FASTEST MKV to MP4 REMUX using FFMPEG | Tutorial | Full Guide

There are many ways to remux MKV to MP4, and more people are finding themselves in need of doing this, especially since Adobe removed support for this popular format.
FFMPEG is super simple and powerful, but a little difficult to learn for first time use.

Download the scripts below:

Timestamps
0:00 - Explanation
1:14 - Command
2:41 - Remuxed result
3:47 - Automating

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Everything in this video is my personal opinion and experience, and should not be considered professional advice. Always do your own research and make sure what you're doing is safe.

[VisiV]

Wow, this is seriously the most useful thing I've ever learned from YouTube. I will use this all the time in my editing flow. Thanks.

[TheClearSight]

PERFECT, that is what i missed, this simple map command. And for everybody, if you have SRT subtitles included you need to put an aditional command so that MP4 container can include them its "-c:s mov_text" if you want to remux it correctly back to mkv use "-c:s srt" normaly you could do a remux in mkvtoolnix but mkvtoolnix will not understand the mov_text format in the MP4.

[imrsvhk]

No nonsense. Clear and concise. Incredibly helpful. One of the most useful things I've learned from YT. Thank you!

[webwritingwithmarianne]

Thank you, you saved my life. I'm up at 3 in the morning helping my daughter make a video for school that's due tomorrow and the files are just too big for regular converters and it worked

[Nerdotomy]

This finally got my ffmpeg to work with me, best feeling ever so far

[karenliu]

This video was extremely helpful and easy to follow. What a lifesaver!! Thank you SO much

[RandomPickles]

Could not find tag for codec subrip in stream #2, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:2 --

[vvhothehecks]

Wow this saved so much time, I have to upload to cloud convert then download back which use a lot of time with big files

[secularteejay]

Will this copy an MKV movie file Dolby Vision layer or HDR layer over to mp4? My LG tv only trigger Dolby Vision under an mp4 format but mkv will not. Mkv will trigger HDR however

[cartossin]

I wrote a similar batch file a few years ago; mine can do unlimited numbers of files in batch. Drag MKV to my batch. limitation: they must be in the same folder. I find even with spinning disks, it doesn't take that long to remux a bunch of MKVs:

@echo off

:start
if [%1]==[] goto end
ffmpeg -i %1 -codec copy %1.mp4
shift
goto start

:end
cls
echo Processing complete. You may close this window or
pause

[the-papaw]

I tried using your bat file to test, but I get errors:

[mp4 @ Could not find tag for codec ass in stream #2, codec not currently supported in container
[out#0/mp4 @ Could not write header (incorrect codec parameters ?): Invalid argument
[sost#0:2/copy @ Error initializing output stream:

Any suggestions?

[chirpingbirdy]

Any suggestion on the command if the MKV has True HD audio? Great video by the way. When I try the command I get the following error: "[mp4 @ truehd in MP4 support is experimental, add '-strict -2' if you want to use it.
Could not write header for output file #0 (incorrect codec parameters ?): Experimental feature
Error initializing output stream 0:3 --" I added the -strict -2 command but it also failed. Any help would be great!

[BetaRuz]

insane quality + god's work man thanks for this love u

[realwaldbaer]

you got me with that - thx a lot! Only thing with me is that my obs file cannot be remuxed this way. I get a failure message which prompts me:
"[mp4 @ Could not find tag for codec pcm_s24le in stream #1, codec not currently supported in container. Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument"
Any idea how to proceed now?

[juansaidg]

Really really is very fast, but i've a doubt. I've converted TO MKV a MP4 video file by merging subtitles with the MKVtoolNix which is really fast but only converts to mkv format. After that i've tried to convert this created mkv file to mp4 with with your method and there's an error: Could not find tag for codec subrip in stream #2, codec not currently supported in container. Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument

[darian]

Thank you, this is so incredibly helpful, just subbed!

[aldo]

Thanks a bunch for this! It worked perfectly!

[nathansixteen]

Is there anyway to alter the batch file so that it will convert an entire folder, not just 1 video? I have a lot of files I need to convert and I don't want to have to sit and type them all in manually

[xXFaZePvssylayerXx]

Could not find tag for codec ass in stream #2, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:3 -- why do i always get this error?

[noicerone]

[SOLVED]
*No such file or directory*
what went wrong?
I was entring the whole path of the Mkv video in the cmd Prompt.

I entered only filename.mkv (as instructed in this video)
and it worked!