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The MHDC Working Group falling under the Space Link Services (SLS) Area of the CCSDS, has identified the need to update the Recommended Standard CCSDS-121.0-B-2 “Lossless Data Compression”.

This update is intended to resolve potential ambiguities in the current version of the standard.

The principle for the intended changes, is to minimize the potential impact of resolving these ambiguities on existing implementations and related documents.

Therefore, your collaboration is fundamental in order to obtain a complete survey of the choices done in all the existing implementations.

Please answer the following questions about your implementation before May 6, 2019.

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* 1. How does your implementation behave when the size of the input sequence is not multiple of the block size "J"? 
How can the decoder recover the exact input sequence?

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* 2. When encoding the zero-block option, the "r" blocks between consecutive reference samples are partitioned into one or more segments of "s" blocks. Does your implementation use a fixed value for "s" equal to 64?

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* 3. The reference sample interval, "r", is limited to a maximum value of 4096 blocks. Does your implementation allow values of "r" smaller than "s"?

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* 4. When encoding the zero-block option, the last segment of every reference sample interval "r" can have a size smaller than 64 blocks. Does your implementation use the ROS code at the end of this segment (when more than 4 zero-blocks are present) ?

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* 5. When encoding the zero-block option at the end of the file,  do you use the ROS code for the last "incomplete" segment (when more than 4 zero-blocks are present) ?

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* 6. In your implementation, is it possible to insert a reference sample if a predictor is not present?

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* 7. Does your implementation insert a reference sample every "r" CDSes, or every "r" blocks?
 
Note: When the Zero-Block Option is selected, a single CDS can contain up to 64 blocks of "J" input samples (zero-block FS codeword).

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* 8. Does your implementation insert zero bits up to filling a byte boundary before inserting a new reference sample?

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* 9. Does your implementation use the packet format?

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* 10. Does your implementation use any header format?

0 of 10 answered
 

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