#!/usr/bin/env python
import numpy as np
import wave
import struct
import sys
import time
# channel mode
MONO = 0
DUAL_CHANNEL = 1
STEREO = 2
JOINT_STEREO = 3
channel_modes = ["MONO", "DUAL CHANNEL", "STEREO", "JOINT STEREO"]
# allocation method
LOUDNESS = 0
SNR = 1
allocation_methods = ["LOUDNESS", "SNR"]
sampling_frequencies = [16000, 32000, 44100, 48000]
nr_blocks = [4, 8, 12, 16]
nr_subbands = [4, 8]
time_ms = lambda: int(round(time.time() * 1000))
def allocation_method_to_str(allocation_method):
global allocation_methods
return allocation_methods[allocation_method]
def channel_mode_to_str(channel_mode):
global channel_modes
return channel_modes[channel_mode]
def sampling_frequency_to_str(sampling_frequency):
global sampling_frequencies
return sampling_frequencies[sampling_frequency]
def sampling_frequency_index(sampling_frequency):
global sampling_frequencies
for index, value in enumerate(sampling_frequencies):
if value == sampling_frequency:
return index
return -1
Proto_4_40 = [
0.00000000E+00, 5.36548976E-04, 1.49188357E-03, 2.73370904E-03,
3.83720193E-03, 3.89205149E-03, 1.86581691E-03, -3.06012286E-03,
1.09137620E-02, 2.04385087E-02, 2.88757392E-02, 3.21939290E-02,
2.58767811E-02, 6.13245186E-03, -2.88217274E-02, -7.76463494E-02,
1.35593274E-01, 1.94987841E-01, 2.46636662E-01, 2.81828203E-01,
2.94315332E-01, 2.81828203E-01, 2.46636662E-01, 1.94987841E-01,
-1.35593274E-01, -7.76463494E-02, -2.88217274E-02, 6.13245186E-03,
2.58767811E-02, 3.21939290E-02, 2.88757392E-02, 2.04385087E-02,
-1.09137620E-02, -3.06012286E-03, 1.86581691E-03, 3.89205149E-03,
3.83720193E-03, 2.73370904E-03, 1.49188357E-03, 5.36548976E-04
]
Proto_8_80 = [
0.00000000E+00, 1.56575398E-04, 3.43256425E-04, 5.54620202E-04,
8.23919506E-04, 1.13992507E-03, 1.47640169E-03, 1.78371725E-03,
2.01182542E-03, 2.10371989E-03, 1.99454554E-03, 1.61656283E-03,
9.02154502E-04, -1.78805361E-04, -1.64973098E-03, -3.49717454E-03,
5.65949473E-03, 8.02941163E-03, 1.04584443E-02, 1.27472335E-02,
1.46525263E-02, 1.59045603E-02, 1.62208471E-02, 1.53184106E-02,
1.29371806E-02, 8.85757540E-03, 2.92408442E-03, -4.91578024E-03,
-1.46404076E-02, -2.61098752E-02, -3.90751381E-02, -5.31873032E-02,
6.79989431E-02, 8.29847578E-02, 9.75753918E-02, 1.11196689E-01,
1.23264548E-01, 1.33264415E-01, 1.40753505E-01, 1.45389847E-01,
1.46955068E-01, 1.45389847E-01, 1.40753505E-01, 1.33264415E-01,
1.23264548E-01, 1.11196689E-01, 9.75753918E-02, 8.29847578E-02,
-6.79989431E-02, -5.31873032E-02, -3.90751381E-02, -2.61098752E-02,
-1.46404076E-02, -4.91578024E-03, 2.92408442E-03, 8.85757540E-03,
1.29371806E-02, 1.53184106E-02, 1.62208471E-02, 1.59045603E-02,
1.46525263E-02, 1.27472335E-02, 1.04584443E-02, 8.02941163E-03,
-5.65949473E-03, -3.49717454E-03, -1.64973098E-03, -1.78805361E-04,
9.02154502E-04, 1.61656283E-03, 1.99454554E-03, 2.10371989E-03,
2.01182542E-03, 1.78371725E-03, 1.47640169E-03, 1.13992507E-03,
8.23919506E-04, 5.54620202E-04, 3.43256425E-04, 1.56575398E-04
]
crc_table = [
0x00, 0x1D, 0x3A, 0x27, 0x74, 0x69, 0x4E, 0x53,
0xE8, 0xF5, 0xD2, 0xCF, 0x9C, 0x81, 0xA6, 0xBB,
