1#!/usr/bin/env python 2import numpy as np 3import wave 4import struct 5import sys 6from sbc import * 7 8X = np.zeros(shape=(2,80), dtype = np.int16) 9 10 11def fetch_samples_for_next_sbc_frame(fin, frame): 12 nr_samples = frame.nr_blocks * frame.nr_subbands 13 raw_data = fin.readframes(nr_samples) # Returns byte data 14 fmt = "%ih" % (len(raw_data) / 2) 15 data = struct.unpack(fmt, raw_data) 16 17 if frame.nr_channels == 2: 18 for i in range(len(data)/2): 19 frame.pcm[0][i] = data[2*i] 20 frame.pcm[1][i] = data[2*i+1] 21 else: 22 for i in range(len(data)): 23 frame.pcm[0][i] = data[i] 24 25 26def sbc_frame_analysis(frame, ch, blk, C): 27 global X 28 29 M = frame.nr_subbands 30 L = 10 * M 31 M2 = 2*M 32 L2 = 2*L 33 34 Z = np.zeros(L) 35 Y = np.zeros(M2) 36 W = np.zeros(shape=(M, M2)) 37 S = np.zeros(M) 38 39 for i in range(L-1, M-1, -1): 40 X[ch][i] = X[ch][i-M] 41 for i in range(M-1, -1, -1): 42 X[ch][i] = frame.EX[M-1-i] 43 for i in range(L): 44 Z[i] = X[ch][i] * C[i] 45 46 for i in range(M2): 47 for k in range(5): 48 Y[i] += Z[i+k*M2] 49 50 for i in range(M): 51 for k in range(M2): 52 W[i][k] = np.cos((i+0.5)*(k-M/2)*np.pi/M) 53 S[i] += W[i][k] * Y[k] 54 55 for sb in range(M): 56 frame.sb_sample[blk][ch][sb] = S[sb] 57 58def sbc_analysis(frame): 59 if frame.nr_subbands == 4: 60 C = Proto_4_40 61 elif frame.nr_subbands == 8: 62 C = Proto_8_80 63 else: 64 return -1 65 66 frame.sb_sample = np.ndarray(shape=(frame.nr_blocks, frame.nr_channels, frame.nr_subbands)) 67 for ch in range(frame.nr_channels): 68 index = 0 69 for blk in range(frame.nr_blocks): 70 for sb in range(frame.nr_subbands): 71 frame.EX[sb] = frame.pcm[ch][index] 72 index+=1 73 sbc_frame_analysis(frame, ch, blk, C) 74 return 0 75 76def sbc_encode(frame): 77 err = sbc_analysis(frame) 78 if err >= 0: 79 err = sbc_quantization(frame) 80 return err 81 82def sbc_quantization(frame): 83 calculate_channel_mode_and_scale_factors(frame) 84 frame.bits = sbc_bit_allocation(frame) 85 86 # Reconstruct the Audio Samples 87 frame.levels = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32) 88 for ch in range(frame.nr_channels): 89 for sb in range(frame.nr_subbands): 90 frame.levels[ch][sb] = (1 << frame.bits[ch][sb]) - 1 #pow(2.0, frame.bits[ch][sb]) - 1 91 92 frame.syncword = 0x9c 93 frame.crc_check = calculate_crc(frame) 94 95 96 for blk in range(frame.nr_blocks): 97 for ch in range(frame.nr_channels): 98 for sb in range(frame.nr_subbands): 99 if frame.levels[ch][sb] > 0: 100 SB = frame.sb_sample[blk][ch][sb] 101 L = frame.levels[ch][sb] 102 SF = frame.scalefactor[ch][sb] 103 104 # if frame.channel_mode == JOINT_STEREO and frame.join[sb]: 105 # SB = SB * 2 106 107 frame.audio_sample[blk][ch][sb] = np.uint16(((SB * L / SF + L) - 1.0)/2.0) 108 else: 109 frame.audio_sample[blk][ch][sb] = 0 110 111 return 0 112 113def sbc_write_frame(fout, sbc_encoder_frame): 114 stream = frame_to_bitstream(sbc_encoder_frame) 115 barray = bytearray(stream) 116 fout.write(barray) 117 118if __name__ == "__main__": 119 usage = ''' 120 Usage: ./sbc_encoder.py input.wav blocks subbands bitpool allocation_method[0-LOUDNESS,1-SNR] 121 Example: ./sbc_encoder.py fanfare.wav 16 4 31 0 122 ''' 123 nr_blocks = 0 124 nr_subbands = 0 125 126 127 if (len(sys.argv) < 6): 128 print(usage) 129 sys.exit(1) 130 try: 131 infile = sys.argv[1] 132 if not infile.endswith('.wav'): 133 print(usage) 134 sys.exit(1) 135 sbcfile = infile.replace('.wav', '-encoded.sbc') 136 137 nr_blocks = int(sys.argv[2]) 138 nr_subbands = int(sys.argv[3]) 139 bitpool = int(sys.argv[4]) 140 allocation_method = int(sys.argv[5]) 141 142 fin = wave.open(infile, 'rb') 143 nr_channels = fin.getnchannels() 144 sampling_frequency = fin.getframerate() 145 nr_audio_frames = fin.getnframes() 146 147 subband_frame_count = 0 148 audio_frame_count = 0 149 nr_samples = nr_blocks * nr_subbands 150 fout = open(sbcfile, 'wb') 151 while audio_frame_count < nr_audio_frames: 152 if subband_frame_count % 200 == 0: 153 print("== Frame %d ==" % (subband_frame_count)) 154 155 sbc_encoder_frame = SBCFrame(nr_blocks, nr_subbands, nr_channels, bitpool, sampling_frequency, allocation_method) 156 fetch_samples_for_next_sbc_frame(fin, sbc_encoder_frame) 157 158 sbc_encode(sbc_encoder_frame) 159 sbc_write_frame(fout, sbc_encoder_frame) 160 161 # if subband_frame_count == 1: 162 # exit(0) 163 audio_frame_count += nr_samples 164 subband_frame_count += 1 165 166 167 fin.close() 168 fout.close() 169 print("DONE, WAV file %s encoded into SBC file %s " % (infile, sbcfile)) 170 171 172 except IOError as e: 173 print(usage) 174 sys.exit(1) 175 176 177 178 179 180