Java GUI for encoding video using Mencoder/Mplayer Logo

Frequently Asked Questions: (or might be if they were asked..)

#What software do I need to run this program

#How to I run the program

#mplayer or mencoder dont work properly - what can I do

#Where is the manual

#This program does not run with my version of java, can I recompile it

#How do I get the source code

#Why do I need to change FOURCC

What software do I need to run this program?

The program is java based and a jre (recommend at least java 1.5) is required. Correctly installed executables of mplayer and mencoder are the main requirement. MP4Box and Mkvmerge are required for mp4 and mkv muxing respectively. The locations  for downloading these programs are shown in the links page.

How to I run the program?

Assuming you have downloaded the zip file containing the jar, unzip the archive to it's own folder using an unzipping program and simply execute the jar file. The details are given in the installation page.

mplayer or mencoder don't work properly - what can I do?

This will be either as a result of incorrect configuration or installation of those programs on your system, or as a result of a bug in the front-end. As the author gains more understanding of mplayer commands, this will be reflected in the documentation. mplayer can be tricky to configure when compiling on any platform, so it is better to check mplayer works properly first before using JMencode.

This program requires an executable of mplayer that includes support for png output (for previews).

Where is the manual?

This has not yet been written, but the program is quite simplistic and hopefully when it is fully usable, it will be straightforward to use.

This program does not run with my version of java, can I recompile it?

This is GPL software and anyone is free to recompile and alter the software as they see fit. It has not been tested on other versions of java than 1.5. So it may not work properly with older versions due to minor code differences, mainly those in the Swing API. It can probably be fixed to work with older versions, but this has not yet been done. The program was built with the netbeans IDE 5.5, and the project files are included with the source to open the source in netbeans. This can be used to rebuild the jar file.

How do I get the source code?

This project's Subversion repository can be checked out through SVN with the following instruction set:

svn co jmencode

Why do I need to change FOURCC?

Generally, you do not need to change this at all. But read below if interested.

(This answer is taken from, in answer to the question - Why do third-party players fail to play MPEG-4 movies encoded by MEncoder versions later than 1.0pre7?)
 libavcodec, the native MPEG-4 encoding library usually shipped with MEncoder, used to set the FourCC to 'DIVX' when encoding MPEG-4 videos (the FourCC is an AVI tag to identify the software used to encode and the intended software to use for decoding the video). This led many people to think that libavcodec was a DivX encoding library, when in fact it is a completely different MPEG-4 encoding library which implements the MPEG-4 standard much better than DivX does. Therefore, the new default FourCC used by libavcodec is 'FMP4', but you may override this behavior using MEncoder's -ffourcc option. You may also change the FourCC of existing files in the same way:

mencoder input.avi -o output.avi -ovc copy -oac copy -ffourcc XVID

Note that this will set the FourCC to XVID rather than DIVX. This is recommended as DIVX FourCC means DivX4, which is a very basic MPEG-4 codec, whereas DX50 and XVID both mean full MPEG-4 (ASP). Therefore, if you change the FourCC to DIVX, some bad software or hardware players may choke on some advanced features that libavcodec supports, but DivX doesn't; on the other hand XviD is closer to libavcodec in terms of functionality, and is supported by all decent players.
Because of this annoying detail, third-party software may fail to decode video that has been encoded with software based on a recent libavcodec, such as VLC. Modifying the fourcc with 'DX50' or 'XVID', for example, should resolve the problem.



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