def createDecoder(freq, channels):
# Just as with the encoder, to create a decoder, we must first
# allocate resources for it. We want Python to be responsible for
# the memory deallocation, and thus Python must be responsible for
# the initial memory allocation.
# The frequency must be passed in as a 32-bit int
freq = opus.opus_int32(freq)
# The number of channels must also be passed in as a 32-bit int
channels = opus.opus_int32(channels)
# Obtain the number of bytes of memory required for the decoder
size = opus.opus_decoder_get_size(channels)
# Allocate the required memory for the decoder
memory = ctypes.create_string_buffer(size)
# Cast the newly-allocated memory as a pointer to a decoder. We
# could also have used opus.od_p as the pointer type, but writing
# it out in full may be clearer.
decoder = ctypes.cast(memory, ctypes.POINTER(opus.OpusDecoder))
# Initialise the decoder
error = opus.opus_decoder_init(decoder, freq, channels)
# Check that there hasn't been an error when initialising the
# decoder
if error != opus.OPUS_OK:
raise Exception("An error occurred while creating the decoder: " +
opus.opus_strerror(error).decode("utf"))
# Return our newly-created decoder
return decoder
def encode_next_frame(source_ptr):
global length_bytes, bytesProcessed, frame_size, frame_sizes, frame_size_index
if bytesProcessed >= length_bytes:
print("WARNING: No more data")
return None
print("Processing frame at source_ptr ", source_ptr.value)
# Check if we have enough source data remaining to process at
# the current frame size
print("length_bytes: ", length_bytes)
print("bytesProcessed: ", bytesProcessed)
print("bytes remaining (length_bytes - bytesProcessed):",
length_bytes - bytesProcessed)
print("frameSizeBytes(frame_size):", frame_size_bytes(frame_size))
while length_bytes - bytesProcessed < frame_size_bytes(frame_size):
print("Warning! Not enough data for frame.")
frame_size_index -= 1
if frame_size_index < 0:
# The data is less than the smallest number of samples
# in a frame. Either we ignore the remaining samples
# and shorten the audio, or we pad the frame with
# zeros and lengthen the audio. We'll take the easy
# option and shorten the audio.
break
frame_size = frame_sizes[frame_size_index]
print("Decreased frame size to ", frame_size)
if frame_size_index < 0:
print("Warning! Ignoring samples at the end of the audio\n" +
"as they do not fit into even the smallest frame.")
# FIXME: This last frame probably isn't correct
return
# Encode the audio
print("Encoding audio")
numBytes = opus.opus_encode(
encoder, ctypes.cast(source_ptr, ctypes.POINTER(opus.opus_int16)),
frame_size, encoded_frame_ptr, max_encoded_frame_bytes)
print("numBytes: ", numBytes)
# Check for any errors during encoding
if numBytes < 0:
raise Exception("Encoder error detected: " +
opus.opus_strerror(numBytes).decode("utf"))
# Move to next position in the buffer: encoder
oldAddress = source_ptr.value
#print("oldAddress:",oldAddress)
deltaBytes = frame_size * source_channels * 2
newAddress = oldAddress + deltaBytes
#print("newAddress:",newAddress)
source_ptr = ctypes.c_void_p(newAddress)
bytesProcessed = source_ptr.value - source_ptr_init.value
return (source_ptr, encoded_frame_ptr, numBytes)
def create_encoder(npBufSource, samples_per_second):
# To create an encoder, we must first allocate resources for it.
# We want Python to be responsible for the memory deallocation,
# and thus Python must be responsible for the initial memory
# allocation.
# Opus can encode both speech and music, and it can automatically
# detect when the source swaps between the two. Here we specify
# automatic detection.
application = opus.OPUS_APPLICATION_AUDIO
# The frequency must be passed in as a 32-bit int
samples_per_second = opus.opus_int32(samples_per_second)
# The number of channels can be obtained from the shape of the
# NumPy array that was passed in as npBufSource
channels = npBufSource.shape[1]
# Obtain the number of bytes of memory required for the encoder
size = opus.opus_encoder_get_size(channels);
# Allocate the required memory for the encoder
memory = ctypes.create_string_buffer(size)
