decompression or repairing compressed file

[Craig Seeman]

Loss from compression is permanent. The best you can do is prevent further loss by downloading at the highest quality and converting to a lossless or near lossless format.

[Chris Kellam]

Thanks for the reply. Yes but are there any known techniques to reduce the effect?

[Craig Seeman]

That depends on the issues you see. Generally, there’s a quality cost if you’re seeing something like banding and trying to fix it for example.