0xCD, 0xD0, 0xF7, 0xEA, 0xB9, 0xA4, 0x83, 0x9E,
0x25, 0x38, 0x1F, 0x02, 0x51, 0x4C, 0x6B, 0x76,
0x87, 0x9A, 0xBD, 0xA0, 0xF3, 0xEE, 0xC9, 0xD4,
0x6F, 0x72, 0x55, 0x48, 0x1B, 0x06, 0x21, 0x3C,
0x4A, 0x57, 0x70, 0x6D, 0x3E, 0x23, 0x04, 0x19,
0xA2, 0xBF, 0x98, 0x85, 0xD6, 0xCB, 0xEC, 0xF1,
0x13, 0x0E, 0x29, 0x34, 0x67, 0x7A, 0x5D, 0x40,
0xFB, 0xE6, 0xC1, 0xDC, 0x8F, 0x92, 0xB5, 0xA8,
0xDE, 0xC3, 0xE4, 0xF9, 0xAA, 0xB7, 0x90, 0x8D,
0x36, 0x2B, 0x0C, 0x11, 0x42, 0x5F, 0x78, 0x65,
0x94, 0x89, 0xAE, 0xB3, 0xE0, 0xFD, 0xDA, 0xC7,
0x7C, 0x61, 0x46, 0x5B, 0x08, 0x15, 0x32, 0x2F,
0x59, 0x44, 0x63, 0x7E, 0x2D, 0x30, 0x17, 0x0A,
0xB1, 0xAC, 0x8B, 0x96, 0xC5, 0xD8, 0xFF, 0xE2,
0x26, 0x3B, 0x1C, 0x01, 0x52, 0x4F, 0x68, 0x75,
0xCE, 0xD3, 0xF4, 0xE9, 0xBA, 0xA7, 0x80, 0x9D,
0xEB, 0xF6, 0xD1, 0xCC, 0x9F, 0x82, 0xA5, 0xB8,
0x03, 0x1E, 0x39, 0x24, 0x77, 0x6A, 0x4D, 0x50,
0xA1, 0xBC, 0x9B, 0x86, 0xD5, 0xC8, 0xEF, 0xF2,
0x49, 0x54, 0x73, 0x6E, 0x3D, 0x20, 0x07, 0x1A,
0x6C, 0x71, 0x56, 0x4B, 0x18, 0x05, 0x22, 0x3F,
0x84, 0x99, 0xBE, 0xA3, 0xF0, 0xED, 0xCA, 0xD7,
0x35, 0x28, 0x0F, 0x12, 0x41, 0x5C, 0x7B, 0x66,
0xDD, 0xC0, 0xE7, 0xFA, 0xA9, 0xB4, 0x93, 0x8E,
0xF8, 0xE5, 0xC2, 0xDF, 0x8C, 0x91, 0xB6, 0xAB,
0x10, 0x0D, 0x2A, 0x37, 0x64, 0x79, 0x5E, 0x43,
0xB2, 0xAF, 0x88, 0x95, 0xC6, 0xDB, 0xFC, 0xE1,
0x5A, 0x47, 0x60, 0x7D, 0x2E, 0x33, 0x14, 0x09,
0x7F, 0x62, 0x45, 0x58, 0x0B, 0x16, 0x31, 0x2C,
0x97, 0x8A, 0xAD, 0xB0, 0xE3, 0xFE, 0xD9, 0xC4
]
# offset table for 4-subbands
offset4 = np.array([[ -1, 0, 0, 0 ],
[ -2, 0, 0, 1 ],
[ -2, 0, 0, 1 ],
[ -2, 0, 0, 1 ]
])
# offset tables for 8-subbands
offset8 = np.array([[ -2, 0, 0, 0, 0, 0, 0, 1 ],
[ -3, 0, 0, 0, 0, 0, 1, 2 ],
[ -4, 0, 0, 0, 0, 0, 1, 2 ],
[ -4, 0, 0, 0, 0, 0, 1, 2 ]
])
def calculate_scalefactor(max_subbandsample):
x = 0
while True:
y = 1 << (x + 1)
if y > max_subbandsample:
break
x += 1
return (x,y)
def calculate_max_subbandsample(nr_blocks, nr_channels, nr_subbands, sb_sample):
max_subbandsample = np.zeros(shape = (nr_channels, nr_subbands))
for blk in range(nr_blocks):
for ch in range(nr_channels):
for sb in range(nr_subbands):
m = abs(sb_sample[blk][ch][sb])
if max_subbandsample[ch][sb] < m:
max_subbandsample[ch][sb] = m
return max_subbandsample
def calculate_scalefactors(nr_blocks, nr_channels, nr_subbands, sb_sample):
scale_factor = np.zeros(shape=(nr_channels, nr_subbands), dtype = np.int32)
scalefactor = np.zeros(shape=(nr_channels, nr_subbands), dtype = np.int32)
max_subbandsample = calculate_max_subbandsample(nr_blocks, nr_channels, nr_subbands, sb_sample)
for ch in range(nr_channels):
for sb in range(nr_subbands):
(scale_factor[ch][sb], scalefactor[ch][sb]) = calculate_scalefactor(max_subbandsample[ch][sb])
return scale_factor, scalefactor
def calculate_channel_mode_and_scale_factors(frame, force_channel_mode):
frame.scale_factor, frame.scalefactor = calculate_scalefactors(frame.nr_blocks, frame.nr_channels, frame.nr_subbands, frame.sb_sample)
if frame.nr_channels == 1:
frame.channel_mode = MONO
return
frame.join = np.zeros(frame.nr_subbands, dtype = np.uint8)
