diff options
| -rw-r--r-- | decoders/guess_bitrate/pd.py | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/decoders/guess_bitrate/pd.py b/decoders/guess_bitrate/pd.py index 1bccc54..e8390c6 100644 --- a/decoders/guess_bitrate/pd.py +++ b/decoders/guess_bitrate/pd.py @@ -43,8 +43,6 @@ class Decoder(srd.Decoder): def __init__(self): self.ss_edge = None - self.first_transition = True - self.bitwidth = None def start(self): self.out_ann = self.register(srd.OUTPUT_ANN) @@ -57,19 +55,21 @@ class Decoder(srd.Decoder): if not self.samplerate: raise SamplerateError('Cannot decode without samplerate.') + # Get the first edge on the data line. + self.wait({0: 'e'}) + self.ss_edge = self.samplenum + + # Get any subsequent edge on the data line. Get the smallest + # distance between any two transitions, assuming it corresponds + # to one bit time of the respective bitrate of the input stream. + # This heuristics keeps getting better for longer captures. + bitwidth = None while True: - # Wait for any transition/edge on the data line. self.wait({0: 'e'}) - # Get the smallest distance between two transitions - # and use that to calculate the bitrate/baudrate. - if self.first_transition: - self.ss_edge = self.samplenum - self.first_transition = False - else: - b = self.samplenum - self.ss_edge - if self.bitwidth is None or b < self.bitwidth: - self.bitwidth = b - bitrate = int(float(self.samplerate) / float(b)) - self.putx([0, ['%d' % bitrate]]) - self.ss_edge = self.samplenum + b = self.samplenum - self.ss_edge + if bitwidth is None or b < bitwidth: + bitwidth = b + bitrate = int(float(self.samplerate) / float(b)) + self.putx([0, ['%d' % bitrate]]) + self.ss_edge = self.samplenum |