Message "this conversion will take time"

[mabel]

VLC for Android sometimes shows me the above message which I can't explain, given the circumstances; no doubt because I do not really know how things work
My setup is as follows. On a (windows10) computer I run a Mediaserver (Plex). I have a TV with a Chromecast dongle (model I). I use VLC on my phone to 'cast' video's from the Mediaserver on my TV screen.
Works just fine for many video's but not for some (e.g. video in 'TS' format). These do play on my phone (kudos for VLC) but when trying to play them over the Chromecast I get the message that the file has to be converted and this will take time and drain my battery. I don't understand: if any conversion is to be done, wouldn't it be done by the Mediaserverver? In what way is my phone involved? How does VLC even know that the file has to be converted for Chromecast (which is true)?
I'd just like to know how it works; thanks for any explanations.
Mabel

[Aza]

Chromecasts only support a some codecs. If VLC detects the file you want to cast is not supported, it will re-encode it to use a format the Chromecast supports. Maybe your plex server is serving your video file without re-encoding them.

[mabel]

Sorry but your answer is not really clear to me. Why would VLC (on my phone) have anything to do with re-encoding when the file is streamed directly from the mediaserver to the Chromecast?
Mabel

[Spike1]

A Mediaserver is a server; it serves (delivers) files on request. VLC is a media player, which knows many media formats, but some of them have to be converted into a format VLC can play.

[mabel]

yes, @Spike1, I get that; but it's not an answer to my question. I already said that VLC can play the file without problem. It's when trying to 'cast' the file that I get the message, which, I'm by now convinced, is just plain wrong.
Mabel

[JEFromCanada]

yes, @Spike1, I get that; but it's not an answer to my question. I already said that VLC can play the file without problem. It's when trying to 'cast' the file that I get the message, which, I'm by now convinced, is just plain wrong.
Mabel

It most definitely is an answer. Chromecast doesn't support all codecs. Chromecast is casting the file, not VLC. If VLC recognizes that the video file is using a codec not supported by Chromecast, VLC converts the video to a codec that is supported by Chromecast. It doesn't matter whether VLC can play it or not. It is Chromecast doing the casting, not VLC.

[mabel]

Hi JEFromCanada,
1. I don't think VLC is actually doing any converting; or if it does it would be rather stupid: what would VLC do with the converted signal? The ChromeCast seeks the file on the mediaserver (Plex in my case), not from VLC on my phone. So this can't work.
2. Lots of confusion about the term 'casting'. I'm not saying I know THE meaning; you can call it what you want. But it seems more logical to say VLC is 'casting' the file to the Chromecast.
Mabel

[mabel]

By the way: The message I mentioned is clearly nonsensical, but it could indicate a deeper problem with the 'casting' technique. Obviously, VLC should not decide by itself whether or not the signal is suiteable for ChromeCast; such an indication should come from the mediaserver (which may or may not be able to deliver the signal in a format understandable for the ChromeCast).
But does it work that way; do the various protocols allow such communications?
Mabel