# Cast the newly-allocated memory as a pointer to an encoder. We
# could also have used opus.oe_p as the pointer type, but writing
# it out in full may be clearer.
encoder = ctypes.cast(memory, ctypes.POINTER(opus.OpusEncoder))
# Initialise the encoder
error = opus.opus_encoder_init(
encoder,
samples_per_second,
channels,
application
)
# Check that there hasn't been an error when initialising the
# encoder
if error != opus.OPUS_OK:
raise Exception("An error occurred while creating the encoder: "+
opus.opus_strerror(error).decode("utf"))
# Return our newly-created encoder
return encoder
def datagramReceived(self, encoded_frame, addr):
#print("Received data from", addr)
# TODO: Once we've started receiving data from a given
# address, should we close down this port to other addresses?
# Create a buffer to hold the PCM data
pcm_buf = PCMBufType()
# Get pointer to first element of the PCM buffer
pcm_buf_ptr = ctypes.cast(pcm_buf, ctypes.POINTER(opus.opus_int16))
# Get pointer to encoded frame
encoded_frame_ptr = ctypes.cast(encoded_frame, ctypes.POINTER(ctypes.c_ubyte))
encoded_frame_bytes = len(encoded_frame)
# Decode the frame
num_samples = opus.opus_decode(
decoder_ptr,
encoded_frame_ptr,
encoded_frame_bytes,
pcm_buf_ptr,
samples_per_channel_in_buf,
0 # FIXME: What's this about?
)
# Check for any errors during decoding
if num_samples < 0:
raise Exception("Decoder error detected: "+
opus.opus_strerror(numSamples).decode("utf"))
# Create a numpy array to hold the decoded PCM data. Note
# that the numpy array has the correct shape (whereas the
# original PCM buffer had sufficient space allocated for the
# largest possible frame.
np_pcm_buf = numpy.ctypeslib.as_array(
pcm_buf,
(num_samples//channels, channels)
)
np_pcm_buf = np_pcm_buf[0:num_samples]
# Put the samples on the queue to play
q.put_nowait(np_pcm_buf)
def datagramReceived(self, data, addr):
print("Received data from", addr)
print("len(data):", len(data))
#print(data)
# Create a buffer to hold the PCM data
buf = TypeBuf()
# Get pointer to first element of buf
bufPtr = ctypes.cast(buf, ctypes.POINTER(opus.opus_int16))
# Get pointer to encoded frame
encodedFramePtr = ctypes.cast(data, ctypes.POINTER(ctypes.c_ubyte))
numBytes = len(data)
# Decode the frame
numSamples = opus.opus_decode(
decoderPtr,
encodedFramePtr,
numBytes,
bufPtr,
samples_per_channel_in_buf,
0 # FIXME: What's this about?
)
print("numSamples: ", numSamples)
# Check for any errors during decoding
if numSamples < 0:
raise Exception("Decoder error detected: " +
opus.opus_strerror(numSamples).decode("utf"))
# Put the samples on the queue to play
np_buf = numpy.ctypeslib.as_array(buf,
(numSamples // channels, channels))
np_buf = np_buf[0:numSamples]
print("data placed on queue")
#print("channels:", channels)
print("shape:", np_buf.shape)
q.put_nowait(np_buf)
def write_opus(self, output_filename):
# Go through the frames and save them as an OggOpus file
# Create a new stream state with a random serial number
stream_state = opus_helpers.create_stream_state()
# Create a packet (reused for each pass)
ogg_packet = ogg.ogg_packet()
# Flag to indicate the start of stream
start_of_stream = 1
# Packet counter
count_packets = 0
# PCM samples counter
count_samples = 0
# Allocate memory for a page
ogg_page = ogg.ogg_page()
# Allocate storage space for the encoded frame. 4,000 bytes
# is the recommended maximum buffer size for the encoded
# frame.
max_bytes_in_encoded_frame = opus.opus_int32(4000)
EncodedFrameType = ctypes.c_ubyte * max_bytes_in_encoded_frame.value
encoded_frame = EncodedFrameType()
