Introduction
I want to combine my separate Minecraft worlds into a single world and it seemed like a relatively easy feat, but as I did research it evolved into the need to make a custom program.
The Struggle
I started by shifting the region files and combining them in one region folder, which seemed like the obvious solution and it almost worked. Note: I've opened the files and it seems entire sectors have their coordinates stored, not entities, hence the terrain itself is spatially mismatched with the region file name.
That led to quite a bit of lag when I opened the client and the regions failed to render. I read up on the Anvil file format and imagined a scheme for reading NBT files. I figured I could manually read out the bytes and edit them, but in my continued research I got conflicting answers as to whether region files are gzipped.
I finished enough code to read some raw bytes, but the byte values didn't come out as I expected.
According to the info I have on NBT files, they all start with a CompoundTag and a CompoundTag starts as a single byte valued as 10, or x0A.
This is where I got my format information: https://minecraft.gamepedia.com/NBT_format
Here's a screenshot of what actually came out:
Note: The class description in the screenshot is not accurate. I just quickly filled in enough to read the bytes, not flesh out the UI function.
I assume these bytes coming out as non-sense is a sign that the file is compressed. I found this as a start to the gzip problem:
http://gnuwin32.sourceforge.net/packages/gzip.htm
I imagine if I could get this installed it would unzip this .mca file and I could read the bytes as expected, but I don't understand the installation instructions. It says use the "Shell Commands, 'configure', 'make' and 'make install'". To me that sounds like Unix, but the file I downloaded is for Windows? There aren't any exe's, but there are quite a few C files. I don't have a C-compiler. . .
Note: I still have not got the gzip software to work.
Post Script
I've seen similar questions asked here, but all of them were either old (2016ish) with dead links to software that used to work, or they were recent and unanswered. I found one specific copy of this question asked 5 months ago, but I had to make an account to comment. Here's the link: How can read Minecraft .mca files so that in python I can extract individual blocks? His question is with regard to a Python implementation. He said he found an NBT library for Python, but it was rejecting his MCA files for being not-gzipped.
I've got a lead on understanding the problem because I have the NBTExplorer source code (see the answer I posted), but I'll have to update on how that pans out. As far as getting my world fixed, I think I have a viable solution now.
If anyone could point me to a finished Java library, with source code, that opens .mca's or a discussion board related to this topic that'd be cool. I'm still also interested in how file compression works, but that's probably outside this question's scope. I realize this isn't directly bug or error related; it's it was moreso that I didn't know what further steps to take to make a code that accomplishes this task.
Update
I found someone else's program to do this and posted it as an answer, but I'd still like to know how the file is converted from bytes to useable info. Using the manual edit method of the answer I posted, I will need at most 241,664 manual edits, so I still need a better solution.
First of: As far as I know there is no more information about "where the chunks are", stored in the region files. There are 32(x direction)*32(z-direction)= 1024 Chunks stored within one region file and each of it has its position of data within the file. So the chunks are just numbered within the file itself and the first 8192 bytes are just about if there is any data about that specific chunk or not, where its found within the file and when it got last updated. Where the complete region (those 1024 Chunks) are positioned within the world can be worked out within the file name where the regions themself are numbered in x and z direction.
So in your case you should be able to rename your region files in a way they stay togehter as they are in the original worlds and you should be able to merge them together.
Second: The NBT Format is not the first thing to look at when you want to decode the data. First of the Region files have their own structure: https://minecraft.gamepedia.com/Region_file_format and when you get to the actual data using Zlib (RFC1950) it's getting complicated...
Anyway if you want further information on how to decode I can give you some information (since the files https://www.rfc-editor.org/rfc/rfc1950.html and https://www.rfc-editor.org/rfc/rfc1951 about Zlib (RFC1950) are written in a hard way to understand - at least it was for me). But theres a point where I myself am struggeling right now which is why I came across this question.
I found an editor!
Now I can edit, but I don't know how the editing works. I haven't learned anything, but I did finally find someone else's editor. Not quite what I wanted because I wanted to know how to do this myself.