if force_channel_mode == STEREO:
frame.channel_mode = STEREO
return
sb_sample = np.zeros(shape = (frame.nr_blocks,2,frame.nr_subbands), dtype = np.int32)
for blk in range(frame.nr_blocks):
for sb in range(frame.nr_subbands):
sb_sample[blk][0][sb] = (frame.sb_sample[blk][0][sb] + frame.sb_sample[blk][1][sb])/2
sb_sample[blk][1][sb] = (frame.sb_sample[blk][0][sb] - frame.sb_sample[blk][1][sb])/2
scale_factor, scalefactor = calculate_scalefactors(frame.nr_blocks, frame.nr_channels, frame.nr_subbands, sb_sample)
for sb in range(frame.nr_subbands-1):
suma = frame.scale_factor[0][sb] + frame.scale_factor[1][sb]
sumb = scale_factor[0][sb] + scale_factor[1][sb]
if suma > sumb or force_channel_mode == JOINT_STEREO:
frame.channel_mode = JOINT_STEREO
frame.join[sb] = 1
frame.scale_factor[0][sb] = scale_factor[0][sb]
frame.scale_factor[1][sb] = scale_factor[1][sb]
frame.scalefactor[0][sb] = scalefactor[0][sb]
frame.scalefactor[1][sb] = scalefactor[1][sb]
for blk in range(frame.nr_blocks):
frame.sb_sample[blk][0][sb] = sb_sample[blk][0][sb]
frame.sb_sample[blk][1][sb] = sb_sample[blk][1][sb]
class SBCFrame:
syncword = 0
sampling_frequency = 0
nr_blocks = 0
channel_mode = 0
nr_channels = 0
allocation_method = 0
nr_subbands = 0
bitpool = 0
crc_check = 0
reserved_for_future_use = 0
# pro subband - 1
join = np.zeros(8, dtype = np.uint8)
scale_factor = np.zeros(shape=(2, 8), dtype = np.int32)
scalefactor = np.zeros(shape=(2, 8), dtype = np.int32)
audio_sample = np.zeros(shape = (16,2,8), dtype = np.uint16)
sb_sample = np.zeros(shape = (16,2,8), dtype = np.int32)
X = np.zeros(8, dtype = np.int16)
EX = np.zeros(8)
pcm = np.zeros(shape=(2, 8*16), dtype = np.int16)
bits = np.zeros(shape=(2, 8))
levels = np.zeros(shape=(2, 8), dtype = np.int32)
def __init__(self, nr_blocks=16, nr_subbands=4, nr_channels=1, bitpool=31, sampling_frequency=44100, allocation_method = 0, force_channel_mode = 0):
self.nr_blocks = nr_blocks
self.nr_subbands = nr_subbands
self.nr_channels = nr_channels
self.sampling_frequency = sampling_frequency_index(sampling_frequency)
self.bitpool = bitpool
self.allocation_method = allocation_method
self.init(nr_blocks, nr_subbands, nr_channels)
self.channel_mode = force_channel_mode
return
def init(self, nr_blocks, nr_subbands, nr_channels):
self.scale_factor = np.zeros(shape=(nr_channels, nr_subbands), dtype = np.int32)
self.scalefactor = np.zeros(shape=(nr_channels, nr_subbands), dtype = np.int32)
self.audio_sample = np.zeros(shape=(nr_blocks, nr_channels, nr_subbands), dtype = np.uint16)
self.sb_sample = np.zeros(shape=(nr_blocks, nr_channels, nr_subbands), dtype = np.int32)
self.levels = np.zeros(shape=(nr_channels, nr_subbands), dtype = np.int32)
self.pcm = np.zeros(shape=(nr_channels, nr_subbands*nr_blocks), dtype = np.int16)
self.join = np.zeros(nr_subbands, dtype = np.uint8)
self.X = np.zeros(nr_subbands, dtype = np.int16)
self.EX = np.zeros(nr_subbands)
def dump_audio_samples(self, blk, ch):
print self.audio_sample[blk][ch]
def dump_subband_samples(self, blk, ch):