# Create a pointer to the first byte of the buffer for the
# encoded frame.
encoded_frame_ptr = ctypes.cast(
ctypes.pointer(encoded_frame),
ctypes.POINTER(ctypes.c_ubyte)
)
# Open file for writing
f = open(output_filename, "wb")
# Headers
# =======
# Specify the identification header
id_header = opus.make_identification_header(
pre_skip = self._pre_skip
)
# Specify the packet containing the identification header
ogg_packet.packet = ctypes.cast(id_header, ogg.c_uchar_p)
ogg_packet.bytes = len(id_header)
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 0
ogg_packet.granulepos = 0
ogg_packet.packetno = count_packets
start_of_stream = 0
count_packets += 1
# Write the header
result = ogg.ogg_stream_packetin(
stream_state,
ogg_packet
)
if result != 0:
raise Exception("Failed to write Opus identification header")
# Specify the comment header
comment_header = opus.make_comment_header()
# Specify the packet containing the identification header
ogg_packet.packet = ctypes.cast(comment_header, ogg.c_uchar_p)
ogg_packet.bytes = len(comment_header)
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 0
ogg_packet.granulepos = 0
ogg_packet.packetno = count_packets
count_packets += 1
# Write the header
result = ogg.ogg_stream_packetin(
stream_state,
ogg_packet
)
if result != 0:
raise Exception("Failed to write Opus comment header")
# Write out pages to file
while ogg.ogg_stream_flush(ctypes.pointer(stream_state),
ctypes.pointer(ogg_page)) != 0:
# Write page
print("Writing header page")
f.write(bytes(ogg_page.header[0:ogg_page.header_len]))
f.write(bytes(ogg_page.body[0:ogg_page.body_len]))
# Frames
# ======
# Loop through the PCM frames in the queue
while not q.empty():
# Get the frame from the queue
frame_pcm = q.get_nowait()
# Convert to opus_int16
frame_pcm = numpy.array(frame_pcm * 2**15, dtype=opus.opus_int16)
# Create a pointer to the start of the frame's data
source_ptr = frame_pcm.ctypes.data_as(ctypes.c_void_p)
#print("Processing frame at sourcePtr ", sourcePtr.value)
# Check if we have enough source data remaining to process at
# the current frame size
samples_per_frame = 960
assert len(frame_pcm) == samples_per_frame
# Encode the audio
#print("Encoding audio")
num_bytes = opus.opus_encode(
self._encoder,
ctypes.cast(source_ptr, ctypes.POINTER(opus.opus_int16)),
samples_per_frame,
encoded_frame_ptr,
max_bytes_in_encoded_frame
)
#print("num_bytes: ", num_bytes)
# Check for any errors during encoding
if num_bytes < 0:
raise Exception("Encoder error detected: "+
opus.opus_strerror(num_bytes).decode("utf"))
# Writing OggOpus
# ===============
# Increase the number of samples
count_samples += samples_per_frame
# Place data into the packet
ogg_packet.packet = encoded_frame_ptr
ogg_packet.bytes = num_bytes
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 0 # FIXME: It needs to end!
ogg_packet.granulepos = count_samples
ogg_packet.packetno = count_packets
# No longer the start of stream
start_of_stream = 0
# Increase the number of packets
count_packets += 1
# Place the packet in to the stream
result = ogg.ogg_stream_packetin(
stream_state,
ogg_packet
)
# Check for errors
if result != 0:
raise Exception("Error while placing packet in Ogg stream")
# Write out pages to file
while ogg.ogg_stream_pageout(ctypes.pointer(stream_state),
ctypes.pointer(ogg_page)) != 0:
# Write page
print("Writing page")
f.write(bytes(ogg_page.header[0:ogg_page.header_len]))
f.write(bytes(ogg_page.body[0:ogg_page.body_len]))
# Force the writing of the final page
while ogg.ogg_stream_flush(ctypes.pointer(stream_state),
ctypes.pointer(ogg_page)) != 0:
# Write page
print("Writing final page")
f.write(bytes(ogg_page.header[0:ogg_page.header_len]))
f.write(bytes(ogg_page.body[0:ogg_page.body_len]))
# Make sure the queue is empty
if not q.empty():
print("WARNING: Failed to completely process all the recorded frames")
# Finished
f.close()
print("Finished writing file")
def process_frame(self, encoded_frame, seq_no):
# Aquire the lock to ensure that we're threadsafe
with self.__lock:
# Mark the fact that we've started
self.__started = True
# Is the sequence number the one we're expecting? If not,
# consider storing it for later processing.
print("Expecting seq no", self.__expected_seq_no)
if encoded_frame is None:
print("Did not get seq no", seq_no)
else:
print("Got seq no", seq_no)
if seq_no != self.__expected_seq_no:
print("Found out of order frame")
# Calculate the new frame's distance from the
# currently expected sequence number. Because the
# sequence numbers may roll over, we need to account
# for that.
distance = JitterBuffer.__calc_distance(
seq_no, self.__expected_seq_no, JitterBuffer.seq_rollover)
# Check if the frame is too late
if distance > 0:
print("Frame is ahead of what we were expecting; storing")
self.__out_of_order_frames[seq_no] = encoded_frame
else:
print("Frame is behind what we were expecting; discarding")
pass
# Are there frames still in the queue? If not, then we
# have a problem. The current frame isn't what we need,
# and we're in immediate need of the one we're missing.
# It's time to give up on the currently expected frame.
if q.empty():
self.give_up_on_expected_sequence()
return
# The encoded frame is the next in the sequence, so process it
# now.
# Create a buffer to hold the PCM data
pcm_buf = self.__PCMFrameBufferType()
# Get pointer to first element of the PCM buffer
pcm_buf_ptr = ctypes.cast(pcm_buf, ctypes.POINTER(opus.opus_int16))
# Get pointer to encoded frame
if encoded_frame is None:
encoded_frame_ptr = None
encoded_frame_bytes = 0
else:
encoded_frame_ptr = ctypes.cast(encoded_frame,
ctypes.POINTER(ctypes.c_ubyte))
encoded_frame_bytes = len(encoded_frame)
# Decode the frame
num_samples = opus.opus_decode(
self.__decoder_ptr,
encoded_frame_ptr,
encoded_frame_bytes,
pcm_buf_ptr,
self.__samples_per_channel_in_buf,
0 # FIXME: What's this about?
)
# Check for any errors during decoding
if num_samples < 0:
raise Exception("Decoder error detected: " +
opus.opus_strerror(numSamples).decode("utf"))
# Create a numpy array to hold the decoded PCM data. Note
# that the numpy array has the correct shape (whereas the
# original PCM buffer had sufficient space allocated for the
# largest possible frame.
np_pcm_buf = numpy.ctypeslib.as_array(
pcm_buf, (num_samples // channels, channels))
np_pcm_buf = np_pcm_buf[0:num_samples]
# Put the samples on the queue to play
q.put_nowait(np_pcm_buf)
# We can now expect the next sequence number
self.__expected_seq_no += 1
# If the next frame is already in the out-of-order dictionary,
# process it now
seq_no = self.__expected_seq_no
if (seq_no in self.__out_of_order_frames):
print("Processing previously stored, out-of-order, frame")
self.process_frame(self.__out_of_order_frames[seq_no], seq_no)
del self.__out_of_order_frames[seq_no]
def encodeThenDecode(npBufSource, npBufTarget, freq):
# Encoding
# ========
# Extract the number of channels in the source
sourceChannels = npBufSource.shape[1]
# Create an encoder
encoder = createEncoder(npBufSource, freq)
# Frame sizes are measured in number of samples. There are only a
# specified number of possible valid frame durations for Opus,
# which (assuming a frequency of 48kHz) gives the following valid
# sizes.
frameSizes = [120, 240, 480, 960, 1920, 2880]
# Specify the desired frame size. This will be used for the vast
# majority of the encoding, except possibly at the end of the
# buffer (as there may not be sufficient data left to fill a
# frame.)
frameSizeIndex = 5
frameSize = frameSizes[frameSizeIndex]
# Function to calculate the size of a frame in bytes
def frameSizeBytes(frameSize):
global bytesPerSample
return frameSize * sourceChannels * bytesPerSample
# Allocate storage space for the encoded frame. 4,000 bytes is
# the recommended maximum buffer size for the encoded frame.
maxEncodedFrameBytes = opus.opus_int32(4000)
encodedFrameType = ctypes.c_ubyte * maxEncodedFrameBytes.value
encodedFrame = encodedFrameType()
