MP4 vs M4V File Extensions

I was curious if anyone had any experiences with .mp4 vs .m4v file extensions.  I had been using Handbrake v0.9.3 to encode my DVD collection into MPEG-4’s.  I was using the Normal/Basic presets and using the .mp4 container.  When Handbrake v0.9.4 came out the MPEG-4 file extension defaulted to .m4v for the Normal preset.

When playing the older .mp4’s I noticed “stuttering” in the video.  I didn’t have large time frames of video/audio sync problems as others are complaining about but it is noticeable and annoying.  When playing the new .m4v’s it appears to be smooth and a great viewing experience.  I originally thought they just fixed or tweaked some things in Handbrake v0.9.4 and I was going to have to live with the .mp4 problems.  However, I tried changing the file extension to .m4v and it seems the “stuttering” problem is fixed.  I would have thought that changing the file extension without re-encoding the video would make no difference, but it appears to.

The only issue I have now is that the .m4v’s won’t fast-forward or rewind, so now I have to pick my poison.  Has anyone else had this experience or am I just seeing things after staring at these videos for too long?

I have used both mp4 and m4v files. Both are good in clarity if encoded well. No stuttering I experienced. In mp4, I noticed audio sync lag if we forward the video. I do a bit rewind, then the problem is fixed. But in m4v, WDTV live refuses to do FF or REW as you correctly observed. Now, I stop downloading m4v files and live with mp4.

I used the “High Profile” preset in the latest version of handbrake to create my .m4v files. They play perfectly on my PS3. On the WD TV Live the videos stutter (video only) in the most annoying way. In both cases the videos are being streamed from my media server.

Luckily the WD TV Live plays .ISO files and .m2ts files perfectly, otherwise I would have returned it.

The prerelease firmware fixes M4V file support (ff/rw work as intended). 

Hold out for the next official release. :slight_smile:

I have been having similar struggles.

My goal is to put all my DVDs on a media share then store them away for safe keeping.  The problem is that I am having a hard time finding a tool or format that works consistently well.  Here is my experience:

  • I have been using DVD Shrink to rip my DVDs to my hard drive but there are only a few of the rips that the WD player will play correctly with the correct audio stream even when I try selecting another audio stream from the WD player Options menu.  Also, it does not recognize the chapters.

  • I tried the suggestion from one of the posts to backup as an ISO file.  I tried this but got the same result as backing it up to Video_TS & Audio_TS

  • I have been using Handbrake to convert the rips to the three formats available with that software.  I have a 52" TV and the Normal settings left the video a little blocky.  I have been using the High Profile setting which has made the blockyness go away but takes forever to do one movie and really makes my machine struggle and makes it hard to multi-task.  Also, saving as an MKV file seems to enable chapter selection from the Options menu where M4V files do not.

  • I have tried other free softwares like MakeMKV etc. that i have found through reading forums but have not had any success with them.

If anyone has any suggestions for the perfect workflow and software (preferrably free software) I would be grateful.

I was having problems playing some MKVs that had 3 audio tracks. (out of sync) on my WD Live.

For some reason the video would play as if was in fast motion.

I converted a few mkvs with to mp4 (m4v extension) with handbrake and I was able to keep the audio tracks, unfortunately the video was re-encoded.

It play good on my WD LIVE, no more out of sync. I changed the ( extension to mp4 and suddenly QuickTime could no longer play the file. I changed back to m4v.



I tried Subler to remux the mkv to mp4, it was much faster thank handbrake (no video re-encoding) It simply changed the container from mkv to mp4 (m4v extension), kept all the audio tracks too.


this file I WAS able to change the extension to mp4 and was still playable by QuickTime. My WD Live played both extensions with no problems at all.