Add sound/spustream example

1 files changed, 112 insertions, 0 deletions

diff --git a/examples/sound/spustream/convert_stream.py b/examples/sound/spustream/convert_stream.py
new file mode 100644
index 0000000..1b1696f
--- /dev/null
+++ b/examples/sound/spustream/convert_stream.py
@@ -0,0 +1,112 @@
+#!/usr/bin/env python3
+# Simple .VAG to STREAM.BIN interleaving tool
+# (C) 2021 spicyjpeg - MPL licensed
+
+import sys
+from warnings  import warn
+from struct    import Struct
+from itertools import zip_longest
+from argparse  import ArgumentParser, FileType
+
+VAG_HEADER  = Struct("> 4s I 4x 2I 12x 16s")
+VAG_MAGIC   = b"VAGp"
+SAMPLE_RATE = 44100
+BUFFER_SIZE = 26624 # (26624 / 16 * 28) / 44100 = 1.05 seconds
+ALIGN_SIZE  = 2048
+
+## Helpers
+
+def align(data, size):
+	chunks = (len(data) + size - 1) // size
+
+	return data.ljust(chunks * size, b"\x00")
+
+def set_loop_flag(data):
+	last_block    = bytearray(data[-16:])
+	last_block[1] = 0x03 # Jump to loop point + sustain
+
+	return data[:-16] + last_block
+
+## .VAG file reader
+
+def read_vag(_file, chunk_size):
+	with _file:
+		header = _file.read(VAG_HEADER.size)
+		(
+			magic,
+			version,
+			size,
+			sample_rate,
+			name
+		) = VAG_HEADER.unpack(header)
+
+		#if magic != VAG_MAGIC:
+			#raise RuntimeError(f"{_file.name} is not a valid .VAG file")
+		if sample_rate != SAMPLE_RATE:
+			warn(RuntimeWarning(f"{_file.name} sample rate is not {SAMPLE_RATE} Hz"))
+
+		for i in range(0, size, chunk_size):
+			chunk   = _file.read(chunk_size)
+
+			if len(chunk) % 16:
+				warn(RuntimeWarning(f"{_file.name} is not 16-byte aligned, trimming"))
+				chunk = chunk[0:len(chunk) // 16 * 16]
+
+			chunk = set_loop_flag(chunk)
+
+			yield chunk.ljust(chunk_size, b"\x00")
+
+## Main
+
+def get_args():
+	parser = ArgumentParser(
+		description = "Generates interleaved stream data from one or more .VAG files."
+	)
+	parser.add_argument(
+		"input_file",
+		nargs = "+",
+		type  = FileType("rb"),
+		help  = f"mono input files for each channel (must be {SAMPLE_RATE} Hz .VAG)"
+	)
+	parser.add_argument(
+		"-o", "--output",
+		type    = FileType("wb"),
+		default = "stream.bin",
+		help    = "where to output converted stream data (stream.bin by default)",
+		metavar = "file"
+	)
+	parser.add_argument(
+		"-b", "--buffer-size",
+		type    = int,
+		default = BUFFER_SIZE,
+		help    = f"size of each interleaved chunk (one per channel, default {BUFFER_SIZE})",
+		metavar = "bytes"
+	)
+	parser.add_argument(
+		"-a", "--align",
+		type    = int,
+		default = ALIGN_SIZE,
+		help    = f"align each group of chunks to N bytes (default {ALIGN_SIZE})",
+		metavar = "bytes"
+	)
+
+	return parser.parse_args()
+
+def main():
+	args = get_args()
+	if args.buffer_size % 16:
+		raise ValueError("buffer size must be a multiple of 16 bytes")
+
+	interleave = zip_longest(
+		*( read_vag(_file, args.buffer_size) for _file in args.input_file ),
+		fillvalue = b"\x00" * args.buffer_size
+	)
+
+	with args.output as _file:
+		for chunks in interleave:
+			data = b"".join(chunks)
+
+			_file.write(align(data, args.align))
+
+if __name__ == "__main__":
+	main()