Convert HEVC to 3GP — Free Online Tool
Convert HEVC/H.265 video files to 3GP format optimized for 3G mobile devices, re-encoding through H.264 (libx264) with AAC audio for maximum compatibility on older handsets and low-bandwidth networks. Ideal for shrinking high-efficiency HDR or 4K HEVC content down to a mobile-friendly container that virtually every feature phone and early smartphone can play.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your HEVC file here
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Settings
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
HEVC and 3GP are fundamentally incompatible in terms of typical device support — most 3GP players expect H.264 video and AAC audio, not H.265. This conversion therefore fully re-encodes the video stream from HEVC (libx265) to H.264 (libx264) using CRF 23, which is a medium-quality constant-rate-factor setting that balances file size with visual fidelity. The audio is encoded to AAC at 64k bitrate, a low but functional quality suitable for voice and basic media on constrained mobile connections. A scaling filter (scale=trunc(iw/2)*2:trunc(ih/2)*2) ensures the output frame dimensions are always divisible by 2, which is a hard requirement for H.264 encoding and prevents errors when the source HEVC file has odd pixel dimensions. Because full re-encoding is required, this conversion is computationally intensive and will take longer than a simple remux.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. This command runs entirely in your browser via FFmpeg.wasm but is identical to what you would run in a terminal on your desktop for files over 1GB. |
-i input.hevc
|
Specifies the input file, which is an HEVC/H.265 elementary stream. FFmpeg will demux and decode the H.265 video for re-encoding into H.264 for the 3GP container. |
-c:v libx264
|
Sets the video encoder to libx264, transcoding the input HEVC stream into H.264 — the codec expected by 3GP players on mobile devices and the only widely supported video codec in the 3GP specification. |
-c:a aac
|
Encodes the audio stream to AAC, which is the standard audio codec for 3GP files and offers broad compatibility across feature phones, Symbian devices, and early Android handsets. |
-crf 23
|
Sets the Constant Rate Factor for the H.264 encoder to 23, a medium-quality setting that balances visual fidelity and file size. Lower values increase quality and file size; higher values (up to 51) reduce both, which may be desirable for the bandwidth-constrained environments 3GP targets. |
-b:a 64k
|
Sets the AAC audio bitrate to 64 kilobits per second, a low but serviceable quality appropriate for voice and basic media playback over 3G connections and on small mobile speakers. |
-vf scale=trunc(iw/2)*2:trunc(ih/2)*2
|
Applies a video filter that rounds the width and height of the output down to the nearest even integer. H.264 with YUV 4:2:0 encoding requires dimensions divisible by 2, and HEVC sources occasionally have odd pixel dimensions that would otherwise cause the encode to fail. |
output.3gp
|
Specifies the output filename with the .3gp extension, instructing FFmpeg to wrap the H.264 video and AAC audio into the 3GP multimedia container format defined by the Third Generation Partnership Project. |
Common Use Cases
- Downscaling HEVC-recorded dashcam or security camera footage to send via MMS or messaging apps on older 3G-only mobile phones
- Distributing short video clips to feature phone users in regions where 3G networks and low-end handsets remain common
- Converting HEVC content from a modern drone or action camera into a 3GP format compatible with legacy in-car entertainment systems or portable media players that predate H.265 support
- Preparing HEVC video archives for playback on early Android or Symbian smartphones where 3GP is the native supported format
- Reducing the file size of HEVC home videos to share via Bluetooth or low-bandwidth file transfer protocols that cap at small file sizes
- Creating mobile-compatible preview clips from HEVC master files for field review on older company-issued handsets without H.265 decoding capability
Frequently Asked Questions
The 3GP specification was designed around codecs available in the early 2000s to mid-2010s, primarily H.264 and AAC. Embedding an H.265/HEVC stream inside a 3GP container is not a standardized combination, and virtually no 3GP-compatible device or player will recognize or decode it. Full re-encoding from libx265 to libx264 is therefore necessary to produce a file that actually plays in 3GP environments.
HEVC achieves roughly twice the compression efficiency of H.264 at equivalent quality, so re-encoding to H.264 at CRF 23 will typically produce a 3GP file that is noticeably larger than the source HEVC — often 1.5x to 2.5x bigger for the same visual quality. If you increase the CRF value (e.g., to 30 or 35) in the command, you can reduce the output file size at the cost of more visible compression artifacts, which may be acceptable given 3GP's intended use on small mobile screens.
No. HDR metadata (such as HDR10 or Dolby Vision color information) encoded in the HEVC source will be lost during re-encoding to H.264 for the 3GP container. The H.264 codec used here does not support HDR10 signaling, and 3GP devices lack HDR display capability entirely. The output will be tone-mapped or clipped to standard dynamic range, which may cause highlight detail loss or washed-out colors if the source is a high-dynamic-range HEVC file.
The -vf scale=trunc(iw/2)*2:trunc(ih/2)*2 filter ensures the output video width and height are each divisible by 2, which is a strict requirement of the H.264 codec's YUV 4:2:0 chroma subsampling. HEVC sources sometimes have odd pixel dimensions that H.264 cannot encode directly. Removing this filter could cause FFmpeg to throw an error if your source happens to have an odd-numbered width or height, so it is safest to leave it in place.
To reduce file size, raise the CRF value — for example, change -crf 23 to -crf 30 or -crf 35. Higher CRF means lower quality but smaller files, which is often acceptable for the small screens and limited storage of 3GP target devices. For audio, lower the bitrate by changing -b:a 64k to -b:a 32k or -b:a 48k. Keep in mind that at 32k AAC audio begins to sound noticeably degraded, particularly for music, though it remains intelligible for voice content.
Yes. On Linux or macOS, you can use a shell loop: for f in *.hevc; 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%.hevc}.3gp"; done. On Windows Command Prompt, use: for %f in (*.hevc) 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". Each file will be fully re-encoded, so batch processing large HEVC files will be time-consuming.
Technical Notes
The 3GP format imposes strict constraints that make HEVC-to-3GP one of the more involved conversions: it requires a full decode-and-reencode pipeline rather than a stream copy, because no widely deployed 3GP implementation supports H.265. The output H.264 stream is encoded with libx264 at CRF 23, which produces good quality for standard-definition and lower-resolution content but will result in noticeably larger files than the HEVC source at equivalent visual quality — a direct consequence of H.264's lower compression efficiency. Chapters, subtitles, and multiple audio tracks present in the HEVC source are all silently dropped, as 3GP supports none of these features. Metadata such as title or creation date tags is also generally lost. For 4K or 8K HEVC sources, consider downscaling the resolution explicitly (e.g., adding scale=640:360 to the filter chain) before conversion, since 3GP was designed for sub-VGA and QVGA resolutions and high-resolution output will be unnecessarily large and potentially unplayable on actual 3G devices. The AAC audio codec at 64k is the most universally compatible audio choice for 3GP playback across Symbian, early Android, and feature phone platforms.