print self.sb_sample[blk][ch]
def dump_state(self):
res = "SBCFrameHeader state:"
res += "\n - nr channels %d" % self.nr_channels
res += "\n - nr blocks %d" % self.nr_blocks
res += "\n - nr subbands %d" % self.nr_subbands
res += "\n - scale factors: %s" % self.scale_factor
res += "\n - levels: %s" % self.levels
res += "\n - join: %s" % self.join
res += "\n - bits: %s" % self.bits
print res
def __str__(self):
res = "SBCFrameHeader:"
res += "\n - syncword %x" % self.syncword
res += "\n - sampling frequency %d Hz" % sampling_frequency_to_str(self.sampling_frequency)
res += "\n - nr channels %d" % self.nr_channels
res += "\n - nr blocks %d" % self.nr_blocks
res += "\n - nr subbands %d" % self.nr_subbands
res += "\n - channel mode %s" % channel_mode_to_str(self.channel_mode)
res += "\n - allocation method %s" % allocation_method_to_str(self.allocation_method)
res += "\n - bitpool %d" % self.bitpool
res += "\n - crc check %x" % self.crc_check
return res
def sbc_bit_allocation_stereo_joint(frame):
bitneed = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32)
bits = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32)
loudness = 0
if frame.allocation_method == SNR:
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
bitneed[ch][sb] = frame.scale_factor[ch][sb]
else:
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
if frame.scale_factor[ch][sb] == 0:
bitneed[ch][sb] = -5
else:
if frame.nr_subbands == 4:
loudness = frame.scale_factor[ch][sb] - offset4[frame.sampling_frequency][sb]
else:
loudness = frame.scale_factor[ch][sb] - offset8[frame.sampling_frequency][sb]
if loudness > 0:
bitneed[ch][sb] = loudness/2
else:
bitneed[ch][sb] = loudness
# search the maximum bitneed index
max_bitneed = 0
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
if bitneed[ch][sb] > max_bitneed:
max_bitneed = bitneed[ch][sb]
# calculate how many bitslices fit into the bitpool
bitcount = 0
slicecount = 0
bitslice = max_bitneed + 1 #/* init just above the largest sf */
while True:
bitslice -= 1
bitcount += slicecount
slicecount = 0
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
if (bitneed[ch][sb] > bitslice+1) and (bitneed[ch][sb] < bitslice+16):
slicecount += 1
elif bitneed[ch][sb] == bitslice + 1:
slicecount += 2
if bitcount + slicecount >= frame.bitpool:
break
if bitcount + slicecount == frame.bitpool:
bitcount += slicecount
bitslice -= 1
# bits are distributed until the last bitslice is reached
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
if bitneed[ch][sb] < bitslice+2:
bits[ch][sb]=0
else:
bits[ch][sb] = min(bitneed[ch][sb]-bitslice,16)
ch = 0
sb = 0
while bitcount < frame.bitpool and sb < frame.nr_subbands:
if bits[ch][sb] >= 2 and bits[ch][sb] < 16:
bits[ch][sb] += 1
bitcount += 1
elif (bitneed[ch][sb] == bitslice+1) and (frame.bitpool > bitcount+1):
bits[ch][sb] = 2
bitcount += 2
if ch == 1:
ch = 0
sb += 1
else:
ch = 1
ch = 0
sb = 0
while bitcount < frame.bitpool and sb < frame.nr_subbands:
if bits[ch][sb] < 16:
bits[ch][sb]+=1
bitcount+=1
if ch == 1:
ch = 0
sb += 1
else:
ch = 1
