How can I convert an M4V file to MP4 without losing quality?

Mac
1

I have several videos saved as M4V files that I need to play on devices and apps that only support MP4. I’m not sure which tools or settings to use so I don’t lose video or audio quality, and I’d also like to avoid watermarks or long export times. What’s the best way to safely convert M4V to MP4 on Windows and Mac?

2

To turn an M4V into an MP4, you are not changing the video itself in most cases, you are swapping the wrapper. The M4V container and MP4 container are close cousins. So if the file is not DRM protected and uses normal codecs, the quality stays the same.

I have done this a bunch of times on both laptops and a cheap Linux box. Here is what has worked for me.

Convert on your computer

On desktop, I usually use one of these:

HandBrake

HandBrake is free and runs on macOS, Windows, and Linux.

What I do:

  • Open HandBrake.
  • Drag the M4V into it.
  • Pick a preset like “Fast 1080p30”.
  • Set the output format to MP4.
  • Hit Start.

If the M4V is already H.264 or H.265 and you pick matching settings, HandBrake sometimes does a near direct copy with minimal changes. If you start tweaking bitrate, filters, or codecs, then you are re-encoding, which can reduce quality.

This is what I use when I want more control over bitrate or compatibility, for example to make a file small enough for an old phone.

Movavi Video Converter and similar apps

There are paid converters that try to keep things simple. Movavi Video Converter is one example.

The basic flow:

  • Add a bunch of M4V files at once.
  • Pick MP4 as output.
  • Choose a preset, like “MP4 H.264 1080p”.
  • Run the batch.

These tools help if you have a folder full of files and you want presets, thumbnails, and a cleaner UI. Handy for bulk work, like converting a whole TV season overnight.

Convert in the browser

If you do not want to install software, online tools are an option. I mostly use these on other people’s machines when I do not want to install anything.

CloudConvert

CloudConvert works straight in the browser.

Steps I use:

This touches someone else’s server, so I avoid using it for private or sensitive videos. For random clips, it works fine.

ezyZip

ezyZip is a bit different. It runs the conversion in your browser, without sending the file off to a remote server, which is better for privacy and big files.
Typical workflow:

  • Open the site.
  • Pick your M4V file.
  • Choose MP4 output.
  • Let it process locally.
  • Save the resulting MP4.

This is faster than server tools on slow internet because the only thing moving is the file on your own disk.

RunConvert.com and similar quick tools

There are minimal converters such as RunConvert.com.
You:

  • Drag the M4V onto the page.
  • Select MP4.
  • Convert.
  • Download the result.

These are good if you want no options, no account, no installer. I use them for quick one-off stuff.

Sometimes you do not need to convert at all

A lot of people convert M4V to MP4 when they do not have to. Modern players already handle both.

Elmedia Player on macOS

Elmedia Player on macOS has worked reliably for me when I was setting up a Mac mini as a video box.

What I liked:

  • Opened both MP4 and M4V with no issues.
  • Subtitles were easy to load and sync.
  • Multiple audio tracks worked fine.
  • Interface is simple, nothing flashy.

Some editions of Elmedia also stream to Smart TVs and let you manage playlists. If all you want is to watch videos without editing them, this avoids the whole conversion step.

VLC Media Player

VLC is the thing I install on every machine first.

Why I keep using it:

  • Plays MP4, M4V, and a ton of other formats.
  • No extra codec packs needed.
  • Runs on Windows, macOS, Linux, and more.

You open M4V files directly and hit play. Zero conversion in between. It also has options for streaming, transcoding, and filters, but you do not need any of that for simple playback.

MPV

MPV is more minimal and keyboard focused.

Typical use:

  • Install it.
  • Drag MP4 or M4V onto the window or call it from the terminal.
  • Use keyboard shortcuts to control playback.

I ended up using MPV on weaker hardware because it felt lighter. It handled both MP4 and M4V with no trouble.

3 Likes
3

You have three separate issues here: quality, DRM, and tools.

  1. Quality
    M4V and MP4 are almost the same container. If your file uses H.264 or H.265 video and AAC audio, you do not need to re‑encode. You only need to re‑wrap. Re‑wrapping keeps 100 percent of the original quality, no generational loss.

