The first tool of the opensnes-* family (The opensnes-* tools: conventions). It turns a PCM .wav — a jump, a hit, a UI blip, a voice clip — into the .brr the SNES DSP plays, plus a header with its sizes, and it tells you what a sample costs before you commit to it. The encoder is the one smconv bakes into soundbanks and the one wav2brr used: a .brr from here is byte for byte what wav2brr wrote.

Encode

opensnes-sample encode res/jump.wav                 # → res/jump.brr, res/jump.h
opensnes-sample encode res/hum.wav --loop 40 200    # loop between two sample indices
opensnes-sample encode res/*.wav --out build/       # several at once, elsewhere
opensnes-sample encode res/hum.wav --loop 40 200 --save   # remember the loop beside the file

In: PCM WAV, 8- or 16-bit, mono or stereo (stereo is downmixed). Keep the source at 32 kHz or below: the DSP plays BRR at 32 kHz whatever the file said, so a 44.1 kHz source comes out lower and slower (the tool warns and says by how much).

Out: jump.brr (raw BRR, one 9-byte block per 16 samples, loop and end flags set) and jump.h:

#define jump_brr_size 1035   /* bytes: 115 BRR blocks of 16 samples */
#define jump_brr_loop 0      /* byte offset of the loop point; 0 with no loop */
#define jump_brr_loops 0     /* 1 = the sample loops */
#define jump_tuning 4096     /* x4096: 4096 = plays at the pitch it was encoded at */
#define jump_rate 32000      /* Hz of the source; the DSP plays at 32000 */

A loop has to be a whole number of 16-sample blocks, because BRR is. When the one you give is not, the tool makes it so, in one of two ways:

it repeats the loop until the total is a multiple of 16, when that stays under 2,000 samples: a waveform of 8 samples becomes one block holding it twice, one of 12 samples becomes three blocks holding it four times. Nothing changes in pitch, and _tuning is 4096;
it resamples the loop to the next multiple of 16 otherwise. The sample then plays slightly lower, the tool warns, and _tuning (and "tuning_x4096" in --json) carries the factor: multiply the playback pitch by _tuning / 4096 to get the original pitch back.

A loop that does not start on a block boundary is preceded by silence so that it does. _brr_loop is the byte offset the loop comes back to; 0 means "from the start", not "no loop": _brr_loops says whether it loops.

Bake the .brr into the ROM and load it with the sizes from the header:

ASSET_SECTION "samples"
jump_brr:  .incbin "res/jump.brr"
.ENDS

#include "res/jump.h"
extern u8 jump_brr[];
audioLoadSample(0, jump_brr, jump_brr_size, jump_brr_loop);
audioPlaySample(0);

examples/audio/soundboard is the worked example, Audio & Music Tutorial the tutorial.

Settings beside the asset

--save writes res/hum.wav.toml next to the file:

tool = "opensnes-sample"
 
[encode]
loop = [40, 200]

From then on opensnes-sample encode res/hum.wav loops without being told, and a --loop on the command line overrides it for that run. The file is the one the build system reads (the tool line says which tool converts the asset); a key it does not know is refused, so a typo cannot fall back to a default in silence.

Inspect

opensnes-sample inspect res/jump.wav # 32000 Hz, 16-bit, mono, 1840 samples (0.058 s) -> 115 BRR blocks, 1035 bytes of ARAM

opensnes-sample inspect res/*.brr --json # one JSON object: bytes, blocks, loop, ARAM

Nothing is converted or written; this is how you size a sound set against the 64 KB of audio RAM before recording more.

Exit codes and messages

0 done; 1 the input was refused and the message names the limit (--loop 100 50 is out of range — the file has 220 samples, START < END); 2 usage; 3 the file system. A refused input writes nothing. --json puts the result — sources, outputs, blocks, ARAM bytes, loop — on stdout as one object; -q drops the summary line; -v says what is being done.

From wav2brr

wav2brr	opensnes-sample
wav2brr in.wav [out.brr]	opensnes-sample encode in.wav [--out DIR] (the name follows the input)
--loop START END	the same, and --save keeps it in in.wav.toml
-v prints the load line	in.h carries the sizes; inspect the figures

Same bytes: the golden suite of opensnes-sample compares its .brr against wav2brr's goldens.