When Stem Creator will be upgraded? Bitrate of the stem file is 256kpbs max since 7years

2

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  • Kubrak
    Kubrak Member Posts: 2,789 Expert
    https://community.native-instruments.com/discussion/9966/stem-format-for-self-assemble

    I meant this thread. The guy managed to make 512kbitrate aac NI STEM.

  • Ninesense
    Ninesense Member Posts: 70 Helper

    This has been a struggle since the beggining of Stems and the issue is NI doesn't do much about it.

    Interestingly enough as a Mac user I now have to make the Stem files using ALAC but on a windows machine, and then play it on my Mac because the stem creator tool isn't working on a updated Mac.

  • Wades
    Wades Member Posts: 22 Member

    Up,

    @Allan_NI @Mark_NI @Kaiwan_NI Could someone from the NI team reply to us at least please?

    Even if the reply is not the solution but please let us know you hear us. And could you bring up this problem to the person concerned please?

    This problem is known since 2015 when stem concept was released..

  • Aquadics
    Aquadics Member Posts: 59 Helper

    I do not think that there is anything happening related to stems anymore. In maybe 3 - 4 month with the release of real time AI Stems in Traktor Pro 4, Stems based on tracks will not be a topic anymore for NI.

    I see this sad since for DJ's / Producer creating there own Stemps this will not be a good replacement.

  • Kubrak
    Kubrak Member Posts: 2,789 Expert

    Does Demucs or any other program make Traktor STEMs from stem files that user provides? And not using ALAC so that it may be ysed on Win....

  • valnum
    valnum Member Posts: 6 Member

    Hello all,

    I have started using the demucs free Python library a couple of months ago. So much pleasure. However it is a heavy piece of software and consumes a lot of resources (I only own a 2012 version of a MacBook Air, running Linux Mint, without much RAM nor the best processor of that era).. but it works, I can split stems. The process takes a long time on my setup though.

    I have then focused on the stem creation process. Having downloaded the software, I analyzed the MacOS version. It appears to be a script (not a compiled executable), based on a deprecated version of Python and an alternative version of ffmpeg (one of the best software I know to combine/convert audio or video data). What does that mean ? It means that the script can be analyzed, and adapted to up-to-date versions of these components: ffmpeg, and Python 3.

    I have extracted the stems of a song via demucs, and managed to generate a functional stem with ffmpeg. I have not tried to generate high quality versions of stems though.

    I'll try to find time to share something which you could use.

    The MP4 is a container: you can put FLAC-encoded sound if you want, as well as high bitrate lossy format to limit the loss of sound quality. The software reading the container (Traktor pro here) is the only limiting factor limit here. Traktor can handle FLAC individually, so handling 4 of them from a Stem is technically possible, and is only impossible because the software is still unable to do it.

    These are a couple of comments after reading your thread; if you want some more input from me feel free to ask more questions.

    Regards


    Valentin

  • valnum
    valnum Member Posts: 6 Member

    I have had a look into the Stem SDK contained in the ZIP file downloaded from the Stem website.

    In it you can find a script which you can run in a terminal. Terminal, if you don't know, is a text-based way to run programs, without graphical User Interface.

    The good news here is that the script is based on 2 wide-spread (despite outdated) software components:

    • AVCONV (better replaced by FFMPEG, the ultimate way to convert and put into containers audio and video data)
    • Python 2.7 (now replaced by Python 3)

    Both of them are free software (thank you open source).

    Python is only necessary to handle the complexity of the Stem creation:

    • format specification,
    • reading of a parameter file (in the JSON format),
    • file format conversion if not in supported formats,
    • error if target file format not supported, etc.

    I have analyzed the script and it only calls the AVCONV utility program to convert the audio files to AAC most of the time, with the 256k bitrate (which you already know).