if bits.sum() != frame.bitpool:
print "bit allocation failed, bitpool %d, allocated %d" % (bits.sum() , frame.bitpool)
exit(1)
return bits
def sbc_bit_allocation_mono_dual(frame):
#print "Bit allocation for mono/dual channel"
bitneed = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32)
bits = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32)
loudness = 0
for ch in range(frame.nr_channels):
# bitneed values are derived from the scale factors
if frame.allocation_method == SNR:
for sb in range(frame.nr_subbands):
bitneed[ch][sb] = frame.scale_factor[ch][sb]
else:
for sb in range(frame.nr_subbands):
if frame.scale_factor[ch][sb] == 0:
bitneed[ch][sb] = -5
else:
if frame.nr_subbands == 4:
loudness = frame.scale_factor[ch][sb] - offset4[frame.sampling_frequency][sb]
else:
loudness = frame.scale_factor[ch][sb] - offset8[frame.sampling_frequency][sb]
if loudness > 0:
bitneed[ch][sb] = loudness/2
else:
bitneed[ch][sb] = loudness
# search the maximum bitneed index
max_bitneed = 0
for sb in range(frame.nr_subbands):
if bitneed[ch][sb] > max_bitneed:
max_bitneed = bitneed[ch][sb]
# calculate how many bitslices fit into the bitpool
bitcount = 0
slicecount = 0
bitslice = max_bitneed + 1
while True:
bitslice = bitslice - 1
bitcount = bitcount + slicecount
slicecount = 0
for sb in range(frame.nr_subbands):
if (bitneed[ch][sb] > bitslice+1) and (bitneed[ch][sb] < bitslice+16):
slicecount = slicecount + 1
elif bitneed[ch][sb] == bitslice + 1:
slicecount = slicecount + 2
if bitcount + slicecount >= frame.bitpool:
break
if bitcount + slicecount == frame.bitpool:
bitcount = bitcount + slicecount
bitslice = bitslice - 1
for sb in range(frame.nr_subbands):
if bitneed[ch][sb] < bitslice+2 :
bits[ch][sb]=0;
else:
bits[ch][sb] = min(bitneed[ch][sb]-bitslice,16)
sb = 0
while bitcount < frame.bitpool and sb < frame.nr_subbands:
if bits[ch][sb] >= 2 and bits[ch][sb] < 16:
bits[ch][sb] = bits[ch][sb] + 1
bitcount = bitcount + 1
elif (bitneed[ch][sb] == bitslice+1) and (frame.bitpool > bitcount+1):
bits[ch][sb] = 2
bitcount += 2
sb = sb + 1
sb = 0
while bitcount < frame.bitpool and sb < frame.nr_subbands:
if bits[ch][sb] < 16:
bits[ch][sb] = bits[ch][sb] + 1
bitcount = bitcount + 1
sb = sb + 1
return bits
def sbc_bit_allocation(frame):
if frame.channel_mode == MONO or frame.channel_mode == DUAL_CHANNEL:
return sbc_bit_allocation_mono_dual(frame)
elif frame.channel_mode == STEREO or frame.channel_mode == JOINT_STEREO:
return sbc_bit_allocation_stereo_joint(frame)
else:
print "Wrong channel mode ", frame.channel_mode
return -1
def sbc_sampling_frequency_index(sample_rate):
sbc_sampling_frequency_index = 0
for i in range(len(sampling_frequency)):
if sample_rate == sampling_frequency[i]:
sbc_sampling_frequency_index = i
break
return sbc_sampling_frequency_index
def sbc_crc8(data, data_len):
crc = 0x0f
j = 0
for i in range(data_len / 8):
crc = crc_table[crc ^ data[i]]
j = i + 1
bits_left = data_len%8
if bits_left:
octet = data[j]
for i in range(data_len%8):
bit = ((octet ^ crc) & 0x80) >> 7
if bit:
bit = 0x1d
crc = ((crc & 0x7f) << 1) ^ bit
