Add ffmpeg4 installation instructions in warnings
NONE
_The documentation is not available anymore as the PR was closed or merged._
2022-10-26T14:26:45Z
https://github.com/huggingface/datasets/pull/5167#issuecomment-1292137036
https://api.github.com/repos/huggingface/datasets/issues/5167
IC_kwDODunzps5NBHJM
https://api.github.com/repos/huggingface/datasets/issues/comments/1292137036/reactions
2022-10-27T09:01:11Z
https://api.github.com/repos/huggingface/datasets/issues/comments/1292137036
https://avatars.githubusercontent.com/u/99929124?v=4
https://api.github.com/users/HuggingFaceDocBuilderDev/events{/privacy}
https://api.github.com/users/HuggingFaceDocBuilderDev/followers
https://api.github.com/users/HuggingFaceDocBuilderDev/following{/other_user}
https://api.github.com/users/HuggingFaceDocBuilderDev/gists{/gist_id}
https://github.com/HuggingFaceDocBuilderDev
HuggingFaceDocBuilderDev
U_kgDOBfTMJA
https://api.github.com/users/HuggingFaceDocBuilderDev/orgs
https://api.github.com/users/HuggingFaceDocBuilderDev/received_events
https://api.github.com/users/HuggingFaceDocBuilderDev/repos
https://api.github.com/users/HuggingFaceDocBuilderDev/starred{/owner}{/repo}
https://api.github.com/users/HuggingFaceDocBuilderDev/subscriptions
User
https://api.github.com/users/HuggingFaceDocBuilderDev
public
MEMBER
To make it warn only once, feel free to use a global counter in python - and if the warning has already been done, you don't do it again
2022-10-26T15:19:13Z
https://github.com/huggingface/datasets/pull/5167#issuecomment-1292212474
https://api.github.com/repos/huggingface/datasets/issues/5167
IC_kwDODunzps5NBZj6
https://api.github.com/repos/huggingface/datasets/issues/comments/1292212474/reactions
2022-10-26T15:19:13Z
https://api.github.com/repos/huggingface/datasets/issues/comments/1292212474
https://avatars.githubusercontent.com/u/42851186?v=4
https://api.github.com/users/lhoestq/events{/privacy}
https://api.github.com/users/lhoestq/followers
https://api.github.com/users/lhoestq/following{/other_user}
https://api.github.com/users/lhoestq/gists{/gist_id}
https://github.com/lhoestq
lhoestq
MDQ6VXNlcjQyODUxMTg2
https://api.github.com/users/lhoestq/orgs
https://api.github.com/users/lhoestq/received_events
https://api.github.com/users/lhoestq/repos
https://api.github.com/users/lhoestq/starred{/owner}{/repo}
https://api.github.com/users/lhoestq/subscriptions
User
https://api.github.com/users/lhoestq
public
CONTRIBUTOR
> Added the same formatting for the error message :)

nice!! thank you! 

> Oh and regarding the warning counter, you can do it in another PR maybe ?

Yes, more warnings is better then no warnings.... I'll merge when the CI passes
2022-10-27T08:50:22Z
https://github.com/huggingface/datasets/pull/5167#issuecomment-1293200548
https://api.github.com/repos/huggingface/datasets/issues/5167
IC_kwDODunzps5NFKyk
https://api.github.com/repos/huggingface/datasets/issues/comments/1293200548/reactions
2022-10-27T08:50:22Z
https://api.github.com/repos/huggingface/datasets/issues/comments/1293200548
https://avatars.githubusercontent.com/u/16348744?v=4
https://api.github.com/users/polinaeterna/events{/privacy}
https://api.github.com/users/polinaeterna/followers
https://api.github.com/users/polinaeterna/following{/other_user}
https://api.github.com/users/polinaeterna/gists{/gist_id}
https://github.com/polinaeterna
polinaeterna
MDQ6VXNlcjE2MzQ4NzQ0
https://api.github.com/users/polinaeterna/orgs
https://api.github.com/users/polinaeterna/received_events
https://api.github.com/users/polinaeterna/repos
https://api.github.com/users/polinaeterna/starred{/owner}{/repo}
https://api.github.com/users/polinaeterna/subscriptions
User
https://api.github.com/users/polinaeterna
public
Adds instructions on how to install `ffmpeg=4` on Linux (relevant for Colab users).

Looks pretty ugly because I didn't find a way to check `ffmpeg` version from python (without `subprocess.call()`; `ctypes.util.find_library` doesn't work`), so the warning is raised on each decoding. Any suggestions on how to make it look nice are welcome!

This is how it looks on Colab:
![image](https://user-images.githubusercontent.com/16348744/198052412-d48018d1-4416-4aa5-9114-f7f9b4af031f.png)