# Create a pointer to the first byte of the buffer for the encoded
# frame.
encodedFramePtr = ctypes.cast(ctypes.pointer(encodedFrame),
ctypes.POINTER(ctypes.c_ubyte))
# Number of bytes to process in buffer
bytesPerSample = 2
lengthBytes = buf.shape[0] * buf.shape[1] * bytesPerSample
# Saving
# ======
# Create a new stream state with a random serial number
stream_state = createStreamState()
# Create a packet (reused for each pass)
ogg_packet = ogg.ogg_packet()
# Flag to indicate the start of stream
start_of_stream = 1
# Packet counter
count_packets = 0
# PCM samples counter
count_samples = 0
# Allocate memory for a page
ogg_page = ogg.ogg_page()
# Open file for writing
output_filename = "test.opus"
f = open(output_filename, "wb")
# Specify the identification header
id_header = opus.make_identification_header(pre_skip=312)
# Specify the packet containing the identification header
ogg_packet.packet = ctypes.cast(id_header, ogg.c_uchar_p)
ogg_packet.bytes = len(id_header)
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 0
ogg_packet.granulepos = 0
ogg_packet.packetno = count_packets
start_of_stream = 0
count_packets += 1
# Write the header
result = ogg.ogg_stream_packetin(stream_state, ogg_packet)
if result != 0:
raise Exception("Failed to write Opus identification header")
# Specify the comment header
comment_header = opus.make_comment_header()
# Specify the packet containing the identification header
ogg_packet.packet = ctypes.cast(comment_header, ogg.c_uchar_p)
ogg_packet.bytes = len(comment_header)
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 0
ogg_packet.granulepos = 0
ogg_packet.packetno = count_packets
count_packets += 1
# Write the header
result = ogg.ogg_stream_packetin(stream_state, ogg_packet)
if result != 0:
raise Exception("Failed to write Opus comment header")
# Write out pages to file
while ogg.ogg_stream_flush(ctypes.pointer(stream_state),
ctypes.pointer(ogg_page)) != 0:
# Write page
print("Writing page")
f.write(bytes(ogg_page.header[0:ogg_page.header_len]))
f.write(bytes(ogg_page.body[0:ogg_page.body_len]))
# Decoding
# ========
# Extract the number of channels for the target
targetChannels = npBufTarget.shape[1]
# Create a decoder
decoderFreq = 48000 # TODO: Test changes to this
decoderPtr = createDecoder(decoderFreq, targetChannels)
# Encode and re-decode the audio
# ==============================
# Pointer to a location in the source buffer. We will increment
# this as we progress through the encoding of the buffer. It
# starts pointing to the first byte.
sourcePtr = npBufSource.ctypes.data_as(ctypes.c_void_p)
sourcePtr_init = sourcePtr
# The number of bytes processed will be the difference between the
# pointer's current location and the address of the first byte.
bytesProcessed = sourcePtr.value - sourcePtr_init.value
# Pointer to a location in the target buffer. We will increment
# this as we progress through re-decoding each encoded frame.
targetPtr = npBufTarget.ctypes.data_as(ctypes.c_void_p)
# Loop through the source buffer
while bytesProcessed < lengthBytes:
print("Processing frame at sourcePtr ", sourcePtr.value)
# Check if we have enough source data remaining to process at
# the current frame size
print("lengthBytes: ", lengthBytes)
print("bytesProcessed: ", bytesProcessed)
print("bytes remaining (lengthBytes - bytesProcessed):",
lengthBytes - bytesProcessed)
print("frameSizeBytes(frameSize):", frameSizeBytes(frameSize))
while lengthBytes - bytesProcessed < frameSizeBytes(frameSize):
print("Warning! Not enough data for frame.")
frameSizeIndex -= 1
if frameSizeIndex < 0:
# The data is less than the smallest number of samples
# in a frame. Either we ignore the remaining samples
# and shorten the audio, or we pad the frame with
# zeros and lengthen the audio. We'll take the easy
# option and shorten the audio.
break
frameSize = frameSizes[frameSizeIndex]
print("Decreased frame size to ", frameSize)
if frameSizeIndex < 0:
print("Warning! Ignoring samples at the end of the audio\n" +
"as they do not fit into even the smallest frame.")
