mkvalidator 0011TS.mkv 
WRN0C0: First Block for video track #1 in Cluster at 5663321 is not a keyframe
WRN0C0: First Block for video track #1 in Cluster at 14063747 is not a keyframe
WRN0C0: First Block for video track #1 in Cluster at 22504112 is not a keyframe
WRN0C0: First Block for video track #1 in Cluster at 31003740 is not a keyframe
WRN0C0: First Block for video track #1 in Cluster at 39367787 is not a keyframe
WRN0C0: First Block for video track #1 in Cluster at 48174775 is not a keyframe
mkvalidator 0.3.4: the file appears to be valid
	file created with Lavf53.2.0 / Lavf53.2.0