def embed_LSB(carrierFile,payloadFile,outFile):
"""Embed a message in the carrier audio using modified LSB coding
Returns audio data with the embedded payload
Parameters:
carrierFile - the name of the carrier audio file
payloadFile - the name of the payload file
outFile - the name of the file to which the package will be written
"""
from amm import wavread,wavwrite
_logInfo("Encoding...")
# read in the carrier file
samples,params = wavread(carrierFile,bSplit=False)
samples = samples.tolist()
sampleLength = len(samples)
# Read the payload in and store it as a list of integers
payload = None
payloadData = None
try:
payload = open(payloadFile, 'rb')
payloadData = bytesToInts(payload.read())
except (IOerror) as err:
_logError("Error reading from file '%s'" % payloadFile)
raise err
finally:
if payload: payload.close()
payloadDataLength = len(payloadData)
payloadSizeData = bitsForInt(payloadDataLength,size=32)
payloadSizeDataLength = len(payloadSizeData)
_logDebug("Payload is %d bits" % payloadDataLength)
_logDebug("That is %f of # of samples" % (float(payloadDataLength)/sampleLength))
# Verify that the payload is reasonably sized
if (payloadDataLength > (sampleLength - 32)):
err = InvalidSize("Payload is too large.")
_logError("Can't embed the payload into the carrier")
raise err
# Embed payload size into first 32 bits of package
for i in xrange(32):
if (samples[i] % 2 != payloadSizeData[i]):
samples[i] += 1
# Embed the payload in the carrier
for i in xrange(payloadDataLength):
if (samples[i+32] % 2 != payloadData[i]):
samples[i+32] += 1
# Write the package to file
wavwrite(outFile,params,stream=samples)
_logInfo("Success!")
def embedSS(carrierFile,payloadFile,outFile):
from amm import wavread,wavwrite
# read in the carrier file
left,right,params = wavread(carrierFile)
sampleRate = params[2]
sampleLength = params[3]*2
# Read the payload in and store it as a list of zeros and ones
payload = None
payloadData = None
try:
payload = open(payloadFile, 'rb')
payloadData = bytesToInts(payload.read())
except (IOerror) as err:
_logError("Error reading from file '%s'" % payloadFile)
raise err
finally:
if payload: payload.close()
payloadSize = len(payloadData)
sizeRatio = (float(payloadSize)/sampleLength)
_logDebug("Payload is %d bits; that is %f%% of carrier size" % (payloadSize, sizeRatio*100))
# verify that the payload is not too large
if (sizeRatio > 0.001):
err = InvalidSize("Payload is too large")
_logError("Can't embed the payload in the carrier")
raise err
# calculate window size
# this is the number of samples that will encode each bit of the payload
# it is 0.1% the number of samples, divided by 2 because left and right echo
# must be the same
windowSize = int(floor(sampleLength*0.001/2))
_logDebug("Using window size of %d samples" % windowSize)
payloadSizeBits = int(floor(log(sampleLength*0.001,2)) - 1)
_logDebug("%d bits needed to encode size of payload" % payloadSizeBits)
payloadData = bitsForInt(len(payloadData),size=payloadSizeBits) + payloadData
from apm import FFT,iFFT
fftl = FFT(left,windowSize)
fftr = FFT(right,windowSize)
def embed(carrierFile,payloadFile,outFile):
"""Embed a message in the carrier audio using echo coding
Writes the resulting audio data to outFile
Parameters:
carrierFile - the name of the carrier audio file
payloadFile - the name of the payload file
outFile - the file to which the package will be written
"""
from amm import wavread,wavwrite
# read in the carrier file
left,right,params = wavread(carrierFile)
sampleRate = params[2]
sampleLength = params[3]*2
# Read the payload in and store it as a list of zeros and ones
payload = None
payloadData = None
try:
payload = open(payloadFile, 'rb')
payloadData = bytesToInts(payload.read())
except (IOerror) as err:
_logError("Error reading from file '%s'" % payloadFile)
raise err
finally:
if payload: payload.close()
payloadSize = len(payloadData)
sizeRatio = (float(payloadSize)/sampleLength)
_logDebug("Payload is %d bits; that is %f%% of carrier size" % (payloadSize, sizeRatio*100))
# verify that the payload is not too large
if (sizeRatio > 0.001):
err = InvalidSize("Payload is too large")
_logError("Can't embed the payload in the carrier")
raise err
from apm import FFTs,iFFTs
timeStep = 1.0/sampleRate
frequencies = np.fft.fftfreq(WINDOWSIZE,timeStep)
leftFFTs = FFTs(left,WINDOWSIZE,timeStep)
rightFFTs = FFTs(right,WINDOWSIZE,timeStep)
for i in range(len(leftFFTs)):
if payloadData[i % payloadSize] == 1:
freqs = FREQ1
else:
freqs = FREQ0
for f in freqs:
leftFFTs[i][f] = TONE
for i in range(len(rightFFTs)):
if payloadData[i % payloadSize] == 1:
freqs = FREQ1
else:
freqs = FREQ0
for f in freqs:
rightFFTs[i][f] = TONE
