MKV - Stands for Matroska Video File, is the matroska container format. Nowadays it is the generally video files, as well those containing audio (movies) or video only. MKV is similar in conception to other containers like AVI, MP4 or ASF.
Some famous movies may use mkv format as the following reason:
Its open source software player/tools
Support for almost any codec.
Quality-wise, better GUI for muxing tools and more idiot-proof.
Due to these reasons, MKV format became popular, especially on the movie download websites.
Looking for the way to convert MKV to iPod MP4, you must already have this kind of video files. As the movie downloaded from iTunes are protected and appears in WMV format.
I found a solution guide on ubuntuforums:
First install mkvextract, mkvinfo, MP4Box, hexedit and mplayer
$ sudo apt.-get install mkvtoolnix gpac hexedit mplayer
Then you need neroAacEnc. Unpack linux directory, chmod +x neroAacEnc and copy it to a location of your choice (whitin the path)
I've downloaded Heroes Season 2 episode 11 which as this filename: Heroes_S02E11_720p.mkv (and yes, this is legal in Norway!)
Then you have to find out which tracks contains the audio and video.
$ mkvinfo Heroes_S02E11_720p.mkv
Check out the printout to find the tracks.
(in my mkv file video is on track1 and audio is on track 2. Change the numbers to fit you mkv file)
Then demux the mkvfile by running:
$ mkvextract tracks 1:video.h264 2:audio.ac3
Next to do is to change one byte inside the video.h264.
$ hexedit video.h264
On the first line you should see this number combination:
"67 64 00 33"
change this to:
"67 64 00 29"
press ctrl-s to save and ctrl-z to exit
Then you need to convert audio to aac format.
$ mkfifo audiodump.wav
$ neroAacEnc -ignorelength -q 0.20 -if audiodump.wav -of audio.m4a & mplayer audio.ac3 -vc null -vo null -ao pcm:fast
This may take a couple of minutes.
The only thing left is to mux the video and audio file:
$ MP4Box -add video.h264 -add audio.m4a Heroes_S02E11.mp4
All should be finished within 5 minutes because no video conversion is done.
Sounds complicated! I haven't tried it.
I highly recommend using a MKV to iPod MP4 Converter, such as PQ DVD to iPod Video Converter Suite. It is ranked as NO.1 in Toptenreviews, can convert almost all kinds of the video formats including MKV, AVI, WMV, MPEG, DVD, YouTube etc.
Toptenreviews said:" Each time we tested its output quality, PQ DVD converted video and DVD files with impeccable quality. The video and audio were in sync every time, the picture was clear and the colors were bright and vivid."
Here's our recommended MKV Players for playing .mkv files and .mka files.
o VLC media player - Free cross-platform media player.
o BSPlayer - Windows player for playing back avi/asf/mpeg video files.
o SMPlayer - Multiformat video player that doesn't need codecs.
o FantasyDVD Player - Stylish and well equipped DVD player.
o Media Player Classic - Extremely light-weight media player for Windows.
Source by Rachel Bin Green