Splitting MKVs to DVD then re-joining

[smegolas]

Hi,
At the moment I am backing up some movies to DVD. It is primarily for backup rather than playback.

When they are 4.37GB I just burn straight to DVD.

But when they are larger (for example 6.55GB) then usually I split them over two or more DVDs.

I am trying to decide whether to split them using MKVMerge or Winrar.

With MKVMerge I get a playable file on each disc. As I said before I am doing this for backup, but it seems handy to also have a playable movie on the discs.

What I want to know is, if I split a movie into 2 using MKVMerge, burn to DVD, and then later I need to use these backups (if a HDD dies for example), will the re-joined movie be identical to the original?

I did a test and MKVMerge threw up an error
Warning: The track number 2 from the file ****** can probably not be appended correctly to the track number 2 from the file *******
Please make sure that the resulting file plays correctly the whole time.
The author of this program will probably not give support for playback issues with the resulting file.


What are your thoughts? Is something 'lost' or broken in the split/join process?

[setarip_old]

Hi!

For clean/safe/certain splitting and rejoining of .MKVs (and almost anything else), my program of choice (freeware) continues to be "HJ Split"...

[hello_hello]

What's track number 2? An audio track? What type?

I can't say I've ever had a problem splitting files with MKVMerge and then rejoining them, so I guess I'm no help, but maybe there's a type of audio or video stream which doesn't like being split and rejoined which I'm not aware of. Have you tried more than one test file?

Maybe it's time for a Bluray burner? ;) I bought one a while back and I'm really glad I did. 23GB or thereabouts per disc....
After spending so much time back in the good old days splitting files to save over multiple floppies, I vowed "never again".

[smegolas]

What's track number 2? An audio track? What type?

I can't say I've ever had a problem splitting files with MKVMerge and then rejoining them, so I guess I'm no help, but maybe there's a type of audio or video stream which doesn't like being split and rejoined which I'm not aware of. Have you tried more than one test file?

Maybe it's time for a Bluray burner? ;) I bought one a while back and I'm really glad I did. 23GB or thereabouts per disc....

Track 2 is DTS audio.

When I watched the re-joined file, I could detect a very slight stutter around the join point. Almost imperceptible, just like a millisecond of hesitation. It seems watchable but kind of defeats my aim of 'backup' if the rejoined file is not 100% identical to the original.

BluRay burner would be nice, but it is too expensive per GB. Plus i've already got a couple of hundred DVD+R 4.7GB to use.

[somms]

BluRay burner would be nice, but it is too expensive per GB. Plus i've already got a couple of hundred DVD+R 4.7GB to use.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817607025

<$1 per BD-R is pretty common nowadays...

[smegolas]

Where I come from they cost about 3x as much as America. And I don't even have a burner.

Whereas I do have a DVD burner, and a massive stack of DVD+R that i've already purchased.

I don't want to get into a debate about Bluray prices, that was not my intention for this thread. Thanks for the suggestion though.

[hello_hello]

Have you tried splitting it in a different place, or tried splitting another file? Maybe it was just a on-off "glitch" because as I said, I've split MKV files quite a few times (my ex owns an external drive which won't accept files larger than 4GB.... which might be the file system, I can't remember) but I've never had any problem joining them again.
The only time I've had issues joining MKV files is when they have different audio streams or aspect ratios etc, but those files obviously weren't split from a single file in the first place.

Which version of MKVMerge are you using?

[Ghitulescu]

Chances that the split will be at frame limits for all streams is extremely low, virtually impossible. You'll have to get used with it (if using split methods that yield viewable movies) or use binary cuts (like the suggested Winrar or hjsplit) but lose the playback capabilities for the second part (and maybe for the first one too).
However, many movies I have can be fitted into a DVDR by dropping all but the original sound, and removing all extras, menus and so on, with no recompression at all.

[hello_hello]

Chances that the split will be at frame limits for all streams is extremely low, virtually impossible. You'll have to get used with it (if using split methods that yield viewable movies) or use binary cuts (like the suggested Winrar or hjsplit) but lose the playback capabilities for the second part (and maybe for the first one too).

I just split three MKV files which I had residing on my hard drive. I told MKVMerge to split them after 1GB.
The first contained AAC audio, the second AC3 audio and the third, both DTS and AC3 audio. I was then able to rejoin all three using MKVMergeGUI but the third gave me a warning regarding the DTS audio (although it played without any glitches).
I tried another MKV, also containing DTS and AC3 audio. This time I split it twice, once while only keeping the DTS audio and a second time while only keeping the AC3 audio. When rejoining the split containing the DTS audio MKVMergeGUI offered the same warning. When rejoining the split containing the AC3 audio there was once again no warning. Both re-joined files played through their join point without any glitching.

