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sbc decoder: find H2 syncword

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This commit is contained in:
Milanka Ringwald 2016-07-08 12:49:37 +02:00
parent 05c5673442
commit be25a7a91f
1 changed files with 24 additions and 1 deletions
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25
test/sbc/sbc_decoder.py
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@ -10,8 +10,29 @@ V = np.zeros(shape = (2, 10*2*8))
N = np.zeros(shape = (16,8))
total_time_ms = 0
mSBC_enabled = 1
H2_first_byte = 0
H2_second_byte = 0
def find_syncword(h2_first_byte, h2_second_byte):
if h2_first_byte != 1:
return -1
hn = h2_second_byte >> 4
ln = h2_second_byte & 0x0F
if ln == 8:
sn0 = hn & 3
sn1 = hn >> 2
if sn0 != sn1:
return -1
if sn0 not in [0,3]:
return -1
return sn0
def sbc_unpack_frame(fin, available_bytes, frame):
global H2_first_byte, H2_second_byte
if available_bytes == 0:
print "no available_bytes"
raise TypeError
@ -19,7 +40,8 @@ def sbc_unpack_frame(fin, available_bytes, frame):
frame.syncword = get_bits(fin,8)
if mSBC_enabled:
if frame.syncword != 173:
print ("out of sync %02x" % frame.syncword)
H2_first_byte = H2_second_byte
H2_second_byte = frame.syncword
return -1
else:
if frame.syncword != 156:
@ -64,6 +86,7 @@ def sbc_unpack_frame(fin, available_bytes, frame):
print "alloc : ", frame.allocation_method
print "mode : ", frame.channel_mode
print "scale factor: ", frame.scale_factor
print "syncword: ", find_syncword(H2_first_byte, H2_second_byte)
crc = calculate_crc(frame)
if crc != frame.crc_check: