Saya membutuhkan aplikasi decompressor untuk file. File ini hasil output dari sebuah alat perekam. Ini mirip reverse engineering, jadi tidak ada panduan yang detail hanya informasi terbatas. Metode compressionnya Huffman dan ada tambahan Hamming encoder.
Yang saya inginkan adalah dibuatkan aplikasi yang bisa decompress file tersebut menjadi file yang formatnya akan saya berikan contohnya juga. Jadi nanti akan saya beri contoh file yang harus didecompress dan juga contoh hasil format output yang diharapkan.
Berikut ini sedikit informasi yang saya dapat bagaimana data direkam, semoga bisa membantu,
a. The incoming bit stream is sampled by the hardware and sent to the bit sync software module. Once the bit sync has locked to the incoming bit rate (equivalent to 64, 128, 256, 512, or 1024 WPS/Word Per Second), the individual bits are passed to the bit packer module. The synchronization process continues for every bit received.
b. The bit packer accumulates the data stream into 12 bit words (the basic unit of the data stream, and passes these words along to the frame sync module. Once frame sync is achieved, the bit packer will align the 12 bit data words to the actual word boundary of the frame structured data.
c. The frame sync module searches the 12 bit data word stream for the frame and subframe markers which define the frame structure of the data. After one full frame of markers has been verified, frame sync is declared. If frame sync is not detected within ten seconds, a fault is reported. Any unsynchronized data continues to be passed through, uncompressed, to the Store Manager Processor for storage in the Memory Unit.
d. Frame synchronized data is passed to the delta compressor module. Initially, a baseline frame is sent to the the Store Manager Processor for storage. The data words from subsequent frames of data are compared to the words in the previous frame to determine the delta, or difference, between sequential frames of data. Compression is accomplished by storing only the encoded delta values from frame to frame.
e. The delta values are encoded using the Huffman encoder module. This is an algorithmic method of converting the delta values to a minimum number of bits that can be packed together for efficient memory utilization.
f. The compressed data is then processed by the page builder module. This module counts packed data words in order to track 64-word “page” units.
g. Finally, the Hamming encoder module adds an error correction code for each page of data. The error correction code enables errors in the stored data stream to be detected following data retrieval. Each word is queued for transfer to the SMP using the Time Division Multiplex bus as it is completed.
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