From the above it seems there's a problem splitting and rejoining DTS audio, which is basically why I asked the OP what type of track was giving him the warning message. I guess it's only DTS audio streams which are the culprit, but as I didn't think a common audio stream would cause the problem, I was waiting to see if the OP experienced the same problem with other MKVs before testing it myself. Fortunately your advice prompted me to experiment a little sooner.
Whether not being able to split DTS audio is "normal" or not I have no idea. I rarely keep DTS audio tracks so chances are, I've never tried to split and rejoin one before. For all I know it could be some sort of bug involving just the latest version of MKVToolnix. It might even be an eroneous warning message, given each file I split I could rejoin and it'd play without any glitches.
It might pay the OP to ask about the problem in this thread: http://forum.doom9.org/showthread.php?t=155732

However, many movies I have can be fitted into a DVDR by dropping all but the original sound, and removing all extras, menus and so on, with no recompression at all.

Chances are the OP is backing up HD encodes anyway, and chances are, the MKV files contain no extras or menus and so on. He already stated he's only trying to split the ones which don't fit onto a single DVD-R.

[smegolas]

Chances that the split will be at frame limits for all streams is extremely low, virtually impossible. You'll have to get used with it (if using split methods that yield viewable movies) or use binary cuts (like the suggested Winrar or hjsplit) but lose the playback capabilities for the second part (and maybe for the first one too).
However, many movies I have can be fitted into a DVDR by dropping all but the original sound, and removing all extras, menus and so on, with no recompression at all.

Thanks, that answers my question.

I will use Winrar instead because I am kind of anal about little stutters or glitches.

Thanks everyone for all the discussions.

[hello_hello]

Thanks, that answers my question.

Actually it's probably completely wrong and comes from someone who claims they only stick to "official" formats and therefore probably has little experience working with MKV files.
I assume you missed my previous post? The problem seems to only involve DTS audio. It may be a bug in the latest version of MKVMergeGUI. I posted a link to the MKVToolNix thread so you could ask about the problem there.

[smegolas]

Actually it's probably completely wrong and comes from someone who claims they only stick to "official" formats and therefore probably has little experience working with MKV files.
I assume you missed my previous post? The problem seems to only involve DTS audio. It may be a bug in the latest version of MKVMergeGUI. I posted a link to the MKVToolNix thread so you could ask about the problem there.

I posted there now. Thanks.

[Ghitulescu]

So, your options became quite limited.
If I use MKVMerge to split a file (H.264 video with DTS audio) and then at a later date use MKVMerge to re-join the two parts, is it possible that the joined file is not 100% identical to the original? Maybe some sync information or something is slightly different?
Yes, that is possible.I will use Winrar instead because I am kind of anal about little stutters or glitches.
No matter how many advantages a software has, if it fails the function one requires, it makes no sense to use it.

The backup must be 100% identical to the original. Backuping to MKV (or to Divx for that matter) is a contradiction in terms, as one cannot recreate the original, if this get lost/broken/defective.

If you will use WinRAR, be sure to add some reserve (recovery record, it will make sense only from 5% onwards) and do not use compression at all (use store). Maybe some PAR files, if you have space.

[smegolas]

Yes, I have decided to use winrar for those movies which need to split across multiple discs.

It doesnt have the convenience of being able to watch from the disc but that was only a secondary goal anyway. The primary goal is backup.

Thanks everyone for your contribution.

[hello_hello]

smegolas,
Statements of the obvious regarding the disadvantages of using software which fails to function properly aside, and ignoring irrelevant guesses regarding splitting all streams at frame limits, I'd still hoping the problem caused when splitting/recombining dts streams using the current version of MKVToolNix is some kind of bug which can be fixed. Maybe not in time to save you from have to rar all your encodes in order to split them....

You posted about it in the MKVToolNix thread but only received a reply to the effect it's possible to split and re-join MKVs containing dts streams, I made a follow up post in that thread to see if we can get some clarification regarding why it's causing warning messages.

I guess we'll wait and see.

[hello_hello]

The backup must be 100% identical to the original. Backuping to MKV (or to Divx for that matter) is a contradiction in terms, as one cannot recreate the original, if this get lost/broken/defective.

That's a fairly narrow perspective. Who says the MKV encodes are intended as backups? They may simply have been created as more convenient copies and the OP wishes to make backups of those copies.

Personally, I encode the original disc and as I've no interest in playing discs, the disc becomes the backup. I can use it to recreate a 100% identical copy of the original encode, should my original encode ever get lost or become corrupted.
In fact, if I want to, I can use the disc to create a new encode which is 10% better than my original encode. Many of us have moved on from "industry standards" and the inconvenience of playing video from discs.

[setarip_old]

@smegolas

On the outside chance that you didn't read my earlier post, I'd again suggest that you, in addition to WinRar, try (freeware and troublefree) "HJSplit"...

[hello_hello]

For the record, the author of MKVToolNix says not being able to split and rejoin DTS streams is a bug and asked me to post a bug report to remind him to look at fixing it.

smegolas,
If you prefer to split the files and keep them playable, maybe try an older version of MKVToolnix. With any luck the bug only exists in the current version.