break
# Encode the audio
print("Encoding audio")
numBytes = opus.opus_encode(
encoder, ctypes.cast(sourcePtr, ctypes.POINTER(opus.opus_int16)),
frameSize, encodedFramePtr, maxEncodedFrameBytes)
print("numBytes: ", numBytes)
# Check for any errors during encoding
if numBytes < 0:
raise Exception("Encoder error detected: " +
opus.opus_strerror(numBytes).decode("utf"))
# Move to next position in the buffer: encoder
oldAddress = sourcePtr.value
#print("oldAddress:",oldAddress)
deltaBytes = frameSize * sourceChannels * 2
newAddress = oldAddress + deltaBytes
#print("newAddress:",newAddress)
sourcePtr = ctypes.c_void_p(newAddress)
bytesProcessed = sourcePtr.value - sourcePtr_init.value
# Writing OggOpus
# ===============
# Increase the number of samples
count_samples += frameSize
# Place data into the packet
ogg_packet.packet = encodedFramePtr
ogg_packet.bytes = numBytes
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 0 # FIXME: It needs to end!
ogg_packet.granulepos = count_samples
ogg_packet.packetno = count_packets
# No longer the start of stream
start_of_stream = 0
# Increase the number of packets
count_packets += 1
# Place the packet in to the stream
result = ogg.ogg_stream_packetin(stream_state, ogg_packet)
# Check for errors
if result != 0:
raise Exception("Error while placing packet in Ogg stream")
# Write out pages to file
while ogg.ogg_stream_pageout(ctypes.pointer(stream_state),
ctypes.pointer(ogg_page)) != 0:
# Write page
print("Writing page")
f.write(bytes(ogg_page.header[0:ogg_page.header_len]))
f.write(bytes(ogg_page.body[0:ogg_page.body_len]))
# Decode the audio
if True:
print("Decoding audio")
numSamples = opus.opus_decode(
decoderPtr,
encodedFramePtr,
numBytes,
ctypes.cast(targetPtr, ctypes.POINTER(ctypes.c_short)),
5760, # Max space required in PCM
0 # What's this about?
)
print("numSamples: ", numSamples)
# Check for any errors during decoding
if numSamples < 0:
raise Exception("Decoder error detected: " +
opus.opus_strerror(numSamples).decode("utf"))
# Move to next position in the buffer: decoder
targetPtr.value += numSamples * targetChannels * 2
# Write a packet saying we're at the end of the stream
# Place data into the packet
ogg_packet.packet = None
ogg_packet.bytes = 0
ogg_packet.b_o_s = start_of_stream
ogg_packet.e_o_s = 1
ogg_packet.granulepos = count_samples
ogg_packet.packetno = count_packets
# Increase the number of packets
count_packets += 1
# Place the packet in to the stream
#result = ogg.ogg_stream_packetin(
# stream_state,
# ogg_packet
#)
# Check for errors
if result != 0:
raise Exception("Error while placing packet in Ogg stream")
# Write out pages to file
while ogg.ogg_stream_pageout(ctypes.pointer(stream_state),
ctypes.pointer(ogg_page)) != 0:
# Write page
print("Writing page")
f.write(bytes(ogg_page.header[0:ogg_page.header_len]))
f.write(bytes(ogg_page.body[0:ogg_page.body_len]))
# Close file
f.close()
def encodeThenDecode(npBufSource, npBufTarget, freq):
# Encoding
# ========
# Extract the number of channels in the source
sourceChannels = npBufSource.shape[1]
# Create an encoder
encoder = createEncoder(npBufSource, freq)
# Frame sizes are measured in number of samples. There are only a
# specified number of possible valid frame durations for Opus,
# which (assuming a frequency of 48kHz) gives the following valid
# sizes.
frameSizes = [120, 240, 480, 960, 1920, 2880]
# Specify the desired frame size. This will be used for the vast
# majority of the encoding, except possibly at the end of the
# buffer (as there may not be sufficient data left to fill a
# frame.)
frameSizeIndex = 5
frameSize = frameSizes[frameSizeIndex]
# Function to calculate the size of a frame in bytes
def frameSizeBytes(frameSize):
global bytesPerSample
return frameSize * sourceChannels * bytesPerSample
# Allocate storage space for the encoded frame. 4,000 bytes is
# the recommended maximum buffer size for the encoded frame.
maxEncodedFrameBytes = opus.opus_int32(4000)
encodedFrameType = ctypes.c_ubyte * maxEncodedFrameBytes.value
encodedFrame = encodedFrameType()
