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#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright 2017 Moritz Luca Schmid, Communications Engineering Lab (CEL) / Karlsruhe Institute of Technology (KIT).
#
# This is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# This software is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this software; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
from gnuradio import gr, blocks
from gnuradio import filter
import gnuradio.dab as grdab
class dabplus_audio_decoder_ff(gr.hier_block2):
"""
Hier block for decoding dab+ audio frames out of whole DAB transmission frame
containing the following blocks:
-msc_decode: extract subchannel and decode it
-firecode checker
-Reed Solomon error repair
-mp4 decoder
See the single blocks for more details
"""
def __init__(self, dab_params, bit_rate, address, subch_size, protection, output_float, verbose=False, debug=False):
if output_float: # map short samples to the range [-1,1] in floats
gr.hier_block2.__init__(self,
"dabplus_audio_decoder_ff",
# Input signature
gr.io_signature(1, 1, gr.sizeof_float * dab_params.num_carriers * 2),
# Output signature
gr.io_signature2(2, 2, gr.sizeof_float, gr.sizeof_float))
else: # output signed 16 bit integers (directly from decoder)
gr.hier_block2.__init__(self,
"dabplus_audio_decoder_ff",
# Input signature
gr.io_signature(1, 1, gr.sizeof_float * dab_params.num_carriers * 2),
# Output signature
gr.io_signature2(2, 2, gr.sizeof_short, gr.sizeof_short))
self.dp = dab_params
self.bit_rate_n = bit_rate / 8
self.address = address
self.size = subch_size
self.protection = protection
self.output_float = output_float
self.verbose = verbose
self.debug = debug
# sanity check
# if self.bit_rate_n*6 != self.size:
# log = gr.logger("log")
# log.debug("bit rate and subchannel size are not fitting")
# log.set_level("ERROR")
# raise ValueError
# MSC decoder extracts logical frames out of transmission frame and decodes it
self.msc_decoder = grdab.msc_decode(self.dp, self.address, self.size, self.protection, self.verbose, self.debug)
# firecode synchronizes to superframes and checks
self.firecode = grdab.firecode_check_bb(int(self.bit_rate_n))
# Reed-Solomon error repair
self.rs = grdab.reed_solomon_decode_bb(int(self.bit_rate_n))
# mp4 decoder
self.mp4 = grdab.mp4_decode_bs(int(self.bit_rate_n))
self.connect((self, 0), self.msc_decoder, self.firecode, self.rs, self.mp4)
if self.output_float:
# map short samples to the range [-1,1] in floats
self.s2f_left = blocks.short_to_float(1, 32767)
self.s2f_right = blocks.short_to_float(1, 32767)
self.gain_left = blocks.multiply_const_ff(1, 1)
self.gain_right = blocks.multiply_const_ff(1, 1)
self.connect((self.mp4, 0), self.s2f_left, self.gain_left, (self, 0))
self.connect((self.mp4, 1), self.s2f_right, self.gain_right, (self, 1))
else:
# output signed 16 bit integers (directly from decoder)
self.connect((self.mp4, 0), (self, 0))
self.connect((self.mp4, 1), (self, 1))
def set_volume(self, volume):
self.gain_left.set_k(volume)
self.gain_right.set_k(volume)
def get_sample_rate(self):
return self.mp4.get_sample_rate()
def get_firecode_passed(self):
return self.firecode.get_firecode_passed()
def get_corrected_errors(self):
return self.rs.get_corrected_errors()
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