It can convert virtually all video files. WinX HD Video Converter Deluxe is an easy-to-use yet powerful video converter. Converting video to H.264 - the most idea format for playing in KMPlayer - is a higly suggested solution to fix 'KMPlayer can't play MP4 MKV FLV files' issue. Due to different codecs, sometimes you can play one MP4 video but can't play another with KMPlayer. Some may be H.264 MP4 and some are HEVC MP4. Not all MP4 files are encoded with the same video formats. MP4 is a container format storing video, audio and other data like subtitles, still images. Convert the Source Video File to H.264 for KMPlayer The problem that MP4 MKV files cannot be playing on Windows with KMPlayer can be caused by several factors including the lack of required MP4 codec pack, computer settings, the problem of KMPlayer itself, etc, based on which solutions for how to solve 'KMPlayer doesn't play MP4' prob will be divided into three parts.

Although it seemingly supports all video formats, we still fail to play the mainstream formats like MP4, FLV, MKV. KMPlayer (on Wiki) - A highly-praised free media player for Windows which can play a long list of video formats including AVI, ASF, WMV, AVS, FLV, MKV, MOV, 3GP, MP4, MPG, MPEG, DAT, OGM, VOB. Convert Video to KMPLayer Supported Format 3 Feasible Ways to Fix KMPlayer Not Playing MP4 Video

Avs media player donot play subtitles