def trimwavfile(wavfilename, wavoutfilename, start, duration=None, gain=None):
with file(wavfilename, 'rb') as f:
# read in the headers
headers = f.read(20)
subchunk1size = common.LSBUint32(headers[16:20])
headers += f.read(subchunk1size)
subchunk2id = f.read(4)
subchunk2size = common.LSBUint32(f.read(4))
# check for a PCM file format
if headers[:4]!='RIFF' or headers[8:12]!='WAVE' or \
headers[12:16]!='fmt ' or common.LSBUint16(headers[20:22])!=1:
# not a PCM file
raise TypeError
subchunk2start = 20 + subchunk1size
subchunk2datastart = subchunk2start + 8
samplerate = common.LSBUint32(headers[24:28])
blockalign = common.LSBUint16(headers[32:34])
# compute new start & duration
new_start = int(start * samplerate) * blockalign
new_size = subchunk2size - new_start
if duration is not None:
i = int(duration * samplerate) * blockalign
if i < new_size:
new_size = i
# go get it
f.seek(new_start, 1)
open(wavoutfilename, 'wb').write("".join([
'RIFF',
common.LSBstr32(4 + 8 + subchunk1size + 8 + new_size), headers[8:],
'data',
common.LSBstr32(new_size),
f.read(new_size)
]))
if gain is not None:
adjustwavfilevolume(wavoutfilename, gain)
def trimwavdata(wavedatain, start, duration=None):
# check for a PCM file format
if wavedatain[:4]!='RIFF' or wavedatain[8:12]!='WAVE' or \
wavedatain[12:16]!='fmt ' or common.LSBUint16(wavedatain[20:22])!=1:
raise ValueError, 'not a PCM file'
subchunk1size = common.LSBUint32(wavedatain[16:20])
subchunk2start = 20 + subchunk1size
subchunk2size = common.LSBUint32(wavedatain[subchunk2start +
4:subchunk2start + 8])
subchunk2datastart = subchunk2start + 8
samplerate = common.LSBUint32(wavedatain[24:28])
blockalign = common.LSBUint16(wavedatain[32:34])
# compute new start & duration
new_start = int(start * samplerate) * blockalign
newsubchunk2datastart = subchunk2datastart + new_start
new_size = subchunk2size - new_start
if duration is not None:
i = int(duration * samplerate) * blockalign
if i < new_size:
new_size = i
# return new data
return 'RIFF'+common.LSBstr32(4+8+subchunk1size+8+new_size)+\
wavedatain[8:subchunk2start]+\
'data'+common.LSBstr32(new_size)+\
wavedatain[newsubchunk2datastart:newsubchunk2datastart+new_size]
def adjustwavfilevolume(wavfilename, gain):
""" Ajdust the volume of a wav file.
"""
with file(wavfilename, 'rb') as f:
# read in the headers
headers = f.read(20)
subchunk1size = common.LSBUint32(headers[16:20])
headers += f.read(subchunk1size)
headers += f.read(8) # 4 byte ID and 4 byte length
subchunk2size = common.LSBUint32(headers[-4:])
bitspersample = common.LSBUint16(headers[34:36])
if bitspersample != 16:
print 'Volume adjustment only works with 16-bit wav file', bitspersample
return
sample_num = subchunk2size / 2 # always 16-bit per channel per sample
temp_name = common.gettempfilename("wav")
with file(temp_name, 'wb') as f_temp:
f_temp.write(headers)
delta = pow(10.0, (gain / 10.0))
for i in range(sample_num):
d = int(struct.unpack('<h', f.read(2))[0] * delta)
if d > 32767:
d = 32767
elif d < -32768:
d = -32768
f_temp.write(struct.pack('<h', d))
os.remove(wavfilename)
os.rename(temp_name, wavfilename)
def convertbmptolgbit(bmp_data):
"""Takes a BMP image file and returns BIT image file (LG proprietary)
@param bit_data: 8BPP or 24BPP BMP image file data
@return: 16BPP LGBIT image file data
"""
# This function only exists for the LG proprietary images (wallpaper, etc.)
# on the LG-VX3200.
if bmp_data[0:2] != 'BM':
return None
width = common.LSBUint32(bmp_data[18:22])
height = common.LSBUint32(bmp_data[22:26])
offset = common.LSBUint32(bmp_data[10:14])
bpp = common.LSBUint16(bmp_data[28:30])
img = common.LSBstr16(width)
img += common.LSBstr16(height)
# Now on to the char data
if bpp == 8:
# 8BPP (paletted) BMP data
palette = bmp_data[54:54 + 256 * 4]
for h in range(height):
for w in range(width):
bitind = (height - h - 1) * width + w + offset
palind = ord(bmp_data[bitind:bitind + 1]) * 4
blue = ord(palette[palind:palind + 1])
green = ord(palette[palind + 1:palind + 2])
red = ord(palette[palind + 2:palind + 3])
bitval = ((red & 0xf8) << 8) | ((green & 0xfc) << 3) | (
(blue & 0xf8) >> 3)
img += common.LSBstr16(bitval)
elif bpp == 24:
# 24BPP (non-paletted) BMP data
for h in range(height):
for w in range(width):
bitind = (height - h - 1) * width * 3 + (w * 3) + offset
blue = ord(bmp_data[bitind:bitind + 1])
green = ord(bmp_data[bitind + 1:bitind + 2])
red = ord(bmp_data[bitind + 2:bitind + 3])
bitval = ((red & 0xf8) << 8) | ((green & 0xfc) << 3) | (
(blue & 0xf8) >> 3)
img += common.LSBstr16(bitval)
else:
return None
return img