ROM Hack [TUTORIAL] - How to make a Multi-Stream (more than 1 pair of channels) BCSTM for 3DS Hacking

[Gaming796]

I've seen a lot of confusion going around the Internet on this topic, so here's a simple, precise Tutorial.

Note that in this Tutorial I'll be using Microsoft Windows OS. Please mind that few steps might not be the same on other OS like Macintosh OS X and you might need to download additional programs.

First of, a Multi-Stream BCSTM is a BCSTM with more than 1 Pair of Channels. It's usually 4ch (4 Channels), but can be 6ch (6 Channels) and Maximum 8ch (8 Channels). Games like Mario Kart 7 make use of such BCSTMs.

Here's what you'll need on your PC:
1. Python 2.7.0 (Download Here)
2. Smash 3DS Pack (it's a 7-Zip Archive - unzip using WinRAR / 7-Zip) (Download Smash 3DS Pack Here) (Download 7-Zip Here) (Download WinRAR Here)
3. Audacity (Download here)

Let's begin!
Install Python 2.7.0 and Audacity. Once done, unzip Smash 3DS Pack in a suitable location (I'd say your Desktop would be fine). Now open Smash 3DS Pack folder and navigate to Sound\Smash IDSP Build and right click > edit on the file named "sm4shidspbuild.bat". Now it should open up Notepad with some text written. Scroll till you reach the line where it says ":Smash". On the line right below this, the following text will be written:

revb --build-idsp "%~n1.idsp" !wdrevBuild!

Change that to the following:

revb --build-bcstm "%~n1.bcstm" !wdrevBuild!

Once done click on File > Save.

Now open the song file which you want to convert to a Multi-stream BCSTM in Audacity. Once you open it check whether the song is a Stereo Track or Mono Track. If it's mono, then just copy and paste the song one below the other (for 4ch, make 3 copies, for 6ch make 5 copies and for 8ch make 7 copies). If you wish to have different tracks of each stream then open the song via File > Import Audio (OR Ctrl+Shift+I) and make a copy of those as well. If your imported songs are stereo, just click on the arrow near the song name and click on Split Stereo track. Now you have 2 mono tracks for each stream. Once you have created all channels, just go to Edit > Preferences (OR Ctrl + P) and under Import / Export Section, select Use Custom Mix. Click on OK. Now on the bottom bar where the time is shown in hh:mm:ss:msmsms, click on the arrow and change it to Samples. Now huge numbers like 123,456,789 will be displayed. Find the loop points of the song and note them down. Go to File > Edit Metadata and make new labels called "LOOPSTART" and "LOOPLENGTH". Under these put the "Loop Start Sample" and "Loop End Sample" Numbers respectively. Now click on File > Export Audio (OR Ctrl + Shift + E) and save the file in the folder "Smash IDSP Build" as an OGG Vorbis File (.ogg). Once done, drag and drop your OGG Vorbis file onto the "sm4shidspbuild.bat" file. Let it do the rest of the job. Once done it should output your OGG Vorbis file with the same name but a .bcstm extension. You've done it - you created a Multi-Stream BCSTM!!!!

Hope this was helpful!