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fix: correct RIFF chunk sizes in SF3 converter

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- _find_chunk starts at offset 12 (after RIFF header)
- Add _find_list_of_type to locate sdta LIST
- Update sdta LIST size after smpl data replacement
- Fix 'Invalid chunk header' error in SpessaSynth
- SGM_v2.01 too large (529MB WAV) falls back to SF2
This commit is contained in:
3dtours
2026-07-26 18:29:05 +07:00
parent e843f55483
commit 72186168d2
1 changed files with 100 additions and 40 deletions
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app/core/soundfont_converter.py
+100 -40
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@@ -2,7 +2,6 @@ import os
import struct
import subprocess
import logging
import tempfile
import wave
logger = logging.getLogger(__name__)
@@ -12,18 +11,65 @@ SF_TARGET_DIRS = [
]
def _read_chunks(data, offset, max_size=0):
chunks = []
def _find_chunk(data, chunk_id, offset=12, max_size=0):
pos = offset
end = len(data) if max_size == 0 else offset + max_size
while pos + 8 <= end:
ck_id = data[pos:pos + 4]
ck_size = struct.unpack("<I", data[pos + 4:pos + 8])[0]
chunks.append((ck_id, pos + 8, ck_size, pos))
if ck_id == chunk_id:
return (pos, ck_id, ck_size, pos + 8)
if ck_id == b"LIST" and pos + 12 <= end:
list_type = data[pos + 8:pos + 12]
# Check if we're looking for a specific list type
if chunk_id == b"smpl" and list_type == b"sdta":
inner = _find_chunk_in_list(data, chunk_id, pos + 12, ck_size - 4)
if inner:
return inner
elif chunk_id == b"LIST":
# When searching for LIST by type, check if it's sdta
pass
else:
inner = _find_chunk_in_list(data, chunk_id, pos + 12, ck_size - 4)
if inner:
return inner
pos += 8 + ck_size
if ck_size % 2 == 1:
pos += 1
return chunks
return None
def _find_list_of_type(data, list_type_id, offset=12):
pos = offset
while pos + 12 <= len(data):
ck_id = data[pos:pos + 4]
ck_size = struct.unpack("<I", data[pos + 4:pos + 8])[0]
if ck_id == b"LIST":
form_type = data[pos + 8:pos + 12]
if form_type == list_type_id:
return (pos, ck_id, ck_size, pos + 12)
pos += 8 + ck_size
if ck_size % 2 == 1:
pos += 1
return None
def _find_chunk_in_list(data, chunk_id, list_data_offset, list_data_size):
pos = list_data_offset
end = list_data_offset + list_data_size
while pos + 8 <= end:
ck_id = data[pos:pos + 4]
ck_size = struct.unpack("<I", data[pos + 4:pos + 8])[0]
if ck_id == chunk_id:
return (pos, ck_id, ck_size, pos + 8)
pos += 8 + ck_size
if ck_size % 2 == 1:
pos += 1
return None
def _update_size(data, offset, new_size):
return data[:offset] + struct.pack("<I", new_size) + data[offset + 4:]
class SoundFontConverter:
@@ -51,38 +97,35 @@ class SoundFontConverter:
return False
if len(data) < 12 or data[:4] != b"RIFF" or data[8:12] != b"sfbk":
logger.warning("Not a valid SF2 file")
return False
top_chunks = _read_chunks(data, 12)
smpl_data = None
smpl_offset = 0
smpl_size = 0
# Find smpl chunk recursively
smpl = _find_chunk(data, b"smpl")
if smpl is None:
logger.warning("No smpl chunk found in SF2")
return False
for ck_id, ck_data_off, ck_size, ck_head_off in top_chunks:
if ck_id == b"LIST":
list_type = data[ck_data_off:ck_data_off + 4]
inner_chunks = _read_chunks(data, ck_data_off + 4, ck_size - 4)
for ic_id, ic_data_off, ic_size, ic_head_off in inner_chunks:
if ic_id == b"smpl":
smpl_data = data[ic_data_off:ic_data_off + ic_size]
smpl_offset = ic_data_off
smpl_size = ic_size
smpl_head_off, _, smpl_old_size, smpl_data_off = smpl
sample_data = data[smpl_data_off:smpl_data_off + smpl_old_size]
if smpl_data is None or smpl_size < 16:
logger.warning("No sample data found in SF2")
if len(sample_data) < 16:
logger.warning("Sample data too small")
return False
tmp_wav = sf3_path + ".tmp.wav"
tmp_ogg = sf3_path + ".tmp.ogg"
try:
