Could not unzip dataset

[tuantdang]

Thank you very much for sharing the dataset.
I found It is really interesting to have a try this project.
However, I have an issue with the shared dataset.

After downloading 84 files and joining them into mavd_dataset.tar.gz by using the command: cat mavd_dataset.tar.gz.part-* > mavd_dataset.tar.gz, I could not unzip it even I tried serval options:

1. gzip -d mavd_dataset.tar.gz
   gzip: mavd_dataset.tar.gz: not in gzip format

2. tar -xzvf mavd_dataset.tar.gz
   gzip: stdin: not in gzip format
   tar: Child returned status 1
   tar: Error is not recoverable: exiting now