We have a Olympus VN-7800 that we need to recover deleted recordings from. We went down the avenue of a Chip-Off recovery and obtained a full binary dump of the 4GB BGA169 chip.
Looking at the data in Hex, 90% of the chip is zeros which isn't good to start with. There are unusual filetypes in four folders on a FAT32 partition.
A portion of the folder structure is
RECORDER\
RECORDER\FOLDER_A\
RECORDER\FOLDER_A\INDEX.DAT
RECORDER\FOLDER_A\VOC_110101-0004.AAE
RECORDER\FOLDER_A\VOC_110103-0008.AAI
RECORDER\FOLDER_A\VOC_110104-0009.AAJ
RECORDER\FOLDER_A\VOC_110106-0016.AAQ
RECORDER\FOLDER_A\VOC_110110-0018.AAS
RECORDER\FOLDER_A\VOC_110111-0019.AAT
RECORDER\FOLDER_A\VOC_110113-0020.AAU
We have tried to load some of these files into Audacity as raw data but none of these files play and are simply noise. The filetypes seem to be random (or incrementally generated) too, so is there any help or advice anyone can give with this?
We need to be able to play the files from the dump but this is the part we are having trouble with.
It seemingly uses
Sub Band Codec / CELP
https://
i.e. possibly this
https://
would do. ?
jaclaz
Thanks Jaclaz, I did read about that, I shall see what I can get )
Hello,
Can you share what is stored in the Index.dat file please? That might shed light on the other listed files.
If you can extract out the files named "VOC_110101-0004.AAE" etc., perhaps changing the extracted file extension(s) to .mpg or .wav or any of the other audio file extensions listed here will then allow you to open the audio files https://
Hello,
Can you share what is stored in the Index.dat file please? That might shed light on the other listed files.
If you can extract out the files named "VOC_110101-0004.AAE" etc., perhaps changing the extracted file extension(s) to .mpg or .wav or any of the other audio file extensions listed here will then allow you to open the audio files https://
en.wikipedia.org/wiki/Audio_file_format
Most probably the index.dat is nothing but a list of the files (in the "right" order), but no, if the thingy actually uses CELP, the issue is with the specific codec (which is specifically designed for speech compression) and that is unlikely to be present on a system/outside a specific program.
Moreover it seems like there are both "narrowband" and "wideband" versions of the encoding, so the speexdec.exe (windows) from 1.2beta3 should actually be the easier thing to try
https://
The problem might be that Olympus may use a slightly different version of the CELP codec. (
jaclaz
Thanks UnallocatedClusters and Jaclaz,
There are 4 main folders "A", "B", "C" and "D" all the DAT files are fully Zeros, so this doesn't help much.
Editing the File Extension was unsuccessul, I tried a lot including MPG, AAC, MP3, FITS, VOX, WMA among others. The files wouldn't render.
I thought WMA would perhaps do the trick because in the documentation on the Olympus site, it does mention WMA as one of its playback modes.
I can't seem to get the Speex exe to work, it simply flashes a command prompt window for a moment, are you implying Jaclaz that if Olympus may use their own variation of the CELP codec that it might not be something we can work around?
I'm going to have a dig at the CELP information and see if I can come up with any ideas about this, thank you two for both of your CELP … I mean help so far!
I can't seem to get the Speex exe to work, it simply flashes a command prompt window for a moment,
Are you joking? ?
It is a command line program, are you by any chance double clicking on it (and expect a GUI tool)? 😯
You open a command prompt and run the program in it, testing the various command line switches/parameters. (and you want to run speexdec.exe
C\appoggio\Speex\bin>speexdec
Usage speexdec [options] input_file.spx [output_file]
Decodes a Speex file and produce a WAV file or raw file
input_file can be
filename.spx regular Speex file
- stdin
output_file can be
filename.wav Wav file
filename.* Raw PCM file (any extension other that .wav)
- stdout
(nothing) Will be played to soundcard
Options
--enh Enable perceptual enhancement (default)
--no-enh Disable perceptual enhancement
--force-nb Force decoding in narrowband
--force-wb Force decoding in wideband
--force-uwb Force decoding in ultra-wideband
--mono Force decoding in mono
--stereo Force decoding in stereo
--rate n Force decoding at sampling rate n Hz
--packet-loss n Simulate n % random packet loss
-V Verbose mode (show bit-rate)
-h, --help This help
-v, --version Version information
--pf Deprecated, use --enh instead
--no-pf Deprecated, use --no-enh instead
More information is available from the Speex site http//
Please report bugs to the mailing list `speex-dev@xiph.org'.
jaclaz
Well that was a brain dead moment for me, the only other time I've really dealt with command line stuff is ADB Fasboot commands lol
Because the Speexdec exe is only after Speex files to convert, it says it can't handle the filetypes I'm trying to point it towards. I might look more into similarities between the files, I couldn't earlier determine the header to any filetype "PLSBÀ" is the start of each sector (50 4C 53 42 C0).
The CELP compression is rather complex, so it is entirely possible that one implementation is different from another.
Try this one
https://
It is for the Philips CELP, but maybe it is the same the Olympus use?
You can also try the guys that make the Express Scribe software
http//
and ask them if they know their software is compatible with the Olympus internal format, they do mention - for the Pro version - "Philips, Grundig, Olympus digital recorder formats", and the software is only a few tens of bucks, but asking them before buying a license is advised, it is possible that when connected to the PC the Olympus recorder does some kind of transformations to the files.
You can also try this one
http//
(an older version of the Olympus player, it may work with the newer devices or it may not)
http//
http//
jaclaz