Compressing audio and video files

[cse b]

Lz4 is not much efficient on audio files.

1) But it is efficient , to compress any video files?

2)can lz4 can reduce any audio or video files to half it's file size?

[Yann Collet]

In general, no.
Most Audio and Video files are already compressed.
So you won't be able to squeeze significantly more bytes by using another compression algorithm.

The only major exception if for uncompressed image / video files,

typically when source is synthetic (computer generated, animated picture, etc.)