    If you want to make a test, provided you have the mixed file and 4 separated tracks, and are familiar with the FFMPEG program and the terminal (or ask a geek 😜), you can run the following command in your terminal (you can guess what was the file I used for the test):

    ffmpeg -i Daft\ Punk\ -\ Something\ About\ Us.flac -i drums.flac -i bass.flac -i bass.flac -i other.flac -i vocals.flac -c:a aac -map 0:0 -map 1 -map 2 -map 3 -map 4 Daft\ Punk\ -\ Something\ About\ Us.stem.mp4

    Explanation:

    • ffmpeg is the magical program with merges all audio files together
    • every input file must be preceded with the -i parameter
    • there are 5 files (therefore 5 -i sections): the "mixed"/final track, and 4 separated tracks
    • if the file names contain spaces, make sure they are "escaped" with the \ character -- or just remove/replace them in every file name before the operation
    • -c:a aac means ffmpeg will convert them into the AAC codec
    • the -map parameters ensure the tracks are not merged but are kept separated in the target file
    • the last part, after the -map parameters, is the target file name which will be produced at the end of the process. Here again, same instructions than above if the file name contains spaces

    DIY! It is easy and hopefully it will work.

    I did that on Linux, because my MacOS is outdated and my MacBook Air is 11 years old, so I only open it to run Traktor and Ableton.


    To overcome the sound quality issue, you can try to add a parameter in the ffmpeg command to force a high bitrate conversion. Just add -b:a 512K right after the -c:a aac section to have a 512kbps bitrate instead of the 256k one.

    Since the Stem file is only a container of 5 audio files, and since Traktor is compatible with the FLAC codec, we could expect that we could encode the audio data in the FLAC format instead of the AAC one inside the container. However the Traktor Pro software can handle individual FLAC files, but could possibly not support a container of them.

    If you want to try to generate Stem files with FLAC encoded files, just replace the -c:a aac part with the -c:a flac string (don't add a bitrate parameter here).

    For the brave ones, please try to generate such files and tell us if the Traktor software can play them. And let me know if you need more assistance in these operations.

    Cheers!

    Valentin

  • Kubrak
    Kubrak Member Posts: 2,789 Expert

    Thanks, it seems easy.

    Would be great if flac would work, but I doubt it. But still, there is a hope.

  • Sûlherokhh
    Sûlherokhh Member, Traktor Mapping Mod Posts: 1,735 mod

    Awesome. Now all we need to do is set it all up and fiddle with the code. :)

  • valnum
    valnum Member Posts: 6 Member

    Hi guys,

    I have generated 3 stem files from the same song and its parts generated from demucs:

    • one file with aac codec and 256k bitrate
    • one file with aac codec and 512k bitrate
    • one file with flac content

    The whole is available at the link below. It is available until 100 downloads or 5 days then it vanishes. Could you have a try on them and tell which one(s) work and which don't? Hopefully at least one or 2 of them work.

    Here is the link:

    https://drop.chapril.org/download/6cc1d40a584657a9/#VScwFEGYRBPfTGnMHvb5CQ

  • Sûlherokhh
    Sûlherokhh Member, Traktor Mapping Mod Posts: 1,735 mod
    https://community.native-instruments.com/discussion/comment/55153#Comment_55153

    The FLAC doesn't play at all, the other two are recognized as a single mp3, not a STEM file.

  • valnum
    valnum Member Posts: 6 Member
    https://community.native-instruments.com/discussion/comment/55160#Comment_55160

    Thank you for your feedback. I'll work on it deeper to figure it out.

  • Sûlherokhh
    Sûlherokhh Member, Traktor Mapping Mod Posts: 1,735 mod

    I hope you will be able solve this. 🦋

  • Kubrak
    Kubrak Member Posts: 2,789 Expert

    I have the feeling some more info needs to be added to STEM file (maybe colours and settings for "mastering"). There was another thread by guy creating STEMs on Linux and he uploaded also sourcecode. Or you could ask him, what he did to make it get recognized as STEM file by Traktor.

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