Repository: youtube-dl
Issue: Support for online channel M3 on MTVA Archívum (HU)
Labels: site-support-request,Good first issue

<!--

######################################################################
  WARNING!
  IGNORING THE FOLLOWING TEMPLATE WILL RESULT IN ISSUE CLOSED AS INCOMPLETE
######################################################################

-->


## Checklist

<!--
Carefully read and work through this check list in order to prevent the most common mistakes and misuse of youtube-dl:
- First of, make sure you are using the latest version of youtube-dl. Run `youtube-dl --version` and ensure your version is 2019.06.08. If it's not, see https://yt-dl.org/update on how to update. Issues with outdated version will be REJECTED.
- Make sure that all provided video/audio/playlist URLs (if any) are alive and playable in a browser.
- Make sure that site you are requesting is not dedicated to copyright infringement, see https://yt-dl.org/copyright-infringement. youtube-dl does not support such sites. In order for site support request to be accepted all provided example URLs should not violate any copyrights.
- Search the bugtracker for similar site support requests: http://yt-dl.org/search-issues. DO NOT post duplicates.
- Finally, put x into all relevant boxes (like this [x])
-->

- [x] I'm reporting a new site support request
- [x] I've verified that I'm running youtube-dl version **2019.06.08**
- [x] I've checked that all provided URLs are alive and playable in a browser
- [x] I've checked that none of provided URLs violate any copyrights
- [x] I've searched the bugtracker for similar site support requests including closed ones


## Example URLs

<!--
Provide all kinds of example URLs support for which should be included. Replace following example URLs by yours.
-->

- Single video: https://archivum.mtva.hu/m3/M3-R3FOU0FJU2pyWjVhL3NYOGppSXl3ZDBHRnZ6UitFSE4vdDhyNDgwbHpEcz0
- Single video: https://archivum.mtva.hu/m3/M3-czJjVW85bFBxZXJDcnh2QWx3R0JLN1hzeTJ2Ti9rWHZTK2ZSK1h5b1NiUT0


## Description

<!--
Provide any additional information.
If work on your issue requires account credentials please provide them or explain how one can obtain them.
-->

MTVA (Media Services and Support Trust Fund) is Hungary's state-owned national public-service broadcasting organization, and it's the successor of MTV (state television service) and MR (state radio service). Its archives provide paid access to media, but they recently incorporated the public channel M3.
M3 was an archive channel airing old programming from MTVA's archives, but as of June 1, 2019, it stopped airing as a traditional TV station, and became an online station on MTVA's archive site:
https://archivum.mtva.hu/m3/

According to the site, M3 now follows an online airing schedule where there is a currently airing program, and any program in the schedule is available for 2 hours prior and 8 hours after streaming, giving a 10-hour window for people to access and replay a certain program which is on the schedule.
There are (Hungarian) subtitles provided at least for some of the programs.
On the video pages, the titles are displayed like this:
Lejátszóban: (In the player:)
[program title]
[episode title]

The links provided were available and playable at the time of filing this request.
The programs are available without a registration, and I don't know if the site uses georestriction.