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@andrew-wilkes
Created September 2, 2022 04:43
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Audio File Parser
class_name Audio
var player: AudioStreamPlayer
var info
func _init(audio_player_instance):
player = audio_player_instance
func load_data(path: String):
var file = File.new()
var err = file.open(path, File.READ)
if err == OK:
var data = file.get_buffer(file.get_len())
file.close()
var stream
match path.get_extension():
"mp3":
parse_mp3(data)
stream = AudioStreamMP3.new()
"ogg":
parse_ogg(data)
stream = AudioStreamOGGVorbis.new()
stream.data = data
player.stream = stream
func pause(pause = true):
player.stream_paused = pause
func stop():
player.stop()
func seek(time):
player.seek(time)
func set_volume(percent):
player.volume_db = clamp(percent - 1.0, 0, 1) * 30
func set_speed(target, actual): # e.g. 45, 33 RPM
player.pitch_scale = actual / target
func parse_ogg(data: PoolByteArray):
info = { error = null }
# Locate the comments header, it is where the second "vorbis" octet stream occurs
var hex = data.subarray(0, 0x100).hex_encode()
var idx = hex.find("766f72626973")
if idx > 0:
idx = hex.find("766f72626973", idx + 6) / 2 + 6
# Let's just use the 1st byte of the 32-bit length values for the length
# Skip over vendor_string
idx += data[idx] + 4
var num_comments = data[idx]
idx += 4
for n in num_comments:
var comment_length = data[idx]
idx += 4
var comment = data.subarray(idx, idx + comment_length - 1).get_string_from_utf8()
var tag_val = comment.split("=")
if tag_val.size() == 2:
var tag = tag_val[0].to_lower()
match tag:
"artist":
info["band"] = tag_val[1]
_:
info[tag] = tag_val[1]
idx += comment_length
func parse_mp3(data: PoolByteArray):
info = { error = null }
if data.size() < 10:
info.error = "NOT ID3"
return
# Detect ID3v2 tag
var header = data.subarray(0, 9)
var id = header.subarray(0, 2).get_string_from_ascii()
if id != "ID3":
info.error = "NOT ID3"
return
info["version"] = "ID3v2.%d.%d" % [header[3], header[4]]
var flags = header[5]
var _unsync = flags & 0x80 > 0
var extended = flags & 0x40 > 0
var _experimental = flags & 0x20 > 0
var _has_footer = flags & 0x10 > 0
var idx = 10
var end = idx + bytes_to_int(header.subarray(6, 9))
if extended:
idx += bytes_to_int(data.subarray(idx, idx + 3))
# Now idx points to the start of the first frame
while idx < end:
var frame_id = data.subarray(idx, idx + 3).get_string_from_ascii()
var size = bytes_to_int(data.subarray(idx + 4, idx + 7), frame_id != "APIC")
idx += 10
match frame_id:
"TIT2":
info["title"] = get_string_from_data(data, idx, size)
"TALB":
info["album"] = get_string_from_data(data, idx, size)
"COMM":
info["comments"] = get_string_from_data(data, idx, size)
"TYER":
info["year"] = get_string_from_data(data, idx, size)
"TPE1", "TPE2", "TPE3", "TPE4":
info["band"] = get_string_from_data(data, idx, size)
"TLEN":
info["length"] = get_string_from_data(data, idx, size)
"APIC":
# size of APIC does not use syncsafe number
# Ignore the encoding byte
# The image is always jpeg I think, but the mime-type text varies
# Could just detect the byte signature for verification ffd8 ... ffd9
var pic_frame = data.subarray(idx + 1, idx + size - 1)
var zero1 = pic_frame.find(0)
if zero1 > 0:
info["mime_type"] = pic_frame.subarray(0, zero1 - 1).get_string_from_ascii()
zero1 += 1 # Picture type
if zero1 < pic_frame.size():
zero1 += 1
if zero1 < pic_frame.size():
var zero2 = pic_frame.find(0, zero1)
info["description"] = get_string_from_ucs2(pic_frame.subarray(zero1, zero2 - 1))
info["image"] = pic_frame.subarray(zero2 + 1, -1)
"""
var img = Image.new()
match info["mime_type"]:
"image/jpg", "image/jpeg", "image/JPG":
var e = img.load_jpg_from_buffer(info["image"])
if e == OK:
img.save_png("res://temp.png")
"""
idx += size
func get_string_from_data(data, idx, size):
if size > 3 and Array(data.subarray(idx, idx + 2)).hash() == [1, 0xff, 0xfe].hash():
# Null-terminated string of ucs2 chars
return get_string_from_ucs2(data.subarray(idx + 3, idx + size - 1))
if data[idx] == 0:
# Simple utf8 string
return data.subarray(idx + 1, idx + size - 1).get_string_from_utf8()
# Syncsafe uses 0x80 multiplier otherwise use 0x100 multiplier
func bytes_to_int(bytes: Array, is_syncsafe = true):
var mult = 0x80 if is_syncsafe else 0x100
var n = 0
for byte in bytes:
n *= mult
n += byte
return n
func get_string_from_ucs2(bytes: Array):
var s = ""
var idx = 0
while idx < (bytes.size() - 1):
s += char(bytes[idx] + 256 * bytes[idx + 1])
idx += 2
return s
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