octet = octet << 1
return crc
bitstream = None
bitstream_index = -1
bitstream_bits_available = 0
def init_bitstream():
global bitstream, bitstream_bits_available, bitstream_index
bitstream = []
bitstream_index = -1
bitstream_bits_available = 0
def add_bit(bit):
global bitstream, bitstream_bits_available, bitstream_index
if bitstream_bits_available == 0:
bitstream.append(0)
bitstream_bits_available = 8
bitstream_index += 1
bitstream[bitstream_index] |= bit << (bitstream_bits_available - 1)
bitstream_bits_available -= 1
def add_bits(bits, len):
global bitstream, bitstream_bits_available
for i in range(len):
add_bit((bits >> (len-1-i)) & 1)
ibuffer = None
ibuffer_count = 0
def get_bit(fin):
global ibuffer, ibuffer_count
if ibuffer_count == 0:
ibuffer = ord(fin.read(1))
ibuffer_count = 8
bit = (ibuffer >> 7) & 1
ibuffer = ibuffer << 1
ibuffer_count = ibuffer_count - 1
return bit
def drop_remaining_bits():
global ibuffer_count
#print "dropping %d bits" % ibuffer_count
ibuffer_count = 0
def get_bits(fin, bit_count):
bits = 0
for i in range(bit_count):
bits = (bits << 1) | get_bit(fin)
# print "get bits: %d -> %02x" %(bit_count, bits)
return bits
def calculate_crc(frame):
global bitstream, bitstream_bits_available, bitstream_index
init_bitstream()
add_bits(frame.sampling_frequency, 2)
add_bits(frame.nr_blocks/4-1, 2)
add_bits(frame.channel_mode, 2)
add_bits(frame.allocation_method, 1)
add_bits(frame.nr_subbands/4-1, 1)
add_bits(frame.bitpool, 8)
if frame.channel_mode == JOINT_STEREO:
for sb in range(frame.nr_subbands):
add_bits(frame.join[sb],1)
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
add_bits(frame.scale_factor[ch][sb], 4)
bitstream_len = (bitstream_index + 1) * 8
if bitstream_bits_available:
bitstream_len -= bitstream_bits_available
return sbc_crc8(bitstream, bitstream_len)
def calculate_crc_mSBC(frame):
init_bitstream()
add_bits(frame.reserved_for_future_use, 16)
for sb in range(8):
add_bits(frame.scale_factor[0][sb], 4)
bitstream_len = (bitstream_index + 1) * 8
if bitstream_bits_available:
bitstream_len -= bitstream_bits_available
return sbc_crc8(bitstream, bitstream_len)
def frame_to_bitstream(frame):
global bitstream, bitstream_bits_available, bitstream_index
init_bitstream()
add_bits(frame.syncword, 8)
add_bits(frame.sampling_frequency, 2)
add_bits(frame.nr_blocks/4-1, 2)
add_bits(frame.channel_mode, 2)
add_bits(frame.allocation_method, 1)
add_bits(frame.nr_subbands/4-1, 1)
add_bits(frame.bitpool, 8)
add_bits(frame.crc_check, 8)
if frame.channel_mode == JOINT_STEREO:
for sb in range(frame.nr_subbands-1):
add_bits(frame.join[sb],1)
add_bits(0,1)
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
add_bits(frame.scale_factor[ch][sb], 4)
for blk in range(frame.nr_blocks):
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
add_bits(frame.audio_sample[blk][ch][sb], frame.bits[ch][sb])
bitstream_bits_available = 0
return bitstream
def mse(a,b):
count = 1
for i in a.shape:
count *= i
delta = a - b
sqr = delta ** 2
res = sqr.sum()*1.0/count
# res = ((a - b) ** 2).mean()
return res