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Commitd3be0ce

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AudioPlayer: upscale if low frequency
1 parent1984857 commitd3be0ce

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1 file changed

+70
-22
lines changed
  • internal_filesystem/apps/com.micropythonos.musicplayer/assets

1 file changed

+70
-22
lines changed

‎internal_filesystem/apps/com.micropythonos.musicplayer/assets/audio_player.py‎

Lines changed: 70 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -6,16 +6,19 @@
66

77
# ----------------------------------------------------------------------
88
# AudioPlayer – robust, volume-controllable WAV player (MONO + STEREO)
9+
# Auto-up-samples any rate < 22050 Hz to 22050 Hz for MAX98357
910
# ----------------------------------------------------------------------
1011
classAudioPlayer:
11-
# class-level defaults
1212
_i2s=None
13-
_volume=50# 0-100
13+
_volume=50# 0-100
1414
_keep_running=True
1515

16+
# ------------------------------------------------------------------
17+
# WAV header parser
18+
# ------------------------------------------------------------------
1619
@staticmethod
1720
deffind_data_chunk(f):
18-
"""Skip chunks until 'data' is found → (data_start, data_size, sample_rate, channels)"""
21+
"""Return (data_start, data_size, sample_rate, channels)"""
1922
f.seek(0)
2023
iff.read(4)!=b'RIFF':
2124
raiseValueError("Not a RIFF file")
@@ -68,6 +71,34 @@ def stop_playing(cls):
6871
print("stop_playing()")
6972
cls._keep_running=False
7073

74+
# ------------------------------------------------------------------
75+
# Helper: up-sample a raw PCM buffer (zero-order-hold)
76+
# ------------------------------------------------------------------
77+
@staticmethod
78+
def_upsample_buffer(raw:bytearray,factor:int)->bytearray:
79+
"""
80+
Duplicate each 16-bit sample `factor` times.
81+
Input: interleaved L,R,L,R... (or mono)
82+
Output: same layout, each sample repeated `factor` times.
83+
"""
84+
iffactor==1:
85+
returnraw
86+
87+
upsampled=bytearray(len(raw)*factor)
88+
out_idx=0
89+
# each sample = 2 bytes
90+
foriinrange(0,len(raw),2):
91+
lo=raw[i]
92+
hi=raw[i+1]
93+
for_inrange(factor):
94+
upsampled[out_idx]=lo
95+
upsampled[out_idx+1]=hi
96+
out_idx+=2
97+
returnupsampled
98+
99+
# ------------------------------------------------------------------
100+
# Main playback routine
101+
# ------------------------------------------------------------------
71102
@classmethod
72103
defplay_wav(cls,filename):
73104
cls._keep_running=True
@@ -77,15 +108,28 @@ def play_wav(cls, filename):
77108
file_size=st[6]
78109
print(f"File size:{file_size} bytes")
79110

80-
data_start,data_size,sample_rate,channels=cls.find_data_chunk(f)
81-
print(f"data chunk:{data_size} bytes @{sample_rate} Hz,{channels}-channel")
111+
# ----- parse header ------------------------------------------------
112+
data_start,data_size,original_rate,channels=cls.find_data_chunk(f)
113+
114+
# ----- decide playback rate (force >= 22050 Hz) --------------------
115+
target_rate=22050
116+
iforiginal_rate>=target_rate:
117+
playback_rate=original_rate
118+
upsample_factor=1
119+
else:
120+
# find smallest integer factor so original * factor >= target
121+
upsample_factor= (target_rate+original_rate-1)//original_rate
122+
playback_rate=original_rate*upsample_factor
123+
124+
print(f"Original:{original_rate} Hz → Playback:{playback_rate} Hz "
125+
f"(factor{upsample_factor}),{channels}-ch")
82126

83127
ifdata_size>file_size-data_start:
84128
data_size=file_size-data_start
85129

86-
# ---- I2S init ------------------------------------------------
87-
i2s_format=machine.I2S.MONOifchannels==1elsemachine.I2S.STEREO
130+
# ----- I2S init ----------------------------------------------------
88131
try:
132+
i2s_format=machine.I2S.MONOifchannels==1elsemachine.I2S.STEREO
89133
cls._i2s=machine.I2S(
90134
0,
91135
sck=machine.Pin(2,machine.Pin.OUT),
@@ -94,18 +138,18 @@ def play_wav(cls, filename):
94138
mode=machine.I2S.TX,
95139
bits=16,
96140
format=i2s_format,
97-
rate=sample_rate,
141+
rate=playback_rate,
98142
ibuf=32000
99143
)
100144
exceptExceptionase:
101145
print(f"Warning: simulating playback (I2S init failed):{e}")
102146

103-
print(f"Playing{data_size} bytes (vol{cls._volume}%) …")
147+
print(f"Playing{data_size}originalbytes (vol{cls._volume}%) …")
104148
f.seek(data_start)
105149

150+
# ----- Viper volume scaler (works on any buffer) -------------------
106151
@micropython.viper
107152
defscale_audio(buf:ptr8,num_bytes:int,scale_fixed:int):
108-
# Process 16-bit samples (2 bytes each)
109153
foriinrange(0,num_bytes,2):
110154
lo=int(buf[i])
111155
hi=int(buf[i+1])
@@ -121,39 +165,43 @@ def scale_audio(buf: ptr8, num_bytes: int, scale_fixed: int):
121165
buf[i+1]= (sample>>8)&255
122166

123167
chunk_size=4096
124-
bytes_per_sample=2*channels# 2 bytes per channel
125-
total=0
168+
bytes_per_original_sample=2*channels# 2 bytes per channel
169+
total_original=0
126170

127-
whiletotal<data_size:
171+
whiletotal_original<data_size:
128172
ifnotcls._keep_running:
129173
print("Playback stopped by user.")
130174
break
131175

132-
to_read=min(chunk_size,data_size-total)
133-
# Ensure we read full samples
134-
to_read-= (to_read%bytes_per_sample)
176+
# read a chunk of *original* data
177+
to_read=min(chunk_size,data_size-total_original)
178+
to_read-= (to_read%bytes_per_original_sample)
135179
ifto_read<=0:
136180
break
137181

138182
raw=bytearray(f.read(to_read))
139183
ifnotraw:
140184
break
141185

142-
# Apply volume scaling (in-place, per sample)
186+
# ----- up-sample if needed ---------------------------------
187+
ifupsample_factor>1:
188+
raw=cls._upsample_buffer(raw,upsample_factor)
189+
190+
# ----- volume scaling ---------------------------------------
143191
scale=cls._volume/100.0
144192
ifscale<1.0:
145193
scale_fixed=int(scale*32768)
146194
scale_audio(raw,len(raw),scale_fixed)
147195

148-
#Write to I2S (stereo interleaves L,R,L,R...)
196+
#----- output ------------------------------------------------
149197
ifcls._i2s:
150198
cls._i2s.write(raw)
151199
else:
152-
#Simulate timing
153-
num_samples=len(raw)//bytes_per_sample
154-
time.sleep(num_samples/sample_rate)
200+
#simulate timing with the *playback* rate
201+
num_samples=len(raw)//(2*channels)
202+
time.sleep(num_samples/playback_rate)
155203

156-
total+=len(raw)
204+
total_original+=to_read# count original bytes only
157205

158206
print("Playback finished.")
159207
exceptExceptionase:

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