How to decompress JPEG, edit and compress back on the same DQT (quantization table) that was in the original?

Question

C++ / C#

Given: When unpacking from JPEG, in addition to the image itself, you need to get the DQT (quantization table), subsampling parameters, the progressive flag and all other parameters. After that, the edited (programmatically) image must be packed with the same parameters and (most importantly) quantized on the same DQT.
Question: What library will help to implement this at a sufficiently high level of abstraction.
So far I see a solution only on libjpeg. But one jpeglib.h for >1200 lines and the almost complete absence of manuals and examples sharply discourages the desire to dive into all this. I still hope to find a better tool.

Answer 1

this program compresses only modified blocks.
hardly leaves the original table completely, but you never know..
www.betterjpeg.com