MyMediaTools

Convert M4V to 3GP — Free Online Tool

Convert M4V files (Apple's iTunes-compatible MPEG-4 video format) to 3GP, the compact mobile container designed for 3G networks. This tool re-encodes your video using H.264 and AAC at mobile-optimized bitrates, making iTunes content playable on legacy mobile devices and low-bandwidth environments — entirely in your browser.

FFmpeg Command

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Estimated output:

Conversion Complete!

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How It Works

M4V and 3GP are both container formats that can carry H.264 video, but the conversion here is a full re-encode rather than a simple remux. The video stream is re-encoded with H.264 (libx264) at CRF 23, and audio is re-encoded from AAC (typically at iTunes-standard bitrates) down to 64k AAC — a significant reduction suited to 3GP's mobile-first design. A critical step is the scale filter (trunc(iw/2)*2:trunc(ih/2)*2), which ensures the output frame dimensions are divisible by 2, a strict requirement for H.264 encoding in the 3GP container. Metadata features present in M4V — such as chapters, multiple audio tracks, and subtitle tracks — are dropped, as the 3GP format does not support them.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg binary — the open-source multimedia processing engine that powers this conversion both in your browser (via WebAssembly) and on the desktop command line.
-i input.m4v Specifies the input file — your M4V source, which is Apple's MPEG-4 based video container typically used for iTunes downloads and iOS-compatible content.
-c:v libx264 Re-encodes the video stream using the H.264 codec (libx264), which is the standard video codec for 3GP files and ensures broad compatibility with mobile devices that support the 3GP format.
-c:a aac Encodes the audio stream as AAC, re-encoding the iTunes AAC track at the lower bitrate specified by -b:a to suit 3GP's mobile-optimized audio expectations.
-crf 23 Sets the H.264 Constant Rate Factor to 23, which is the default quality level — higher values produce smaller files with lower quality, lower values produce larger files with higher quality. For 3GP's typical mobile screen sizes, CRF 23 is a reasonable starting point.
-b:a 64k Sets the output audio bitrate to 64 kilobits per second — a significant reduction from iTunes M4V's typical 128–256k AAC audio, deliberately chosen to keep 3GP files compact for 3G network transmission and limited device storage.
-vf scale=trunc(iw/2)*2:trunc(ih/2)*2 Applies a video filter that rounds the frame width and height down to the nearest even numbers — a mandatory step for H.264 encoding in the 3GP container, preventing encoding failures when the source M4V has odd pixel dimensions.
output.3gp Specifies the output filename with the .3gp extension, which tells FFmpeg to use the 3GP container format — the mobile multimedia format defined by the Third Generation Partnership Project.

Common Use Cases

  • Making an iTunes movie or TV show purchase (DRM-free M4V) playable on an older 3G-era mobile phone that only supports 3GP playback
  • Reducing the file size of an M4V video for sharing over slow mobile data connections or SMS-based multimedia messaging
  • Archiving iTunes video content in a compact 3GP format for storage on low-capacity legacy devices
  • Preparing educational or training video content in 3GP format for distribution in regions where 3G infrastructure and budget handsets are still common
  • Stripping down an iTunes-sourced M4V to a lightweight 3GP clip for embedding in older mobile web applications that targeted WAP or early smartphone browsers
  • Converting M4V home videos synced from an Apple device into 3GP format required by certain older video editing or multimedia tools on feature phones

Frequently Asked Questions

Yes, some quality loss is expected because this is a lossy-to-lossy re-encode. M4V files from iTunes are typically encoded at high bitrates optimized for TV or computer screens, while 3GP is designed for small mobile screens and limited storage. The CRF 23 setting preserves reasonable visual quality, but the audio drops to 64k AAC, which is noticeable compared to iTunes' typical 128–256k AAC tracks. The quality tradeoff is intentional — 3GP prioritizes small file size over fidelity.
The -vf scale=trunc(iw/2)*2:trunc(ih/2)*2 filter ensures your video's width and height are both divisible by 2, which is a hard requirement for H.264 encoding. If your M4V has an odd pixel dimension (which can happen with certain cropped or non-standard exports), the conversion would fail without this filter. It's safe to leave in — if your dimensions are already even, the filter makes no visible change to the output.
All of these are lost in the conversion. The 3GP container does not support chapters, subtitle tracks, or multiple audio streams. Only the primary video stream and the first (or default) audio track are carried over. If your M4V contained iTunes Extras, forced subtitles, or alternate language audio tracks, those will not appear in the 3GP output.
Yes — replace the 64k value in -b:a 64k with a higher bitrate such as 96k or 128k. For example: ffmpeg -i input.m4v -c:v libx264 -c:a aac -crf 23 -b:a 96k -vf scale=trunc(iw/2)*2:trunc(ih/2)*2 output.3gp. Keep in mind that 3GP was designed for bandwidth-constrained environments, so very high audio bitrates somewhat defeat the format's purpose and will increase file size without improving mobile device compatibility.
No. DRM-protected M4V files (indicated by a .m4v extension and purchased from the iTunes Store before Apple moved to DRM-free distribution) cannot be decoded by FFmpeg or any standard converter. Only DRM-free M4V files — such as personal recordings, DRM-free purchases, or files you've encoded yourself — can be processed. Attempting to convert a protected file will result in an error or a blank video output.
On Linux or macOS, you can use a shell loop: for f in *.m4v; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 64k -vf scale=trunc(iw/2)*2:trunc(ih/2)*2 "${f%.m4v}.3gp"; done. On Windows Command Prompt, use: for %f in (*.m4v) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 64k -vf scale=trunc(iw/2)*2:trunc(ih/2)*2 "%~nf.3gp". This browser-based tool processes one file at a time, so the FFmpeg command is the recommended approach for bulk conversion of large M4V libraries.

Technical Notes

M4V is structurally nearly identical to MP4, and while both formats can carry H.264 video, a direct remux into 3GP is not practical here because the audio bitrate and stream configuration need to be adjusted to fit 3GP's mobile-optimized profile. The 3GP container (standardized by 3GPP for UMTS/3G networks) imposes constraints that iTunes M4V files routinely exceed — including audio bitrate expectations and the single-stream audio model. The libx264 encoder with CRF 23 produces a good balance of quality and file size for mobile screens (typically QCIF or QVGA resolution), but if you're targeting very small displays, lowering the resolution explicitly (e.g., adding scale=320:240) may be worthwhile alongside increasing the CRF value to 28–30 for even smaller files. The MJPEG video codec is technically available in 3GP but is not used here because H.264 provides far superior compression for video content. One important limitation: if your source M4V was encoded with HEVC (H.265), the codec must be re-encoded to H.264 for 3GP compatibility, which this command handles automatically since -c:v libx264 always re-encodes regardless of the source codec.

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