Update: To fix a region using this software I have to manually edit 2 fields, for up to 32x32 chunks, and I have 118 regions that I need to fix. **That's 241,664 potential manual edits! This solution is not viable on a reasonable timescale, but it's the best I have so far:
I found this page: https://fileinfo.com/extension/mca
Which linked to this page: https://fileinfo.com/software/nbtexplorer/nbtexplorer
Which linked to this page: https://github.com/jaquadro/NBTExplorer/releases
I installed the software and it automatically linked to the .minecraft folder, here's a screenshot of the GUI:
On the bright side, the application download page also has a download link for the source, so I intend to read that! I've opened two files so far to take a glance and they were not commented at all. They're also written in C# which I have never seen before, but I've heard it's very similar to Java, so maybe I'll learn that language too.
This Java library is quite nice for editing .mca and has some examples of doing so in the README
https://github.com/Querz/NBT
As for how the compression works, chunks can be individually compressed via either gzip or zlib, but in practice are generally all zlib compressed, which is implemented in Java through Inflater and Deflater. One annoying thing about the format for chunk data is it is only prefixed with the size of the compressed buffer, with no info on the size of the uncompressed buffer (so the uncompressed buffer must be estimated to be large enough or multiple buffers can be used to fill until the compressed buffer is completely "inflated").
Related
I am having trouble finding out what these .w files are and how to using them with my Java code: see Assignment1.zip at http://see.stanford.edu/see/materials/icspmcs106a/assignments.aspx
I would post a screenshot of my files, but I don't have enough "reputation points" to post an image on this site--I usually just read answers from others b/c I'm just learning. I can't open these .w files or else I would paste some of their contents in here.
For the past year, I've worked a good amount with Python and C++, but I decided to learn some Java from these free Stanford online lectures: http://see.stanford.edu/see/lecturelist.aspx?coll=824a47e1-135f-4508-a5aa-866adcae1111.
I've looked all over and simply cannot find out what .w files are, and I haven't been able to open them. I realize they're clearly worlds for the graphical robot to move around in, but I can't get the .java & .class files to function with these .w (or "world") files.
I would be happy to post some of my code in here as well, if you want. And I could post an image of the files & folders once I get a good enough reputation.
Could someone please help me?
You seem to be missing the documentation for karel.jar. There is already code for reading and working with these files, in sandford.karel.KarelWorld there is a load(File) method. But you will need to be working with the rest of the classes in the jar file, too, so you'll need to look for documentation (maybe given in the lecture videos?) or you'll have a very frustrating time.
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I've got many, many mp3 files that I would like to merge into a single file. I've used the command line method
copy /b 1.mp3+2.mp3 3.mp3
but it's a pain when there's a lot of them and their namings are inconsistent. The time never seems to come out right either.
David's answer is correct that just concatenating the files will leave ID3 tags scattered inside (although this doesn't normally affect playback, so you can do "copy /b" or on UNIX "cat a.mp3 b.mp3 > combined.mp3" in a pinch).
However, mp3wrap isn't exactly the right tool to just combine multiple MP3s into one "clean" file. Rather than using ID3, it actually inserts its own custom data format in amongst the MP3 frames (the "wrap" part), which causes issues with playback, particularly on iTunes and iPods. Although the file will play back fine if you just let them run from start to finish (because players will skip these is arbitrary non-MPEG bytes) the file duration and bitrate will be reported incorrectly, which breaks seeking. Also, mp3wrap will wipe out all your ID3 metadata, including cover art, and fail to update the VBR header with the correct file length.
mp3cat on its own will produce a good concatenated data file (so, better than mp3wrap), but it also strips ID3 tags and fails to update the VBR header with the correct length of the joined file.
Here's a good explanation of these issues and method (two actually) to combine MP3 files and produce a "clean" final result with original metadata intact -- it's command-line so works on Mac/Linux/BSD etc. It uses:
mp3cat to combine the MPEG data frames only into a continuous file, then
id3cp to copy all metadata over to the combined file, and finally
VBRFix to update the VBR header.
For a Windows GUI tool, take a look at Merge MP3 -- it takes care of everything. (VBRFix also comes in GUI form, but it doesn't do the joining.)
