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sbc: fix mSBC CRC calculation

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This commit is contained in:
Matthias Ringwald 2016-07-08 12:49:05 +02:00
parent 05c5673442
commit 042beff1a9
2 changed files with 38 additions and 41 deletions
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11
test/sbc/sbc.py
View File

@ -207,6 +207,7 @@ class SBCFrame:
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)
@ -567,7 +568,15 @@ def calculate_crc(frame):
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

68
test/sbc/sbc_decoder.py
View File

@ -26,67 +26,54 @@ def sbc_unpack_frame(fin, available_bytes, frame):
print ("out of sync %02x" % frame.syncword)
return -1
frame.sampling_frequency = get_bits(fin,2)
frame.nr_blocks = nr_blocks[get_bits(fin,2)]
frame.channel_mode = get_bits(fin,2)
if mSBC_enabled:
frame.sampling_frequency = 0 # == 16 kHz
frame.nr_blocks = 15
frame.channel_mode = MONO
frame.allocation_method = LOUDNESS
frame.nr_subbands = 8
frame.bitpool = 26
frame.reserved_for_future_use = get_bits(fin,16)
else:
frame.sampling_frequency = get_bits(fin,2)
frame.nr_blocks = nr_blocks[get_bits(fin,2)]
frame.channel_mode = get_bits(fin,2)
frame.allocation_method = get_bits(fin,1)
frame.nr_subbands = nr_subbands[get_bits(fin,1)]
frame.bitpool = get_bits(fin,8)
if frame.channel_mode == MONO:
frame.nr_channels = 1
else:
frame.nr_channels = 2
frame.allocation_method = get_bits(fin,1)
frame.nr_subbands = nr_subbands[get_bits(fin,1)]
frame.bitpool = get_bits(fin,8)
frame.crc_check = get_bits(fin,8)
frame.init(frame.nr_blocks, frame.nr_subbands, frame.nr_channels)
# read joint stereo flags
if frame.channel_mode == JOINT_STEREO:
for sb in range(frame.nr_subbands-1):
frame.join[sb] = get_bits(fin,1)
get_bits(fin,1) # RFA
frame.scale_factor = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32)
# print frame.audio_sample
# read scale factors
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
frame.scale_factor[ch][sb] = get_bits(fin, 4)
if mSBC_enabled:
#frame.nr_blocks = 16
#frame.bitpool = 26
#frame.nr_subbands = 1
print "frequency: ", frame.sampling_frequency
print "subbands: ", frame.nr_blocks/4-1
print "bitpool: ", frame.bitpool
print "blocks : ", frame.nr_blocks/4-1
print "alloc : ", frame.allocation_method
print "mode : ", frame.channel_mode
print "scale factor: ", frame.scale_factor
crc = calculate_crc(frame)
if mSBC_enabled:
crc = calculate_crc_mSBC(frame)
else:
crc = calculate_crc(frame)
if crc != frame.crc_check:
print "CRC mismatch: calculated %d, expected %d" % (crc, frame.crc_check)
exit(10)
if mSBC_enabled:
frame.nr_subbands = 8
frame.bitpool = 26
frame.nr_blocks = 15
#frame.sampling_frequency = 0
frame.init(frame.nr_blocks, frame.nr_subbands, frame.nr_channels)
if frame.channel_mode == JOINT_STEREO:
for sb in range(frame.nr_subbands-1):
frame.join[sb] = get_bits(fin,1)
get_bits(fin,1) # RFA
for ch in range(frame.nr_channels):
for sb in range(frame.nr_subbands):
frame.scale_factor[ch][sb] = get_bits(fin, 4)
return -1
print "CRC correct: %d" % crc
frame.scalefactor = np.zeros(shape=(frame.nr_channels, frame.nr_subbands), dtype = np.int32)
for ch in range(frame.nr_channels):
@ -308,6 +295,7 @@ if __name__ == "__main__":
sys.exit(1)
wavfile = infile.replace('.sbc', '-decoded.wav')
wavfile = infile.replace('.msbc', '-decoded.wav')
fout = False
implementation = "SIG"
@ -329,7 +317,7 @@ if __name__ == "__main__":
while True:
frame = SBCFrame()
if frame_count % 200 == 0:
print "== Frame %d == %d" % (frame_count, fin.tell())
print "== Frame %d == offset %d" % (frame_count, fin.tell())
err = sbc_unpack_frame(fin, file_size - fin.tell(), frame)
if err: