Convert MOV to 3GP — Free Online Tool
Convert MOV files to 3GP format optimized for 3G mobile devices, re-encoding video with H.264 and audio with AAC at mobile-friendly bitrates. This conversion strips Apple's professional container features down to a lean, low-bandwidth format designed for older and budget smartphones.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
MOV is Apple's professional QuickTime container, which commonly holds H.264 or H.265 video alongside high-bitrate AAC audio, plus metadata like chapter markers, multiple audio tracks, and transparency. Converting to 3GP involves active re-encoding of both streams: video is encoded with H.264 (libx264) at CRF 23, and audio is re-encoded to AAC at a conservative 64k bitrate — roughly half the default used in MOV workflows. A scale filter (scale=trunc(iw/2)*2:trunc(ih/2)*2) is applied to ensure pixel dimensions are divisible by 2, which is a hard requirement for H.264 in the 3GP container. Metadata features that MOV supports — such as chapter markers, multiple audio tracks, subtitle streams, and alpha transparency — are all dropped in the process, as 3GP does not support any of them.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. In the browser tool, this runs as FFmpeg.wasm compiled to WebAssembly — no server involved. On your desktop, this calls your locally installed FFmpeg executable. |
-i input.mov
|
Specifies the input file as a MOV container. FFmpeg will detect its internal streams — video codec (e.g. H.264, H.265, ProRes), audio codec (e.g. AAC, FLAC), and any metadata tracks — and use this information to plan the conversion. |
-c:v libx264
|
Re-encodes the video stream using the libx264 H.264 encoder, which is the standard video codec for 3GP. Regardless of what video codec the source MOV used, the output will be H.264, ensuring compatibility with 3G mobile devices. |
-c:a aac
|
Re-encodes the audio stream using FFmpeg's built-in AAC encoder. 3GP's audio options are limited to AAC and MP3; AAC is preferred here as it delivers better quality than MP3 at the low 64k bitrate used for mobile delivery. |
-crf 23
|
Sets the H.264 Constant Rate Factor to 23, the libx264 default, which balances visual quality and file size at a level appropriate for mobile screens. Lower values produce better quality and larger files; higher values increase compression and reduce quality. |
-b:a 64k
|
Sets the AAC audio bitrate to 64 kilobits per second, a deliberately conservative target matching 3GP's design goal of low-bandwidth mobile delivery. This is roughly half the 128k default used in typical MOV export workflows, so audio fidelity will be reduced compared to the source. |
-vf scale=trunc(iw/2)*2:trunc(ih/2)*2
|
Applies a video filter that rounds the output width and height down to the nearest even number. H.264 encoding inside the 3GP container requires both dimensions to be divisible by 2; this filter prevents encoding failures when the source MOV has odd pixel dimensions from cropping or unusual camera sensors. |
output.3gp
|
Specifies the output filename with the .3gp extension, which tells FFmpeg to use the 3GP muxer. The resulting file will conform to the 3GP container specification and be playable on compatible mobile devices and media players. |
Common Use Cases
- Sharing iPhone-recorded MOV footage with contacts whose older or budget Android phones only support 3GP video playback in their native gallery apps
- Preparing tutorial or instructional video clips recorded on a Mac for distribution over slow or metered 3G mobile data connections where file size is critical
- Archiving short video clips from professional editing workflows into a compact format for playback on legacy feature phones or embedded devices that support 3GP
- Compressing MOV screen recordings or webcam captures into small 3GP files for MMS attachment, which often have strict size and codec restrictions on older carrier networks
- Generating mobile-compatible video previews from Apple ProRes or H.265 MOV masters for testing how content appears on low-end mobile hardware
Frequently Asked Questions
Yes, noticeably. MOV files typically carry AAC audio at 128k–256k or even lossless formats like FLAC, while this conversion targets 64k AAC — a bitrate optimized for mobile bandwidth rather than audio fidelity. For speech-based content like interviews or tutorials, 64k AAC is generally acceptable. For music or high-fidelity audio, the reduction will be audible. You can increase the -b:a value in the FFmpeg command (up to 128k, the maximum the tool offers for 3GP) if audio quality matters more than file size.
No. The 3GP format does not support chapter markers, multiple audio tracks, or subtitle streams. During conversion, only the primary video stream and the first audio track are carried over — all other tracks and metadata structures are silently dropped. If you need to preserve chapters or secondary audio, 3GP is not the right output format; consider MP4 instead.
The scale filter (scale=trunc(iw/2)*2:trunc(ih/2)*2) ensures the output video's width and height are both even numbers, which is a strict requirement for H.264 encoding in the 3GP container. If your MOV source has odd pixel dimensions — which can happen with cropped footage or certain camera resolutions — H.264 encoding will fail without this filter. It is safe to leave it in even when dimensions are already even, as it becomes a no-op in that case.
The FFmpeg command in this tool does not resize the video — it preserves the source resolution unless the scale filter has to round a dimension by 1 pixel to make it even. A 4K MOV will produce a 4K 3GP file, which is technically valid but defeats the purpose of the format. If you want to downscale to a typical mobile resolution like 480×270 or 640×360, you can modify the -vf flag locally: for example, -vf scale=640:-2 will scale to 640 pixels wide while preserving aspect ratio with an even height.
You can adapt the displayed command into a shell loop. On macOS or Linux, run: for f in *.mov; 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%.mov}.3gp"; done. On Windows Command Prompt, use: for %f in (*.mov) 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". The browser-based tool processes one file at a time, so the FFmpeg command is particularly valuable for bulk jobs.
Even though both MOV and 3GP can carry H.264 video, a straight stream copy (remux) is not reliable here because 3GP imposes stricter constraints on H.264 profiles and levels than MOV does. MOV files frequently use High Profile H.264, which many 3G devices cannot decode. Re-encoding with libx264 allows FFmpeg to produce a Baseline or Main Profile stream that maximizes compatibility with the target mobile hardware. The trade-off is slightly longer processing time and a second generation of lossy compression on the video.
Technical Notes
The 3GP specification was designed for UMTS (3G) networks and the constrained storage of early 2000s mobile handsets, so its codec support is deliberately narrow: H.264 and MJPEG for video, AAC and MP3 for audio. MOV's broader codec roster — including H.265/HEVC, VP9, FLAC, Opus, and ProRes — has no equivalent in 3GP, meaning any MOV using those codecs requires full transcoding rather than a simple remux. Transparency (alpha channel video using codecs like PNG or Apple Animation in MOV) is entirely unsupported in 3GP and will be composited against black or dropped. The default audio bitrate of 64k in this tool reflects genuine 3GP usage conventions, but it is a significant step down from typical MOV audio quality. File sizes will generally be much smaller than the source MOV, primarily because the audio bitrate reduction and the mobile-tuned CRF work together to aggressively reduce data. One subtle issue to watch for: MOV files from Final Cut Pro or DaVinci Resolve may embed timecode tracks, color metadata (color primaries, transfer characteristics), or embedded LUTs; none of these are preserved in 3GP output.