www.makemkv.com

Is it possible to open simultaneously two index.bdmv files (film is divided between two discs), choose the respective tracks, and combine them into one mkv output file?

Within MakeMKV - No.

Using other tools, there are many, and use of the index.bdmv files isn't necessary. Just using mkvtoolnix and adding the two files together will accomplish the main part of it. It's combining the subtitles and timestamps where things get tough.

Thanks for prompt and clear reply.
In such case, this might be feature to be considered for the next makemkv update?

As for mkvtoolnix - if there is a "tricky" part, I better keep two mkv files. Looking for easy to use, intuitive solution to achieve the goal.

I guess this feature must have been asked many times before... so it might not be so easy to implement if it is not there already.

There is no "tricky" part in mkvtoolnix.

• Make sure all media files that you want to combine have the same number of tracks, the same track order and equivalent tracks have the same codec (you can check with mkvtoolnix-gui); if not you may have to remux them first to get rid of additional tracks (they can later be added again)
• Open the first one in mkvtoolnix-gui
• drag and drop the media file you want to add to the tab of the opened video; choose "Append to an existing source file"; alternative right klick on the file in the top window and select "append files"
• if you want to combine more than two media files repeat or add/drag and drop multiple files at once (make sure order is correct)
• optional: edit metadata, deselect tracks, change track order, add additional files (like subtitles audio files etc), ...
• choose file name and destination
• start multiplexing

mkvtoolnix will correctly combine all tracks and the result is one large mkv file with the complete video.
Even the chapters are normally combined correctly and the start times adjusted.

I combined the two parts of the Lord of the Rings Extended editions this way and made my own seamless branching videos (with mkv chapter linking).

Thanks a lot for detailed procedure. I will definitely try.

Just one more question - if I merge two mkv files, I will end up with lower quality of resulting mkv file, right? (because of decompression and repeated compression).

Using mkvtoolnix, there should be no decompression/recompression though.

I followed described procedure (using original index.bdmv files) and it worked perfectly. Thanks a lot for sharing!

Woodstock wrote: ↑

Thu Feb 29, 2024 2:22 pm

Using mkvtoolnix, there should be no decompression/recompression though.

In the end, I managed to follow the mkvtoolnix procedure using original index.bdmv files and ended up with one mkv file exactly as described. And since I used bdmv files, no decompression/recompression was used for sure. Just out of curiosity now - using two mkv files as source, are you sure mkvtoolnix would just stitch the mkv files together without decompression/recompression of whole content?

You can think of an mkv file as a zip container for media files. Zipping and unzipping compresses the files but doesn't change them. If you extract them again they are back to their original state. The matroska container works in a similar way.
mkvtoolnix doesn't re-encode any media file but puts the provided files in the matroska container and adds a bunch of metadata which tells the player what tracks can be found inside the container and how to handle them.
Without re-encode it is necessary that the tracks have the same formats and codecs (as mentioned above), otherwise mkvtoolnix can't stitch them together.

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In some cases mkvtoolnix can stitch together files that have a slightly different format but it is not supported and a warning will inform you that it is possible that the resulting file can't be played correctly.

kinos wrote: ↑

Thu Feb 29, 2024 2:48 pm

Woodstock wrote: ↑

Thu Feb 29, 2024 2:22 pm

Using mkvtoolnix, there should be no decompression/recompression though.

In the end, I managed to follow the mkvtoolnix procedure using original index.bdmv files and ended up with one mkv file exactly as described. And since I used bdmv files, no decompression/recompression was used for sure. Just out of curiosity now - using two mkv files as source, are you sure mkvtoolnix would just stitch the mkv files together without decompression/recompression of whole content?

mkvmerge isn't a transcoder. It's a (re)muxer. If it did transcode, the process would take much longer than it does.