Key point. Any option that says “re‑encode”, “convert codec”, “change bitrate”, or lets you pick a quality slider, will reduce quality a bit. You want “copy” or “stream copy” for video and audio.

  1. DRM problem
    If those M4V files come from iTunes purchases with DRM, you will not get a clean, legal, lossless MP4 out of them using normal tools. That is where a lot of people get stuck. If they are home videos or non‑DRM files, you are fine.

  2. Tools that do lossless container swap
    Since @mikeappsreviewer covered HandBrake and online sites, I will go more low‑level and more “no BS”.

FFmpeg (free, Windows/macOS/Linux)
This does a pure container change.

Example command for lossless M4V to MP4:

ffmpeg -i input.m4v -c copy output.mp4

What this does:

  • “-c copy” tells FFmpeg to copy all streams. No re‑encode.
  • It runs fast because it does not touch the video frames.
  • Quality stays identical. File size stays almost the same.

If audio causes issues on a picky device, try:

ffmpeg -i input.m4v -c:v copy -c:a aac -b:a 192k output.mp4

That keeps video untouched, only re‑encodes audio to AAC. Very minor quality difference in audio, often not audible for normal use.

MP4Box / GPAC
Another container level tool.

Basic usage:

MP4Box -add input.m4v output.mp4

This also re‑wraps without re‑encoding in normal cases.

  1. No need to convert for some apps
    You wrote you need MP4 for some devices and apps. For desktop playback, you often do not.

Elmedia Player on macOS plays M4V and MP4 without conversion. If your issue is only that your default app complains, installing Elmedia Player and opening the M4V directly solves it. Same idea as VLC, but the interface is friendlier for a lot of people.

So, quick paths depending on your goal:

  • Need true MP4 container, same quality, non‑DRM
    Use FFmpeg:
    ffmpeg -i input.m4v -c copy output.mp4

  • Need max compatibility for a picky TV or old phone
    Use FFmpeg and re‑encode only audio or only video if they fail to play. Test the copy version first though.

  • Only want to watch on a Mac
    Install Elmedia Player and open the M4V. No conversion, no quality loss, no waiting.

I slightly disagree with leaning on GUI converters for “no quality loss”. Most presets in those tools re‑encode unless you know where the “copy” options sit. FFmpeg or MP4Box with simple commands remove the guesswork.

4

Short version: you’re mostly doing a container swap, not a “real” conversion, so if you do it right there’s zero quality loss and no watermark nonsense.

A few points that complement what @mikeappsreviewer and @chasseurdetoiles already said:

  1. First, check what you actually have

    • If the M4V plays in VLC, open Tools → Codec Information and look at:
      • Video codec: usually H.264 / AVC or H.265 / HEVC
      • Audio: usually AAC
    • If that’s the case and there’s no DRM, you don’t need to re-encode to get MP4. You just re-wrap it.

  2. DRMed iTunes stuff
    This is the annoying bit. If the M4V came from old iTunes purchases and still has DRM, nothing “clean and legal and lossless” will just spit out a compatible MP4 for you.

    • If they are home-recorded or already DRM-free, then you’re fine.
    • If they are protected, expect either:
      • Not to convert at all, or
      • To get into gray-area tools I’m not going to recommend here.

  3. Avoid unnecessary re-encoding in GUI apps
    I actually disagree a bit with leaning too heavily on presets in GUI converters for “no quality loss.” Most “1080p” or “High quality” presets do re-encode, even if the source is already H.264. That means:

    • Extra time
    • New compression artifacts
    • Larger or smaller file, but never truly identical

    If you insist on using HandBrake or similar:

    • Match the codec (H.264 in / H.264 out)
    • Use “Constant Quality” with a very low RF (18 or lower) if you must re-encode
      But honestly, if your goal is no quality loss, HandBrake is not my first pick. It shines when you actually want to compress or tweak.

