I got this from another site and it work for me. Just run your file through mkvmerge with compression OFF.If you're posting files that are muxed with MKVMerge, they won't be playable on many players if you're using the default settings of MKVMerge 4.1+. The workaround is to use MKVMerge 4.0 or, in newer versions, turn compression OFF on video and audio tracks. To do this:
1. Select each track (video, audio, and subtitles)
2. Select the Extra Options tab
3. Set the Compression option to "none"
4. Start muxing