As Thomas Owens pointed out, simply concatenating the files will leave multiple ID3 headers scattered throughout the resulting concatenated file - so the time/bitrate info will be wildly wrong.
You're going to need to use a tool which can combine the audio data for you.
mp3wrap would be ideal for this - it's designed to join together MP3 files, without needing to decode + re-encode the data (which would result in a loss of audio quality) and will also deal with the ID3 tags intelligently.
The resulting file can also be split back into its component parts using the mp3splt tool - mp3wrap adds information to the IDv3 comment to allow this.
Use ffmpeg or a similar tool to convert all of your MP3s into a consistent format, e.g.
ffmpeg -i originalA.mp3 -f mp3 -ab 128kb -ar 44100 -ac 2 intermediateA.mp3
ffmpeg -i originalB.mp3 -f mp3 -ab 128kb -ar 44100 -ac 2 intermediateB.mp3
Then, at runtime, concat your files together:
cat intermediateA.mp3 intermediateB.mp3 > output.mp3
Finally, run them through the tool MP3Val to fix any stream errors without forcing a full re-encode:
mp3val output.mp3 -f -nb
The time problem has to do with the ID3 headers of the MP3 files, which is something your method isn't taking into account as the entire file is copied.
Do you have a language of choice that you want to use or doesn't it matter? That will affect what libraries are available that support the operations you want.
MP3 files have headers you need to respect.
You could ether use a library like Open Source Audio Library Project and write a tool around it.
Or you can use a tool that understands mp3 files like Audacity.
What I really wanted was a GUI to reorder them and output them as one file
Playlist Producer does exactly that, decoding and reencoding them into a combined MP3. It's designed for creating mix tapes or simple podcasts, but you might find it useful.
(Disclosure: I wrote the software, and I profit if you buy the Pro Edition. The Lite edition is a free version with a few limitations).
As David says, mp3wrap is the way to go. However, I found that it didn't fix the audio length header, so iTunes refused to play the whole file even though all the data was there. (I merged three 7-minute files, but it only saw up to the first 7 minutes.)
I dug up this blog post, which explains how to fix this and also how to copy the ID3 tags over from the original files (on its own, mp3wrap deletes your ID3 tags). Or to just copy the tags (using id3cp from id3lib), do:
id3cp original.mp3 new.mp3
I would use Winamp to do this. Create a playlist of files you want to merge into one, select Disk Writer output plugin, choose filename and you're done. The file you will get will be correct MP3 file and you can set bitrate etc.
I'd not heard of mp3wrap before. Looks great. I'm guessing someone's made it into a gui as well somewhere. But, just to respond to the original post, I've written a gui that does the COPY /b method. So, under the covers, nothing new under the sun, but the program is all about making the process less painful if you have a lot of files to merge...AND you don't want to re-encode AND each set of files to merge are the same bitrate. If you have that (and you're on Windows), check out Mp3Merge at: http://www.leighweb.com/david/mp3merge and see if that's what you're looking for.
If you want something free with a simple user interface that makes a completely clean mp3 I recommend MP3 Joiner.
Features:
Strips ID3 data (both ID3v1 and ID3v2.x) and doesn't add it's own (unlike mp3wrap)
Lossless joining (doesn't decode and re-encode the .mp3s). No codecs required.
Simple UI (see below)
Low memory usage (uses streams)
Very fast (compared to mp3wrap)
I wrote it :) - so you can request features and I'll add them.
Links:
MP3 Joiner website: Here
Latest installer: Here
Personally I would use something like mplayer with the audio pass though option eg -oac copy
Instead of using the command line to do
copy /b 1.mp3+2.mp3 3.mp3
you could instead use "The Rename" to rename all the MP3 fragments into a series of names that are in order based on some kind of counter. Then you could just use the same command line format but change it a little to:
copy /b *.mp3 output_name.mp3
That is assuming you ripped all of these fragment MP3's at the same time and they have the same audio settings. Worked great for me when I was converting an Audio book I had in .aa to a single .mp3. I had to burn all the .aa files to 9 CD's then rip all 9 CD's and then I was left with about 90 mp3's. Really a pain in the a55.
