H264LevelEditor is a free and small tool to edit an H264/AVC encoded video stream and change IDC profile level (see here for detailed info about IDC levels).
Works both on MKV containers and raw H264 streams (*.h264, *.264, *.ts or any other file containing H264 encoded video).
It's a portable software, no need to install it. Edit an H264 / AVC encoded video stream and change IDC profile level.

Video stream/file is edited in-place, which means:
1. fast editing
2. no need to reencode the file (save time)
3. no need to demux, edit and remux streams (save time and HDD space)

To make a long story short, some mediaplayers (like my Samsung C6000 LED TV and Sony PS3) look the video file being played for an header info name AVC profile level; if this level is outstandingest than a supported one they simply refuse to play it, even if they could.

BluRay specifications requires level 4.1, which is supported by all actual HD mediaplayers. Many of the video files you'll find on internet were encoded with an unnecessary high level, like 5.1.

The right way to change AVC level is to reencode the file; this is really time consuming, even if you have a recent CPU.
A quick way is to change some bytes inside the file and make it appear as being encoded with a different level; if you're lucky, changing that 5.1 to 4.1 will make the file playable on your mediaplayer.

If this in-place editing won't work, your last (and only) resource is to reencode the whole file.

Requirements:
* .NET Framework

The license of this software is Freeware, you can free download and free use this video utility software.