Help Needed: Generating DCT_COEFF_2 Table for MPEG-2 Intra VLC (intra_vlc=1) Support

[syjjx]

First, let me explain why I tried to support MPEG2.
I applied your project to live streaming, but I discovered that modern devices do not support MPEG1 hardware encoding, whereas MPEG2 is supported.
Tests show that MPEG2 hardware encoding can reduce CPU overhead to 10%, which is only 1/10 of the original.
Therefore, I attempted the following modifications to extend support for MPEG2.
I have now preliminarily completed MPEG2 decoding, but I encountered a problem: when intra_vlc=1 in MPEG2 video encoding, which means using the MPEG-2 intra VLC table, and referring to Table-15 in IEC-13818-2, I hoped to generate the corresponding DCT_COEFF_2 table, but my attempt failed.
I'm requesting help; could you please help generate the corresponding DCT_COEFF_2?

[emcodem]

Its probably smarter these days to translate an existing mpeg2 decoder written in C to WASM. Here a working client side mpeg2 decoder in javascript, derived from jsmpeg project: https://github.com/emcodem/mxf.js/tree/main
It has only 2 COEFF tables, B‑14 (ff_mpeg1_vlc_table, "dct_coeff_next") and B‑15 (ff_mpeg2_vlc_table) ,