alright, after a few hours of searching and reading all over the net, I have broken down and decided to ask for help. I am working to automate many of the more medial and repetitive tasks as work, and stumbled upon AutoIt, I love the tool. anyway, Today's task is the export of a slew of tables and queries from Access 2007 in a few different formats. mostly CSVs some Tab delimited, and a couple of dBase DBFs and DBTs. now none of this is all that difficult and in fact the person who previously held my position created about a hundred Macros in the mdb that export the tables. seems to me that he fell well short of hastening the process as you still have to run each macro. I am looking to create an autoit script that will export the correct tables in the correct format to the correct place with the correct name. doesn't seem like it should be that difficult.
so thus far I have been imagining using ADO to tell Access to export which table in which format and where. but I cannot seem to find the necessary commands needed to do that. I also figured that perhaps, at least with the text based formats (CSV, txt, tab) I could read each record out of a given table or query and then build the text file myself in autoit, not the simplest way of doing it, but it could work. The problem arises when trying to create the dBase file, I haven't a clue where to begin with that.
I am open to using JAVA, AutoIt, PHP, or Perl to accomplish my task.
I should note that I am fairly new to ADO. the syntax in ADO seems to elude me frequently. so, any and all help is appreciated, please refrain from the "Just google it" responses. if you have a link to share, or a resource that you have found helpful please post that as well, I am not allergic to reading or doing research. Sometimes it just makes more sense to ask for help.
Thanks,
Kyle
If you are open to using VBA, you could probably make it work with only a little code and the DoCmd-Object.
To export as CSV, have a look at DoCmd.Transfertext
To export to dBase, have a look at DoCmd.TransferDatabase
If you have questions about using those, just ask in the comments and I will provide more information.
This is a sort of bonkers idea, but if you already know Java, you may be able to get this to work with the JDBC-ODBC bridge. You'll first have to register your particular Access database as a named ODBC data source, as the bridge does not appear to support on-the-fly ODBC. I don't have a Windows machine on hand and don't remember the exact sequence of steps to do that, but it should be available from the ODBC driver manager.
How can I split *.wmv file (using java)?
I tryed simple algorythm like read bytes from wmv file and store first half in one file and other half in another file. But the second becomes non-playable.
As I can see i must add to the second file correct header to allow media-players interpret data correct.
Is it true? How can i do splitting if it is not and where can i find wmv header specification if my assumption is correct?
You won't be helping yourself with any format definitions, since WMV files are handled properly only through the Windows Media Format SDK.
Here is some (very little) info on how to call COM from java: http://www.eggheadcafe.com/software/aspnet/29766681/windows-media-encoder-sdk-java.aspx
Then, go to http://sourceforge.net/projects/windowsmedianet/files/WindowsMediaNetSamples/Dec%202008/
and download the samples, look into WMVSPLIT (I guess that's the name of the sample you should read).
Also, you should know that you will be able to split the files ONLY at CLEAN_POINTs (that's WMV lingo for KEYFRAME).
EDIT:
In fact, I would go, in your shoes, for some windows machine and simple .exe or some other kind of extra-process utility that you will execute from java. My strong belief is that it would be simpler.
And if you don't have a windows machine, you'll have to go through the VLC code to find ASF format parser.
I'm trying to edit configuration file in Java. What I really need to do is to change single line, so reading the whole file and writing it back would be waste of time, since configuration file can be big.
Is there a more efficient way to do this? Except reading in/editing/writing out file. I thouhgt of converting entire file to string, replacing the line I want and writting it back.
I don't know how efficient would that be, can someone give me some other suggestions or the one I mentioned are ok, execution time is important.
I would recommend to use the Preferences API instead. Then on the Windows platform your preferences is stored in the registry. On other platforms the corresponding way to save application preferences is used. See also Preferences API Overview.
How big of a configuration file are we talking here? 1k lines? 10k? 1m lines? If the line you want to edit is the last line, just seek to the start of the line, truncate the file there and write the new one. If it's not... you will need to read it whole and write it again.
Oh, and the 2 options you mention are actually the same (read/edit/write).
On the third hand, I think it's irrelevant (unless you have weird constraints, like a flash storage device which takes too long to write, and has limited write cycles), given the sizes of most config files.