diff options
| -rw-r--r-- | decoders/spdif/pd.py | 96 |
1 files changed, 74 insertions, 22 deletions
diff --git a/decoders/spdif/pd.py b/decoders/spdif/pd.py index 126a027..fa90cb9 100644 --- a/decoders/spdif/pd.py +++ b/decoders/spdif/pd.py @@ -77,6 +77,14 @@ class Decoder(srd.Decoder): self.seen_preamble = False self.last_preamble = 0 + self.bitrate_message_start = 0 + self.bitrate_message_end = 0 + self.frame_counter = 0 + self.frame_start = 0 + self.frame_length = 0 + + self.sampleratetmp = 1 + self.first_one = True self.subframe = [] @@ -88,8 +96,6 @@ class Decoder(srd.Decoder): self.samplerate = value def get_pulse_type(self): - if self.range1 == 0 or self.range2 == 0: - return -1 if self.pulse_width >= self.range2: return 2 elif self.pulse_width >= self.range1: @@ -101,32 +107,54 @@ class Decoder(srd.Decoder): if self.pulse_width != 0: self.clocks.append(self.pulse_width) self.state = 'GET SECOND PULSE WIDTH' + self.puty([2, ['Found width 1: %d' % (self.pulse_width), 'W1: %d' % (self.pulse_width)]]) + self.ss_edge = self.samplenum def find_second_pulse_width(self): if self.pulse_width > (self.clocks[0] * 1.3) or \ - self.pulse_width < (self.clocks[0] * 0.7): + self.pulse_width <= (self.clocks[0] * 0.75): + self.puty([2, ['Found width 2: %d' % (self.pulse_width), 'W2: %d' % (self.pulse_width)]]) self.clocks.append(self.pulse_width) self.state = 'GET THIRD PULSE WIDTH' + else: + self.puty([2, ['Search width 2: %d' % (self.pulse_width), 'SW2: %d' % (self.pulse_width)]]) + self.ss_edge = self.samplenum def find_third_pulse_width(self): if not ((self.pulse_width > (self.clocks[0] * 1.3) or \ - self.pulse_width < (self.clocks[0] * 0.7)) \ + self.pulse_width <= (self.clocks[0] * 0.75)) \ and (self.pulse_width > (self.clocks[1] * 1.3) or \ - self.pulse_width < (self.clocks[1] * 0.7))): + self.pulse_width <= (self.clocks[1] * 0.75))): + self.puty([2, ['Search width 3: %d' % (self.pulse_width), 'SW3: %d' % (self.pulse_width)]]) + self.ss_edge = self.samplenum return + else: + self.puty([2, ['Found width 3: %d' % (self.pulse_width), 'W3: %d' % (self.pulse_width)]]) + self.ss_edge = self.samplenum + # The message of the calculated bitrate should start at this sample + # (right after the synchronisation). + self.bitrate_message_start = self.samplenum 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)) + # Give some feedback during synchronisation and inform if sample rate + # is too low. + if self.clocks[0] <= 3: + self.putx(0, self.samplenum, [0, ['Short pulses detected. Increase sample rate!']]) + raise SamplerateError('Short pulses detected') + else: + self.putx(0, self.samplenum, [0, ['Synchronisation']]) self.ss_edge = 0 - self.puty([0, ['Signal Bitrate: %d Mbit/s (=> %d kHz)' % \ - (spdif_bitrate, (spdif_bitrate/ (2 * 32)))]]) - - clock_period_nsec = 1000000000 / spdif_bitrate + # Mostly, the synchronisation ends with a long pulse because they + # appear rarely. A skip of the next pulse will then prevent a 'M' + # frame to be labeled an unknown preamble for the first decoded frame. + (data,) = self.wait({0: 'e'}) + self.pulse_width = self.samplenum - self.samplenum_prev_edge + self.samplenum_prev_edge = self.samplenum self.last_preamble = self.samplenum # We are done recovering the clock, now let's decode the data stream. @@ -140,24 +168,39 @@ class Decoder(srd.Decoder): if pulse == 2: self.preamble.append(self.get_pulse_type()) self.state = 'DECODE PREAMBLE' - self.ss_edge = self.samplenum - self.pulse_width - 1 + self.ss_edge = self.samplenum - self.pulse_width + # Use the first ten frames to calculate bit rates + if self.frame_counter == 0: + # This is the first preamble to be decoded. Measurement of + # bit rates starts here. + self.frame_start = self.samplenum + # The bit rate message should end here. + self.bitrate_message_end = self.ss_edge + elif self.frame_counter == 10: + self.frame_length = self.samplenum - self.frame_start + # Use section between end of synchronisation and start of + # first preamble to show measured bit rates. + if self.samplerate: + self.putx(self.bitrate_message_start, self.bitrate_message_end,\ + [0, ['Audio samplingrate: %6.2f kHz; Bit rate: %6.3f MBit/s' %\ + ((self.samplerate / 200 / self.frame_length), (self.samplerate / 200 * 64 / 1000 / self.frame_length))]]) + else: + self.putx(self.bitrate_message_start, self.bitrate_message_end, [0, ['No sample rate given']]) + self.frame_counter += 1 return # We've seen a preamble. if pulse == 1 and self.first_one: self.first_one = False - self.subframe.append([pulse, self.samplenum - \ - self.pulse_width - 1, self.samplenum]) + self.subframe.append([pulse, self.samplenum - self.pulse_width, 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.subframe.append([pulse, self.samplenum - self.pulse_width, self.samplenum]) + self.putx(self.samplenum - self.pulse_width, self.samplenum, [2, ['0']]) self.bitcount += 1 if self.bitcount == 28: @@ -222,16 +265,25 @@ class Decoder(srd.Decoder): self.last_preamble = self.samplenum def decode(self): - if not self.samplerate: - raise SamplerateError('Cannot decode without samplerate.') - - # Throw away first detected edge as it might be mangled data. + # Set samplerate to 0 if it is not given. Decoding is still possible. + try: + if self.samplerate != 0: + pass + except: + self.samplerate = 0 + + # Throw away first two edges as it might be mangled data. self.wait({0: 'e'}) + self.wait({0: 'e'}) + self.ss_edge = 0 + self.puty([2, ['Skip']]) + self.ss_edge = self.samplenum + self.samplenum_prev_edge = self.samplenum while True: # Wait for any edge (rising or falling). (data,) = self.wait({0: 'e'}) - self.pulse_width = self.samplenum - self.samplenum_prev_edge - 1 + self.pulse_width = self.samplenum - self.samplenum_prev_edge self.samplenum_prev_edge = self.samplenum if self.state == 'GET FIRST PULSE WIDTH': |