How to reduce mkv file size

[onlygk]

i got some blu ray rip videos in mkv format. some are sizes about 8GB to 10 GB, some are 1.5 to 2.5 GB. in fact video and audio clarity of all videos are same. is there any way to reduce the file size so that i can save my disk space without losing clarity.

Thanks in advance

[El Heggunte]

i got some blu ray rip videos in mkv format. some are sizes about 8GB to 10 GB, some are 1.5 to 2.5 GB. in fact video and audio clarity of all videos are same. is there any way to reduce the file size so that i can save my disk space without losing clarity.

Thanks in advance

1) Not-So-Seriously:

Learn how to re-encode to HEVC through x265.exe;

OR......

2) Seriously:

Buy external/portable HDDs, also you can store the smaller MKVs on USB sticks and/or DVD-Rs.

[Baldrick]

You will lose quality but you can always try shrink it. Use for example vidcoder, under the video tab set the output file size to around 2gb and convert and see how it looks like. You might get better quality by using advanced x264 presets with for example megui.

Or just get a bigger HDD.

[Hoser Rob]

You can't do it without losing quality ... and the input files are already compressed from the original ... but if you want to make them smaller with minimal loss, downsample to smaller resolution.

Also, you seem to be talking about greasy web dl's. Just because there isn't much difference between the 2Gb and 10Gb files doesn't mean there shouldn't be a difference. Most of those people don't know how to use a video encoder properly. I've seen quite large files that had terrible quality video.

In fact, I've made files like that once or twice.

[yfdcaptain]

Just love the way people put nonsense opinions into their replies, would be nice if people would just answer the question to the best of their knowledge.
1. You can take your original over-sized MKV file and extract the audio, subtitles, & chapters, no need to extract raw video, with MKVextractGUI or MKVextractGUI2, which ever works for you.
2. Take the MKV file into VLC media player and use Convert/Save to reduce the size making it an mp4, don't worry if your audio is out of sync, you will be replacing it with the original.
3. Next you open MKVToolNixGUI and drag your mp4 file to the source file on the Input tab, you uncheck the audio in the bottom box, click +Add source files and add back your original audio file which will be in-sync with your video, you can add your subtitle file as well if you want them.
4. Click on the Output tab and link your Chapter file.
5. Start muxing!
Note: if your file is still too large, you can convert/save in VLC media player and do it all over again. Did I mention all programs used are free public domain?

[Baldrick]

Just love the way people put nonsense opinions into their replies, would be nice if people would just answer the question to the best of their knowledge.
1. You can take your original over-sized MKV file and extract the audio, subtitles, & chapters, no need to extract raw video, with MKVextractGUI or MKVextractGUI2, which ever works for you.
2. Take the MKV file into VLC media player and use Convert/Save to reduce the size making it an mp4, don't worry if your audio is out of sync, you will be replacing it with the original.
3. Next you open MKVToolNixGUI and drag your mp4 file to the source file on the Input tab, you uncheck the audio in the bottom box, click +Add source files and add back your original audio file which will be in-sync with your video, you can add your subtitle file as well if you want them.
4. Click on the Output tab and link your Chapter file.
5. Start muxing!
Note: if your file is still too large, you can convert/save in VLC media player and do it all over again. Did I mention all programs used are free public domain?

Isn't it easier to use VidCoder or Handbrake??? You are doing exact same as using vlc convert/save...you can also replace audio tracks with mkvtoolnixgui after.

ANd this thread is 3 years old....

[yfdcaptain]

After doing a lot of research on how to reduce the size of MKV files, I stumbled onto this thread, so I decided to share how I figured it out myself. In my case, I use an external drive to feed movies to my Visio 4K HD television to watch through it's USB port. The USB port reads FAT32, not exFAT nor NTFS. You cannot write files over 4GB to a FAT32 drive, so I needed them smaller. And no, it would not be easier using Handbrake to reduce an MKV file, unless in your vast knowledge you figured out how to get Handbrake to read an MKV file. The thread may be 3 years old, but someone doing research might just stumble across my answer and appreciate it while doing a Google search.

From the page you linked for VidCoder, I quote: "VidCoder is a very easy to use DVD, Blu-ray and any video file to MP4/MKV video converter. It uses HandBrake as its encoding engine." Again I say, no, it would not be easier using Handbrake to reduce an MKV file, unless in your vast knowledge you figured out how to get Handbrake to read an MKV file.

And BTW, isn't this thread for "How to reduce MKV file size"?

[Kerry56]

What are you talking about? Handbrake and VidCoder accept MKV files as input with no issues whatsoever.

[yfdcaptain]

Most MKV files I have tried in Handbrake has resulted in only a partial video, never encodes the whole video, usually less than an hour of it. The route I use has had no problems.

[Kerry56]

^Then your experience is beyond weird. One of the most common methods of using free tools with commercially made DVD's or Blu Ray is to use MakeMKV to decrypt and rip the movies, then use VidCoder or Handbrake for compression. It is a process I've recommended for many years, with no ill results.

The problem is NOT with the tools.

[pandy]

You can use ffmpeg and convert them to something smaller - CRF=21...23 should work in most of cases (filesize around 4GB) however in difficult cases dual pass may be better approach...

https://trac.ffmpeg.org/wiki/Encode/H.264

Inspect mkv for audio - in most of cases DTS (1536/768kbps) can be replaces by AC3 (384 - 448kbps) without perceived significant difference.

[yfdcaptain]

I was trying not to mention the source of the MKV files, but I am at the mercy of whatever people used to create them when downloaded from Newsgroups! If you understand that statement, you probably know why I sometimes have some difficulty.

[9th_Attempt]

i got some blu ray rip videos in mkv format. some are sizes about 8GB to 10 GB, some are 1.5 to 2.5 GB. in fact video and audio clarity of all videos are same.

No they are not! Before you mess around with 'your' files, install 'media info'. When installing select the option that allows it to appear in the right click menu. After install, right click a 2gb file, look at the video bitrate, and the audio file size (and quality). Then select the 8gb file, and compare. If your saying you could care less about the quality, and want to shrink all files to 2 gb each, follow the above advice. But there is no such thing as reducing file size by 75% with no resulting loss of quality!