# Create a pointer to the first byte of the buffer for the encoded
# frame.
encodedFramePtr = ctypes.cast(ctypes.pointer(encodedFrame),
ctypes.POINTER(ctypes.c_ubyte))
# Number of bytes to process in buffer
bytesPerSample = 2
lengthBytes = buf.shape[0] * buf.shape[1] * bytesPerSample
# Decoding
# ========
# Extract the number of channels for the target
targetChannels = npBufTarget.shape[1]
# Create a decoder
decoderFreq = 48000 # TODO: Test changes to this
decoderPtr = createDecoder(decoderFreq, targetChannels)
# Encode and re-decode the audio
# ==============================
# Pointer to a location in the source buffer. We will increment
# this as we progress through the encoding of the buffer. It
# starts pointing to the first byte.
sourcePtr = npBufSource.ctypes.data_as(ctypes.c_void_p)
sourcePtr_init = sourcePtr
# The number of bytes processed will be the difference between the
# pointer's current location and the address of the first byte.
bytesProcessed = sourcePtr.value - sourcePtr_init.value
# Pointer to a location in the target buffer. We will increment
# this as we progress through re-decoding each encoded frame.
targetPtr = npBufTarget.ctypes.data_as(ctypes.c_void_p)
# Loop through the source buffer
count = 0 # FIXME: debugging only
while bytesProcessed < lengthBytes:
print("processing frame: ", count)
count += 1
print("Processing frame at sourcePtr ", sourcePtr.value)
# Check if we have enough source data remaining to process at
# the current frame size
print("lengthBytes: ", lengthBytes)
print("bytesProcessed: ", bytesProcessed)
print("bytes remaining (lengthBytes - bytesProcessed):",
lengthBytes - bytesProcessed)
print("frameSizeBytes(frameSize):", frameSizeBytes(frameSize))
while lengthBytes - bytesProcessed < frameSizeBytes(frameSize):
print("Warning! Not enough data for frame.")
frameSizeIndex -= 1
if frameSizeIndex < 0:
# The data is less than the smallest number of samples
# in a frame. Either we ignore the remaining samples
# and shorten the audio, or we pad the frame with
# zeros and lengthen the audio. We'll take the easy
# option and shorten the audio.
break
frameSize = frameSizes[frameSizeIndex]
print("Decreased frame size to ", frameSize)
if frameSizeIndex < 0:
print("Warning! Ignoring samples at the end of the audio\n" +
"as they do not fit into even the smallest frame.")
break
# Encode the audio
if True:
# Print out the PCM data to see that it's readable
#p = sourcePtr
#d = 0
#while d < frameSize*2*2:
# p2 = ctypes.c_void_p(ctypes.cast(p,ctypes.c_void_p).value + d)
# print("p[",p2.value,"]:",ctypes.cast(p2, opus.opus_int16_p).contents.value)
# d += 2
print("Encoding audio")
numBytes = opus.opus_encode(
encoder, ctypes.cast(sourcePtr,
ctypes.POINTER(opus.opus_int16)),
frameSize, encodedFramePtr, maxEncodedFrameBytes)
print("numBytes: ", numBytes)
# Check for any errors during encoding
if numBytes < 0:
raise Exception("Encoder error detected: " +
opus.opus_strerror(numBytes).decode("utf"))
# Move to next position in the buffer: encoder
oldAddress = sourcePtr.value
#print("oldAddress:",oldAddress)
deltaBytes = frameSize * sourceChannels * 2
newAddress = oldAddress + deltaBytes
#print("newAddress:",newAddress)
sourcePtr = ctypes.c_void_p(newAddress)
bytesProcessed = sourcePtr.value - sourcePtr_init.value
# Decode the audio
if True:
print("Decoding audio")
numSamples = opus.opus_decode(
decoderPtr,
encodedFramePtr,
numBytes,
ctypes.cast(targetPtr, ctypes.POINTER(ctypes.c_short)),
5760, # Max space required in PCM
0 # What's this about?
)
print("numSamples: ", numSamples)
# Check for any errors during decoding
if numSamples < 0:
raise Exception("Decoder error detected: " +
opus.opus_strerror(numSamples).decode("utf"))
# Move to next position in the buffer: decoder
targetPtr.value += numSamples * targetChannels * 2