Be-Music Translator (BMT)

Converts your BMS levels to a modern file format (osu, qua or json), ready to import & play.

This fork is used for my BMX2OSU converter. See it here.

How to Use

Output to Quaver: bmt.exe -i /path/to/input -o /path/to/output

Output to osu: bmt.exe -i /path/to/input -o /path/to/output -type osu

Get JSON info only: bmt.exe -i /path/to/input -o /path/to/output -json-only (see last section for details in info included)

Options

Option	Arguments?	Optional?	Description	Default
-i	Yes	No	Path of input folder containing folders of BMS charts.	N/A
-o	Yes	No	Path to output the converted files to.	N/A
-vol	Yes	Yes	Volume of hit sounds. (0-100)	100
-type	Yes	Yes	Which type of file to convert to. You can choose quaver or osu.	quaver
-hp	Yes	Yes	osu! only. Specify the HP drain rate. (0.0-10.0)	8.5
-od	Yes	Yes	osu! only. Specify the overall difficulty. (0.0-10.0)	8.0
-v	No	Yes	If this is specified, all logs (including some debug information) will be shown. Useful if you want to know why some maps didn't convert.	N/A
-auto-scratch	No	Yes	If this is specified, all notes in the scratch lane will be replaced with sound effects instead, and the scratch lane will not be shown in all clients.
-keep-subtitles	No	Yes	If this is specified, implicit subtitles will not be removed from song titles.	N/A
-no-storyboard	No	Yes	osu! only. If this is specified, background animation frames won't be parsed or inserted into the output files.	N/A
-no-measure-lines	No	Yes	If this is specified, timing points will not be added at the end of each track to create visible measure lines. (It's a cosmetic thing and doesn't affect gameplay, but it might make slowjam unreadable. Some BMS files' notes will appear unsnapped if this is enabled.)	N/A
-no-timing-points	No	Yes	If this is specified, no timing points will be added to the output file. This means no SV changes and is useful for SV maps which don't convert correctly.	N/A
-json	No	Yes	In addition to the output, an accompanying .json file will be created for each chart, with information about the file (start times, metadata, etc). These will be placed in the same output folder.	N/A
-json-only	No	Yes	When specified, no zips will be created, only .json files. -json becomes irrelevant if you enable this.	N/A

Limitations

• #IF 1 will always be used. All other #IF blocks will be ignored. If an #IF N block where n is not 1 is never terminated with #ENDIF, the rest of the track will not be read.
• #SWITCH blocks can't be parsed (yet). If people want this i'll add it in.
• Almost no BMS maps use long notes in channels 51-59, they use #LNOBJ. As a result, LNs placed in channels 51-59 are untested, but they are implemented. If you find a problem with them, please open an issue.
• BMS maps that use images as frames for the Background Animation can't be reliably parsed if the frames are <1ms apart, since osu! requires truncation of the decimal.
• If a BPM change occurs at any point within a STOP command, BMTranslator will still be able to parse the map, but the timing of the rest of the song will most likely be fucked. However, this has not appeared in a single map that I've tested, and by this reasoning, I think the only way to do this is by editing a BMS file by hand.

Understanding the JSON output

• The hit_objects field has an array of hit objects, ordered by the lane they appear in (index 0 = lane 1...index 7 = lane 8)
• Each key_sounds field contains a sample value with an integer. If there is no key sound on that note, the sample value will always be 0. The sample value, minus 1, is the index of the file name that should play in reference to sample_index. For example, if the sample is 3, you would look at sound_effect_index[2] to figure out which file to play.
• end_time values in hit objects will always be 0 unless is_long_note is true.

Credits

This tool wouldn't be possible without help from others. Thank you to:

• Swan for helping me with .qua files
• yahweh for moral support and for being a cool friend (and everyone in arrowsmashers)
• mat for helping me with the math side of things
• Jakads for helping with 0 BPM change in osu
• hitkey for their very helpful BMS notes/documentation. It is very thorough and an excellent reference for anyone looking to work with BMS and similar formats.
• Various people on the osu! forums who explained how timing points in osu! work.

License

MIT License. See the LICENSE file for more information.