WARNING: Requested formats are incompatible for merge and will be merged into mkv.

[VirenMohindra]

Make sure you are using the latest version: run youtube-dl --version and ensure your version is 2016.10.02. If it's not read this FAQ entry and update. Issues with outdated version will be rejected.

• I've verified and I assure that I'm running youtube-dl 2016.10.02

Before submitting an issue make sure you have:

• At least skimmed through README and most notably FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones

What is the purpose of your issue?

• Bug report (encountered problems with youtube-dl)
• Site support request (request for adding support for a new site)
• Feature request (request for a new functionality)
• Question
• Other

---

$ youtube-dl -v
[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'-v']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2016.10.02
[debug] Python version 2.7.10 - Darwin-15.6.0-x86_64-i386-64bit
[debug] exe versions: avconv 11.4, avprobe 11.4, ffmpeg 3.1.4, ffprobe 3.1.4
[debug] Proxy map: {}
Usage: youtube-dl [OPTIONS] URL [URL...]

youtube-dl: error: You must provide at least one URL.
Type youtube-dl --help to see a list of all options.

---

WARNING: Requested formats are incompatible for merge and will be merged into mkv.

It seems that whenever I try to download any video from YouTube, it always defaults to .mkv files with some exceptions which are .webm files. I always have to add -f to get .mp4's.

ffmpeg, vlc and youtube-dl are updated to the newest versions.

[dstftw]

See #8816 (comment).