# Write samples as WAV
with open(tmp_wav, "wb") as fw:
with wave.open(fw, "wb") as w:
w.setnchannels(1)
w.setsampwidth(2)
w.setframerate(44100)
w.writeframes(smpl_data)
w.writeframes(sample_data)
# Compress to Ogg Vorbis
subprocess.run([
"ffmpeg", "-y", "-i", tmp_wav,
"-c:a", "libvorbis", "-q:a", "3",
@@ -92,41 +135,60 @@ class SoundFontConverter:
with open(tmp_ogg, "rb") as fo:
ogg_data = fo.read()
compression = (1 - len(ogg_data) / max(len(smpl_data), 1)) * 100
logger.info(f"Compressed {len(smpl_data)} -> {len(ogg_data)} bytes ({compression:.0f}%)")
compression = (1 - len(ogg_data) / max(len(sample_data), 1)) * 100
logger.info(f"Compressed {len(sample_data)} -> {len(ogg_data)} bytes ({compression:.0f}%)")
# Rebuild file: replace smpl chunk data with Ogg data
ogg_padded = ogg_data if len(ogg_data) % 2 == 0 else ogg_data + b"\x00"
new_smpl_size = len(ogg_data)
old_padded = smpl_old_size + (1 if smpl_old_size % 2 == 1 else 0)
new_padded = len(ogg_padded)
delta = new_padded - old_padded
# Rebuild file: replace smpl chunk and update all sizes
out = bytearray()
out.extend(data[:smpl_offset - 8]) # up to smpl chunk header
out.extend(data[:smpl_head_off]) # up to smpl chunk header
out.extend(struct.pack("<I", new_smpl_size)) # new smpl size
out.extend(ogg_padded) # Ogg data (padded)
smpl_end = smpl_offset + smpl_size
padded_smpl_end = smpl_end + (1 if smpl_size % 2 == 1 else 0)
out.extend(data[padded_smpl_end:]) # rest of file
out.extend(ogg_padded) # compressed data (even-padded)
out.extend(data[smpl_head_off + 8 + old_padded:]) # rest of file
# Fix RIFF size
old_total = struct.unpack("<I", data[4:8])[0]
size_diff = len(out) - 8 - old_total
new_size = old_total + size_diff
out[4:8] = struct.pack("<I", new_size)
data_out = bytes(out)
# Find sdta LIST and update its size
sdta = _find_list_of_type(data_out, b"sdta", 12)
if sdta:
lh_off, _, lh_size, ld_off = sdta
data_out = _update_size(data_out, lh_off + 4, lh_size + delta)
# Update RIFF root size
old_riff_size = struct.unpack("<I", data_out[4:8])[0]
new_total = len(data_out) - 8
data_out = _update_size(data_out, 4, new_total)
with open(sf3_path, "wb") as fout:
fout.write(bytes(out))
fout.write(bytes(data_out))
# Validate: check that RIFF size matches actual size
written = os.path.getsize(sf3_path)
parsed_riff = struct.unpack("<I", data_out[4:8])[0]
if parsed_riff != written - 8:
logger.warning(f"Size mismatch: RIFF says {parsed_riff}, actual is {written - 8}")
return False
return True
return os.path.exists(sf3_path)
except subprocess.TimeoutExpired:
logger.error("Ogg conversion timed out")
return False
except Exception as e:
logger.error(f"Conversion error: {e}")
import traceback
traceback.print_exc()
return False
finally:
for p in [tmp_wav, tmp_ogg]:
try:
if os.path.exists(p): os.remove(p)
if os.path.exists(p):
os.remove(p)
except Exception:
pass
@@ -154,7 +216,6 @@ class SoundFontConverter:
try:
logger.info(f"Converting '{sf2_path}' -> '{sf3_path}' using {converter}...")
if converter == "fluidsynth":
logger.warning("fluidsynth CLI does not export SF3, using Python converter")
converter = "python"
if converter == "mscore":
@@ -163,7 +224,6 @@ class SoundFontConverter:
if result.returncode == 0 and os.path.exists(sf3_path):
logger.info(f"Created SF3 via mscore: {sf3_path} ({os.path.getsize(sf3_path)/1024/1024:.1f}MB)")
return sf3_path
logger.warning(f"mscore failed, trying Python converter")
converter = "python"
if converter == "python":
@@ -171,7 +231,7 @@ class SoundFontConverter:
size_mb = os.path.getsize(sf3_path) / (1024 * 1024)
logger.info(f"Created SF3: {sf3_path} ({size_mb:.2f} MB)")
return sf3_path
logger.warning(f"Python converter failed, returning SF2 path")
logger.warning(f"Python converter failed for {sf2_path}, returning SF2 path")
return sf2_path
return sf2_path