  4. “I just want it to play, why is this so painful?”
    Given what you described, there’s a good chance you don’t even need to convert every file:

    • On macOS, a quick win is to install Elmedia Player and just open the M4V files directly. Elmedia Player handles M4V and MP4 side by side, with subtitles and multiple audio tracks, and you skip the whole conversion headache.
    • On other OSes, VLC or MPV do the same kind of thing.

    So if your “MP4 only” restriction is self-imposed (like your default app refuses M4V), just use a player that accepts M4V and you’re done in 10 seconds.

  5. When you really need MP4 for a picky device
    Some smart TVs, older game consoles, or certain mobile apps are annoyingly strict: they’ll only accept .mp4, they freak out at odd audio tracks, etc.

    For those:

    • First try a pure container swap (no re-encode).
    • If it doesn’t play, then minimize what you re-encode. Don’t nuke both video and audio if just the audio is the problem.

  6. What about watermarks?

    • Lossless container swap tools (like the ones already mentioned by others) do not add watermarks by default.
    • Watermarks typically appear in:
      • Free “trial” versions of commercial converters
      • Online “video editors” that want you to upgrade
        If the app proudly says “FREE TRIAL,” assume it wants to tattoo your video unless you pay.

So, practical roadmap for you:

  • If your only real goal is playback on a Mac or laptop:

    • Install Elmedia Player (macOS) and just watch the M4V as-is. Zero conversion, zero quality loss, zero chance of watermarks.

  • If you actually have a hardware device that hard-requires MP4:

    • Do a pure container change first (no re-encode).
    • Test on the device.
    • Only if it fails, selectively re-encode either audio or video, not both, at a sensible bitrate.

That way you avoid both quality loss and the whole “mystery watermark” trap.

5

You do not have to re-encode to get from M4V to MP4, and this is where I slightly part ways with the “just use HandBrake presets” approach that @chasseurdetoiles, @boswandelaar and @mikeappsreviewer leaned on. Presets are great when you actually want to compress or tweak, but they usually re-encode, which is the thing that can hurt quality.

1. Easiest path: skip conversion entirely

If your issue is “my app refuses M4V,” the quickest fix on macOS is simply to install Elmedia Player and play the M4V files as they are.

Pros of Elmedia Player

  • Plays M4V and MP4 directly, so no quality loss at all
  • Handles multiple audio tracks and subtitles cleanly
  • Interface is straightforward, no weird codec packs to chase
  • Can act as an all‑in‑one video hub on a Mac mini or laptop

Cons of Elmedia Player

  • macOS only, so not a solution on Windows or Linux
  • Some advanced features sit behind a paid tier
  • Not as lightweight as super‑minimal players for very old machines

Compared with what @chasseurdetoiles and @boswandelaar described (more conversion‑centric workflows), this “just play it” route is often the most painless if your only goal is watching, not editing or exporting.

2. When you truly need MP4 for a picky device

If you have a TV / console / app that refuses M4V:

  • First try a container swap only with a tool that explicitly supports “copy” for video and audio rather than “re-encode.” The quality will be identical, since you are keeping the same H.264/H.265 + AAC streams and only changing the wrapper.
  • Only if the device still rejects the file do you move to re-encoding, and even then I would re-encode only what breaks compatibility (often the audio track or level/profile of the video), not both streams.

Here is where I slightly disagree with relying much on generic “1080p high quality” presets as @mikeappsreviewer outlined. Those are fine for portability, but they are not ideal if your goal is zero loss. Use them if size/compatibility > purity, not the other way around.

3. DRM reality check

If your M4V files are from older iTunes purchases and still carry DRM, none of the clean, lossless methods are going to magically turn them into a free MP4 you can move everywhere. In that case:

  • Expect either “won’t convert” behavior in most tools
  • Or you end up in a legal / gray zone that is not worth recommending here

Home‑recorded, camera‑created, or DRM‑free store files are fine for the lossless container‑swap path.

4. Where this leaves you practically

  • Want to watch on a Mac: install Elmedia Player and stop converting.
  • Need strict MP4 for a device: perform a container‑only change first, then re-encode as a last resort, and avoid blindly using “high quality” presets if your top priority is preserving the original stream.