Is it possible to remove audio files from an mkv without de-/re-muxing?

[pinkfloydfan]

Hi everyone

I'm going through my mkv collection to get rid of unnecessary audio files. I've been using mkvtoolnix to do this but the whole process takes 60-90 mins per file.

Does anyone know of a quicker way to remove the audio files I want please?

Thanks very much

[video.baba]

Uh?
You're getting rid of audio files, using MKVtoolnix, and it takes 60 to 90 minutes?
Something is seriously wrong with that statement.

MKVtoolnix does not encode/re-encode/transcode. Something is up (wrong) with your statement or system. Please give more details...

[LittleBull]

I just tested to remove audio from a 4GB video file with MKVtoolnix. It took 1 minute.

Some recommendations:
Use different source and target drives.
If using external drives, make sure you use USB3 and not USB2.

[pinkfloydfan]

Hi video.baba / LittleBull

I have a number of 20-30GB movie files. For each one I am not re-encoding them I am just loading the mkv file to the Mulitplexer, deselecting the audio/subtitle files I don't want and then pressing "Start multiplexing". All files are stored on a Synology 1812+ NAS drive connected via gigabit ethernet. I am saving them to the same location

Is that the way you would do it or is there a better way?

Thanks

[Bernix]

Hi,
i think that problem is in trafic. Gigabyte file took about several second on local HDD (writing to same HDD). So better to work locally.
There is some software that do not processing file, just modify header, so it is very fast, you get rid of tracks and subtitles, but they are still physicaly in file, so no change of size itself. Something like jmkvpropedit i think.


Bernix

[pandy]

Agree, download file to your local storage - generally this is data copying so you need to transfer almost twice amount of data from same source over network (WiFi?) It may take a while. It looks like your average copy speed is around 100 - 130 Mbps and this may explain long time for processing.
If you really wish very fast processing use 2 different hard disks - i bet time for processing will be at least 10 - 20 times shorter.

[pinkfloydfan]

Gotcha, so to speed up the process I need to copy the file to my local drive. I suspect though that if I include the time taken to copy the file over and then send the remuxed file back it won't be much different!

I don't suppose if anyone knows whether there is a NAS version of mkvtoolnix so it could work at source?

[sneaker]

Seems possible, albeit a bit complicated.

Quick Google:
https://www.youtube.com/watch?v=ruM3v0wzhA4
https://github.com/jlesage/docker-mkvtoolnix
Don't have Synology so can't help. You're probably better off asking on a board dedicated to Synology.


That said a 1 Gbps connection shouldn't be that slow. 100 MB/s would mean like 6 GB per minute. So the bottleneck is something else and even running mkvtoolnix on the NAS itself could turn out to be very slow unless you can eliminate the bottleneck somehow.

[jagabo]

I'm going through my mkv collection to get rid of unnecessary audio files. I've been using mkvtoolnix to do this but the whole process takes 60-90 mins per file. (20-30GB movie files)

Something is very wrong on your system. MkvToolNix on my system, 20 GB 1080p MKV file remux:

NAS to NAS:       13 minutes
local HD to HD:    7 minutes
local SSD to SSD:  2 minutes

[pandy]

Gotcha, so to speed up the process I need to copy the file to my local drive. I suspect though that if I include the time taken to copy the file over and then send the remuxed file back it won't be much different!

I don't suppose if anyone knows whether there is a NAS version of mkvtoolnix so it could work at source?

It may be different as there is no R/W operations - they may be slower than just Read or just Write - and fact that your NAS using 1Gb connection doesn't mean that it can provide 1Gb - latest Raspberry Pi is equipped with GbE but internally limited to around 300Mbps (and i can imagine that this is not sustained bitrate).

And if mkvtoolnix is open source and CPU architecture from your NAS is supported then you should be able to compile mkvtoolnix for your NAS and run it remotely.

[pinkfloydfan]

Thanks everyone for your contributions, much appreciated. I guess I have some more investigating to do

Enjoy the rest of the weekend