Note that since the makebax release.zip only provides Windows binaries, these OSes will likely need some form of Wine in their instructions.
Might need troubleshooting info
makebax is a command-line utility for converting .IVF video files into .BAX animations to be used with BAX and played on a Nintendo 3DS.
Creating .BAX Animations
What You Need
The latest release of makebax (files vary depending on your OS)
The latest release of ffmpeg installed on your computer
Instructions
Section I - Installing ffmpeg and makebax
For FFmpeg:
On the ffmpeg website, click on the Windows icon and then the Windows builds by BtbN option
On that page, download the file whose name ends with win64-gpl.zip
Once it's downloaded, extract the file to a folder
Move the folder to any place of your choosing, but make sure to choose a place where you won't move it again
Once you have the folder in the correct place, enter the bin folder inside it. Then, click on the address bar and copy the file path that appears in its place
Open the Windows search bar and find the Control Panel
In the Control Panel, click on the search bar and type environment
Choose the option that says "Edit environment variables for your account"
In the window that opens, find the option named Path, click on it, and click Edit...
In the window that opens, click New, paste the file path you copied earlier, then press Enter and click OK
WIP
In a terminal window, use your system's package manager (such as apt, dnf or pacman) while sudo or root to install ffmpeg.
For makebax:
Download release.zip from the makebax releases page.
Extract the release.zip to a folder and move it to any location of your choice
WIP
WIP
Section II - Converting the video
Copy the video you wish to convert into the makebax folder
Inside that folder, hold SHIFT and right-click anywhere in the empty space - in the resulting menu, click the option that opens a terminal, Command Prompt, or PowerShell window
Use ffmpeg to transcode your desired video into IVF format
For example, if your video is a file named input.mp4, the command would be ffmpeg -i "input.mp4" -f ivf "converted.ivf"
The video must have a resolution of 400x240, 320x240, or 720x240. If it doesn't meet the requirements, instead do ffmpeg -i "input.mp4" -f ivf -vf scale=<WIDTH>:240,fps=<FRAMERATE> "converted.ivf" - <WIDTH> must be 400, 320 or 720 and <FRAMERATE> must be a number between 1 and 60.
Use makebax to convert your .IVF file to a .BAX file
When running the command, put the full filename of one of the makebax .EXEs (e.g. makebax-win64.exe) before the command.
If you named your converted video converted.ivf, the command would be <makebax EXE filename> "converted.ivf" "output.bax"
Copy output.bax to sdmc:/bax/ on your console's SD card
You have created a usable .BAX file. It will be played (chosen at random, if you already had a .BAX file before this) when your 3DS next boots.
Command Line Usage
Put the filename of either makebax .exe before the command, and make sure you're running this from inside the makebax release folder.
input.ivf is the input IVF file path, the size must have a resolution of either 400x240 (top screen only), 320x240 (bottom screen only) or 720x240 (both screens side-by-side). Input must be an IVF container with a VP8/VP9 stream.
output.bax is the path to the BAX file that will be created.
s sets the block size. n is the number of frames that are processed per iteration. The higher the number, the more memory is used on runtime (and the less often disk accesses are required). Defaults to 48.
c sets the compression level. Should be between 1 (lowest) and 16 (highest). Defaults to 6.
b sets the background color. bg_color should be the 16-bit integer representation of an RGB565 color. Defaults to zero (black). Refer to this site for more information.
a sets the Author string. It doesn't affect the player at all, but it's nice to include some metadata. Maximum length is 32 ASCII characters (or as much UTF-8 fits in there).
i is the same as above but for Information. Maximum length is 192 ASCII characters.
Notes
IVF is a simple container for VP8/VP9 streams, unable to contain more than one stream. It was chosen as the input format due to it being both simple and straightforward to work with.
Although it should be compatible with big endian platforms (PowerPC, Microblaze, etc) this has not been properly tested yet. Please report any issues regarding compilation/usage on big endian platforms.
While having libav* support would be ideal, it's less than fit due to it's programming complexity (easy to make mistakes with) and labyrinth of dependencies (requires X11 libs, so it's unusable from servers, f.e.).
For best performance, the block size should be an integer multiple of the number of available hardware threads (logical processors). This is why the default block size is 48: it's a multiple of the most common PO2 and MO6 multithread setups.
BAX files should not surpass the 32MiB mark. makebax doesn't enforce this limit, but BAX does.
