diff options
Diffstat (limited to 'decoders/spdif')
| -rw-r--r-- | decoders/spdif/__init__.py | 27 | ||||
| -rw-r--r-- | decoders/spdif/pd.py | 236 |
2 files changed, 263 insertions, 0 deletions
diff --git a/decoders/spdif/__init__.py b/decoders/spdif/__init__.py new file mode 100644 index 0000000..e53a435 --- /dev/null +++ b/decoders/spdif/__init__.py @@ -0,0 +1,27 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2014 Guenther Wenninger <robin@bitschubbser.org> +## +## This program 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 2 of the License, or +## (at your option) any later version. +## +## This program 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 program; if not, write to the Free Software +## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +## + +''' +S/PDIF (Sony/Philips Digital Interface Format) is a serial bus for +transmitting audio data. +''' + +from .pd import * + diff --git a/decoders/spdif/pd.py b/decoders/spdif/pd.py new file mode 100644 index 0000000..6f92e0e --- /dev/null +++ b/decoders/spdif/pd.py @@ -0,0 +1,236 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2014 Guenther Wenninger <robin@bitschubbser.org> +## +## This program 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 2 of the License, or +## (at your option) any later version. +## +## This program 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 program; if not, write to the Free Software +## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +## + +import sigrokdecode as srd + +class SamplerateError(Exception): + pass + +class Decoder(srd.Decoder): + api_version = 2 + id = 'spdif' + name = 'S/PDIF' + longname = 'Sony/Philips Digital Interface Format' + desc = 'Serial bus for connecting digital audio devices.' + license = 'gplv2+' + inputs = ['logic'] + outputs = ['spdif'] + channels = ( + {'id': 'data', 'name': 'Data', 'desc': 'Data line'}, + ) + annotations = ( + ('bitrate', 'Bitrate / baudrate'), + ('preamble', 'Preamble'), + ('bits', 'Bits'), + ('aux', 'Auxillary-audio-databits'), + ('samples', 'Audio Samples'), + ('validity', 'Data Valid'), + ('subcode', 'Subcode data'), + ('chan_stat', 'Channnel Status'), + ('parity', 'Parity Bit'), + ) + annotation_rows = ( + ('info', 'Info', (0, 1, 3, 5, 6, 7, 8)), + ('bits', 'Bits', (2,)), + ('samples', 'Samples', (4,)), + ) + + def putx(self, ss, es, data): + self.put(ss, es, self.out_ann, data) + + def __init__(self, **kwargs): + self.state = 0 + self.olddata = None + self.ss_edge = None + self.first_edge = True + self.pulse_width = 0 + + self.clocks = [] + self.range1 = 0 + self.range2 = 0 + + self.preamble_state = 0 + self.preamble = [] + self.seen_preamble = False + self.last_preamble = 0 + + self.first_one = True + self.subframe = [] + + def start(self): + self.out_ann = self.register(srd.OUTPUT_ANN) + + def metadata(self, key, value): + if key == srd.SRD_CONF_SAMPLERATE: + self.samplerate = value + + def get_pulse_type(self, pulse): + if self.range1 == 0 or self.range2 == 0: + return -1 + if pulse >= self.range2: + return 2 + elif pulse >= self.range1: + return 0 + else: + return 1 + + def decode(self, ss, es, data): + if not self.samplerate: + raise SamplerateError('Cannot decode without samplerate.') + + for (self.samplenum, pins) in data: + data = pins[0] + + # Initialize first self.olddata with the first sample value. + if self.olddata == None: + self.olddata = data + continue + + # First we need to recover the clock. + if self.olddata == data: + self.pulse_width += 1 + else: + # Found rising or falling edge. + if self.first_edge: + # Throw away first detected edge as it might be mangled data. + self.first_edge = False + self.pulse_width = 0 + else: + if self.state == 0: + # Find first pulse width. + if self.pulse_width != 0: + self.clocks.append(self.pulse_width) + self.state = 1 + + elif self.state == 1: + # Find second pulse width. + if self.pulse_width > (self.clocks[0] * 1.3) or self.pulse_width < (self.clocks[0] * 0.7): + self.clocks.append(self.pulse_width) + self.state = 2 + + elif self.state == 2: + # Find third pulse width. + if (self.pulse_width > (self.clocks[0] * 1.3) or self.pulse_width < (self.clocks[0] * 0.7)) \ + and (self.pulse_width > (self.clocks[1] * 1.3) or self.pulse_width < (self.clocks[1] * 0.7)): + self.clocks.append(self.pulse_width) + self.clocks.sort() + self.range1 = (self.clocks[0] + self.clocks[1]) / 2 + self.range2 = (self.clocks[1] + self.clocks[2]) / 2 + spdif_bitrate = int(self.samplerate / (self.clocks[2] / 1.5)) + self.ss_edge = 0 + + self.putx(self.ss_edge, self.samplenum, [0, \ + ['Signal Bitrate: %d Mbit/s (=> %d kHz)' % \ + (spdif_bitrate, (spdif_bitrate/ (2 * 32)))]]) + + clock_period_nsec = 1000000000 / spdif_bitrate + + self.last_preamble = self.samplenum + # We are done recovering the clock, now let's decode the data stream. + self.state = 3 + + elif self.state == 3: + # Decode the stream. + pulse = self.get_pulse_type(self.pulse_width) + + if self.seen_preamble: + if pulse == 1 and self.first_one: + self.first_one = False + self.subframe.append([pulse, self.samplenum - self.pulse_width - 1, self.samplenum]) + elif pulse == 1 and not self.first_one: + self.subframe[-1][2] = self.samplenum + self.putx(self.subframe[-1][1], self.samplenum, [2, ['1']]) + self.bitcount += 1 + self.first_one = True + else: + self.subframe.append([pulse, self.samplenum - self.pulse_width - 1, self.samplenum]) + self.putx(self.samplenum - self.pulse_width - 1, self.samplenum, [2, ['0']]) + self.bitcount += 1 + + if self.bitcount == 28: + aux_audio_data = self.subframe[0:4] + sam, sam_rot = '', '' + for a in aux_audio_data: + sam = sam + str(a[0]) + sam_rot = str(a[0]) + sam_rot + sample = self.subframe[4:24] + for s in sample: + sam = sam + str(s[0]) + sam_rot = str(s[0]) + sam_rot + validity = self.subframe[24:25] + subcode_data = self.subframe[25:26] + channel_status = self.subframe[26:27] + parity = self.subframe[27:28] + + self.putx(aux_audio_data[0][1], aux_audio_data[3][2], \ + [3, ['Aux 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]]) + self.putx(sample[0][1], sample[19][2], \ + [3, ['Sample 0x%x' % int(sam, 2), '0x%x' % int(sam, 2)]]) + self.putx(aux_audio_data[0][1], sample[19][2], \ + [4, ['Audio 0x%x' % int(sam_rot, 2), '0x%x' % int(sam_rot, 2)]]) + if validity[0][0] == 0: + self.putx(validity[0][1], validity[0][2], [5, ['V']]) + else: + self.putx(validity[0][1], validity[0][2], [5, ['E']]) + self.putx(subcode_data[0][1], subcode_data[0][2], [6, ['S: %d' % subcode_data[0][0]]]) + self.putx(channel_status[0][1], channel_status[0][2], [7, ['C: %d' % channel_status[0][0]]]) + self.putx(parity[0][1], parity[0][2], [8, ['P: %d' % parity[0][0]]]) + + self.subframe = [] + self.seen_preamble = False + self.bitcount = 0 + else: + # This is probably the start of a preamble, so go + # ahead and decode it. + if pulse == 2: + self.preamble.append(self.get_pulse_type(self.pulse_width)) + self.state = 4 # Decode a preamble. + self.ss_edge = self.samplenum - self.pulse_width - 1 + + elif self.state == 4: + if self.preamble_state == 0: + self.preamble.append(self.get_pulse_type(self.pulse_width)) + self.preamble_state = 1 + elif self.preamble_state == 1: + self.preamble.append(self.get_pulse_type(self.pulse_width)) + self.preamble_state = 2 + elif self.preamble_state == 2: + self.preamble.append(self.get_pulse_type(self.pulse_width)) + self.preamble_state = 0 + self.state = 3 + if self.preamble == [2, 0, 1, 0]: + self.putx(self.ss_edge, self.samplenum, [1, ['Preamble W', 'W']]) + elif self.preamble == [2, 2, 1, 1]: + self.putx(self.ss_edge, self.samplenum, [1, ['Preamble M', 'M']]) + elif self.preamble == [2, 1, 1, 2]: + self.putx(self.ss_edge, self.samplenum, [1, ['Preamble B', 'B']]) + else: + self.putx(self.ss_edge, self.samplenum, [1, ['Unknown Preamble', 'Unkown Prea.', 'U']]) + self.preamble = [] + self.seen_preamble = True + self.bitcount = 0 + self.first_one = True + + self.last_preamble = self.samplenum + + self.pulse_width = 0 + + self.olddata = data + |