frisbie, Jr. Hawk Software http://www.hawksoft.com