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AudioPlayer: support stereo

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This commit is contained in:
Thomas Farstrike
2025-10-28 18:54:05 +01:00
parent f43684a2db
commit 1984857ada
1 changed files with 39 additions and 33 deletions
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internal_filesystem/apps/com.micropythonos.musicplayer/assets/audio_player.py
+39 -33
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@@ -5,17 +5,17 @@ import micropython
# ----------------------------------------------------------------------
# AudioPlayer – robust, volume-controllable WAV player
# AudioPlayer – robust, volume-controllable WAV player (MONO + STEREO)
# ----------------------------------------------------------------------
class AudioPlayer:
# class-level defaults (shared by every instance)
_i2s = None # the I2S object (created once per playback)
_volume = 50 # 0-100 (100 = full scale)
# class-level defaults
_i2s = None
_volume = 50 # 0-100
_keep_running = True
@staticmethod
def find_data_chunk(f):
"""Skip chunks until 'data' is found → (data_start, data_size, sample_rate)"""
"""Skip chunks until 'data' is found → (data_start, data_size, sample_rate, channels)"""
f.seek(0)
if f.read(4) != b'RIFF':
raise ValueError("Not a RIFF file")
@@ -25,6 +25,7 @@ class AudioPlayer:
pos = 12
sample_rate = None
channels = None
while pos < file_size:
f.seek(pos)
chunk_id = f.read(4)
@@ -38,14 +39,13 @@ class AudioPlayer:
if int.from_bytes(fmt[0:2], 'little') != 1:
raise ValueError("Only PCM supported")
channels = int.from_bytes(fmt[2:4], 'little')
if channels != 1:
raise ValueError("Only mono supported")
if channels not in (1, 2):
raise ValueError("Only mono or stereo supported")
sample_rate = int.from_bytes(fmt[4:8], 'little')
if int.from_bytes(fmt[14:16], 'little') != 16:
raise ValueError("Only 16-bit supported")
elif chunk_id == b'data':
return f.tell(), chunk_size, sample_rate
# next chunk (pad byte if odd length)
return f.tell(), chunk_size, sample_rate, channels
pos += 8 + chunk_size
if chunk_size % 2:
pos += 1
@@ -56,37 +56,35 @@ class AudioPlayer:
# ------------------------------------------------------------------
@classmethod
def set_volume(cls, volume: int):
"""Set playback volume 0-100 (100 = full scale)."""
volume = max(0, min(100, volume)) # clamp
volume = max(0, min(100, volume))
cls._volume = volume
@classmethod
def get_volume(cls) -> int:
"""Return current volume 0-100."""
return cls._volume
#@classmethod
def stop_playing():
@classmethod
def stop_playing(cls):
print("stop_playing()")
AudioPlayer._keep_running = False
cls._keep_running = False
@classmethod
def play_wav(cls, filename):
AudioPlayer._keep_running = True
"""Play a large mono 16-bit PCM WAV file with on-the-fly volume."""
cls._keep_running = True
try:
with open(filename, 'rb') as f:
st = os.stat(filename)
file_size = st[6]
print(f"File size: {file_size} bytes")
data_start, data_size, sample_rate = cls.find_data_chunk(f)
print(f"data chunk: {data_size} bytes @ {sample_rate} Hz")
data_start, data_size, sample_rate, channels = cls.find_data_chunk(f)
print(f"data chunk: {data_size} bytes @ {sample_rate} Hz, {channels}-channel")
if data_size > file_size - data_start:
data_size = file_size - data_start
# ---- I2S init ------------------------------------------------
i2s_format = machine.I2S.MONO if channels == 1 else machine.I2S.STEREO
try:
cls._i2s = machine.I2S(
0,
@@ -95,18 +93,19 @@ class AudioPlayer:
sd =machine.Pin(16, machine.Pin.OUT),
mode=machine.I2S.TX,
bits=16,
format=machine.I2S.MONO,
format=i2s_format,
rate=sample_rate,
ibuf=32000
)
except Exception as e:
print(f"Warning: simulating playback due to error initializing I2S audio device: {e}")
print(f"Warning: simulating playback (I2S init failed): {e}")
print(f"Playing {data_size} bytes (vol {cls._volume}%) …")
f.seek(data_start)
@micropython.viper
def scale_audio(buf: ptr8, num_bytes: int, scale_fixed: int):
# Process 16-bit samples (2 bytes each)
for i in range(0, num_bytes, 2):
lo = int(buf[i])
hi = int(buf[i+1])
@@ -121,32 +120,39 @@ class AudioPlayer:
buf[i] = sample & 255
buf[i+1] = (sample >> 8) & 255
chunk_size = 4096 # 4 KB → safe on ESP32
chunk_size = 4096
bytes_per_sample = 2 * channels # 2 bytes per channel
total = 0
while total < data_size:
# Progress:
#if total % 51 == 0:
# print('.', end='')
if not AudioPlayer._keep_running:
print("_keep_running = False, stopping...")
if not cls._keep_running:
print("Playback stopped by user.")
break
to_read = min(chunk_size, data_size - total)
raw = bytearray(f.read(to_read)) # mutable for in-place scaling
# Ensure we read full samples
to_read -= (to_read % bytes_per_sample)
if to_read <= 0:
break
raw = bytearray(f.read(to_read))
if not raw:
break
# ---- fast viper scaling (in-place) ----
scale = cls._volume / 100.0 # adjust the volume on the fly instead of at the start of playback
# Apply volume scaling (in-place, per sample)
scale = cls._volume / 100.0
if scale < 1.0:
scale_fixed = int(scale * 32768)
scale_audio(raw, len(raw), scale_fixed)
# ---------------------------------------
# Write to I2S (stereo interleaves L,R,L,R...)
if cls._i2s:
cls._i2s.write(raw)
else:
time.sleep((to_read/2)/44100) # 16 bits (2 bytes) per sample at 44100 samples/s
# Simulate timing
num_samples = len(raw) // bytes_per_sample
time.sleep(num_samples / sample_rate)
total += len(raw)
print("Playback finished.")