69 строки
2.1 KiB
Python
Исполняемый файл
69 строки
2.1 KiB
Python
Исполняемый файл
import logging
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from bitarray import bitarray
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from dmr_utils3.bptc import decode_emblc
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from .mmdvm_l1 import DMRPPacketData
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class EmbLCAssembler:
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"""
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This is auxiliary class to assemble a few voice packets and
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assemble embedded LC from them.
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How to use: pass DMRD packets from the same stream id to process_voicedata, if it returns true, then embedded LC can be decoded with decode()
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"""
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VTYPE_N_MAP: dict[DMRPPacketData.VoiceType, int] = {
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DMRPPacketData.VoiceType.BURST_B: 0,
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DMRPPacketData.VoiceType.BURST_C: 1,
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DMRPPacketData.VoiceType.BURST_D: 2,
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DMRPPacketData.VoiceType.BURST_E: 3
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}
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def __init__(self) -> None:
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self.reset()
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def reset(self) -> None:
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self.lcs: list[bytes] = list()
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self.vseq: int = 0
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def process_voicedata(self, p: DMRPPacketData) -> bool:
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if p.voice_type not in EmbLCAssembler.VTYPE_N_MAP:
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return False
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burst_n = EmbLCAssembler.VTYPE_N_MAP[p.voice_type]
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# check voice sequence for next packets
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if burst_n > 0 and p.vseq != (self.vseq + 1) % 0x100:
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logging.error("Embedded LC failed: wrong vseq "
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f"({p.vseq}, expected {self.vseq + 1})")
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self.reset()
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return False
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# check, if burst sequence matches collected
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if len(self.lcs) != burst_n:
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logging.error("Embedded LC failed: wrong burst N "
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f"({burst_n}, expected {len(self.lcs)})")
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self.reset()
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return False
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# try getting LC and collect
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emblc = p.get_emb_lc()
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if emblc is None:
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logging.error("Embedded LC failed: can't get")
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self.reset()
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return False
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self.lcs.append(emblc)
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self.vseq = p.vseq
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# logging.debug(f"assembled emblc's: {self.lcs}")
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return burst_n == 3
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def decode(self) -> bytes|None:
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if len(self.lcs) != 4:
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return None
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emblc_data: bitarray = bitarray(b"".join(self.lcs), endian='big')
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return decode_emblc(emblc_data)
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