[Mp4-tech] the CAVLC code design in MPEG4 (part10)

[yux porchlight.ca]

Thanks a lot!
Have a nice day,
Shaun
> Hello
>
> I think you should refer to the original proposal for these codes and
> perhaps contact the authors if you require further information about the
> motivation for the design:
>
> JVT Document JVT-C028, G.Bjontegaard and K. Lillevold, “Context-Adaptive
> VLC Coding of Coefficients”, Fairfax, VA, May 2002
>
> You can get this document from ftp.imtc-files.org/jvt-experts
>
> Regards
>
> Iain Richardson
>
> -----Original Message-----
> From: yux porchlight.ca [mailto:yux porchlight.ca]
> Sent: 26 November 2023 15:46
> To: Iain Richardson (ensigr)
> Cc: yux porchlight.ca; mp4-tech lists.mpegif.org
> Subject: RE: [Mp4-tech] the CAVLC code design in MPEG4 (part10)
>
>
> Thanks a lot, Richardson,
>
> I have read your tutorial. It is very helpful. The image of what to do to
> implement the code is clear. I am wondering if you could help me with some
> further questions, as how the code is designed as like below. Thanks in
> advance.
>
> 1. How is the context represented while designing the lookup tables?
>
>   I may guess that some empirical distributions are built up
>   for non-zero coefficient in all positions? E.g., p(x1) for
>   the first non-zero quantized coefficient, p(x2) for the second.
>   (The first here is the last one in the zigzag as the coding
>   process is carried on in the inverse order).
>
>   Is this right for the CAVLC design in MPEG4(part10)?
>   If yes, is it possible for me to find a report on this?
>   If no, how is the context represented and formed?
>
> 2. What is the design criterion for these tables? For example,
>   what is the point behind the '0...01x...xs' structure of Level
>   VLC1-6? Or, what is done from the context to code tables?
>
> 3. What is the criterion to determine the table switch threshold
>   for VLC0-6? Or how does it depend on the number of non-zero
>   coefficients in neighbouring blocks?
>
> Thanks again and best regards,
> shaun
>
>
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