Re: [linux-minidisc] How to transfer ATRAC files without converting to WAV

[Thomas Perl <th.perl@gmail.com>]

Hi,

Don’t confuse ATRAC3 in a WAV container with the “uncompressed PCM” in a WAV container.

At least with "netmd/upload.py” in the repo, the original ATRAC-encoded audio data will be kept intact, SP (mono/stereo) tracks will be put into an .aea file, and LP2/LP4 aka ATRAC3 will be put into a .wav container — however, the audio in the wav will still be the ATRAC3-encoded data, so there’s no generational loss (you can check with “ffprobe” from ffmpeg or the “Codec Information” dialog in VLC). For this reason, the .aea and .wav files will only be playable by tools that support the ATRAC3 codecs (e.g. ffmpeg or VLC come to mind).

Alternatively, you can copy those tracks also with SonicStage, which IIRC will put them in an OMA container format, but that should also not do any conversion, but just contain the original audio data(?). Doesn’t hurt to store both variants in case one turns out to be better than the other (for archival purposes). SonicStage and the MZ-RH1 driver still work in 64-bit Windows 10, but it does need some hunting of the right files and unsigned driver installation, etc.. — but good enough for a one-off archival operation.

As far as I understand, for non-Hi-MD-formatted disks, there’s no real container/wrapper that can be transferred from the disk, but the data that you get in the .aea or .wav files is definitely as “bit-to-bit” as you can get with an MZ-RH1.

For Hi-MD formatted disks (ATRAC3plus: Hi-SP/Hi-LP/PCM), you can create a disk image of the filesystem or just copy the folder and then access the files via Hi-MD tools for preservation/archival (this worked at least for analog/microphone recordings done with an MZ-RH1, not sure if recordings from other Hi-MD recorders have any additional protection).

Once you have a bit-by-bit copy of the encoded ATRAC/3/3plus data, I’d still recommend storing an additional copy of those files in more broadly available formats (PCM WAV/FLAC/MP3) just so that the archived data is more easily accessible and does not rely on libhimd/ffmpeg for extracting/decoding the audio data (definitely store a copy of the source and binaries of all tools/codecs it needs with the ATRAC-encoded “original” data, as you will need those to access the data at all). And by converting it to FLAC once, there’s no generational loss, while still keeping it in a well-documented, widely-implemented format (I personally even went with MP3 for the “accessible” format and accepting generational loss, because it’s good enough and practical, and I also have an archival copy of the ATRAC-encoded audio should I ever feel the need to re-convert it).


HTH,
Thomas

> On 03.02.2021, at 22:51, Klavier Wong <klavier.wong5@gmail.com> wrote:
> 
> Hi all,
> 
> I am an audiovisual archivist working with MD collections. I successfully use NetMDPython and QHiMDTransfer GUI to transfer audio files from MD to PC (I am using a MAC). But after file transfer, the original audio files (no matter in LP2, LP4, Hi-SP, Hi-LP or PCM) will be automatically converted to .WAV format. As an archivist, I DON'T WANT the conversion. I hope to keep the files in their original codec and wrapper, such as the ATRACplus, ATRAC3 codecs. 
> 
> Could anyone give me some hints how I can achieve this? 
> 
> 
> 
> -- 
> Klavier J. Wang (Wong)
> Graduate candidate, Moving Image Archiving and Preservation (MIAP), New York University
> Ph.D. & M.Phil. (communication studies, HKBU, CUHK)  /  https://hk.linkedin.com/in/klavierwang8573
> 
> (2020) Hong Kong Popular Culture - Worlding Film, Television, and Pop Music https://www.palgrave.com/gp/book/9789811388163
> 
> 
> 
> 
> 
> 
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