Free online AVC to 3GPP converter

What the AVC format is

In video files, AVC means Advanced Video Coding, also called H.264 or MPEG-4 Part 10. A file with the .avc extension commonly contains a raw H.264 elementary stream rather than a complete multimedia container, so it may have video only, no audio track, and limited metadata.

Security cameras, digital cameras, mobile devices, broadcast encoders, and video-processing tools can create AVC streams. You can also encounter .avc files after extracting H.264 video from an MP4, transport stream, or proprietary recording format. The extension alone does not prove that the file is raw AVC; some applications use it for H.264 video with application-specific metadata.

What the 3GPP format is

3GPP is a mobile multimedia container usually identified by .3gp. It was designed for cellular phones and supports combinations of H.263, MPEG-4 Part 2, H.264/AVC, AMR audio, AAC audio, and related timing and metadata tracks.

A 3GPP file can be smaller and more compatible with older mobile hardware than a modern MP4, especially when it uses a low resolution, modest bitrate, H.263 or baseline H.264 video, and AMR-NB audio. Newer phones generally handle MP4 more reliably, so 3GPP is mainly useful when a specific handset, messaging system, embedded player, or legacy application requires .3gp.

How to convert AVC to 3GPP

Using 101convert.com

You can convert the file for free on 101convert.com without installing software. Select the Video converter, upload the .avc file, choose 3GPP or .3gp as the output format, start the conversion, and download the result. If the service offers device presets, select the target phone or choose a low-resolution mobile preset.

Using FFmpeg

FFmpeg is the most controllable desktop option. For a raw H.264 stream with no audio, run:

ffmpeg -f h264 -i input.avc -c:v libx264 -profile:v baseline -level 3.0 -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -an -f 3gp output.3gp

The -f h264 option tells FFmpeg how to interpret a raw AVC input. -profile:v baseline and -pix_fmt yuv420p improve compatibility with older phones; the filter makes both dimensions even, which many H.264 encoders require. Remove -f h264 if the source is actually a container that FFmpeg can identify, such as an MP4 file renamed to .avc.

To add AAC audio from a separate file, use:

ffmpeg -f h264 -i input.avc -i audio.wav -c:v libx264 -profile:v baseline -level 3.0 -pix_fmt yuv420p -c:a aac -b:a 64k -ar 44100 -shortest -f 3gp output.3gp

For a source that already contains audio, omit the raw-input option only when the source is a recognized container:

ffmpeg -i input.mp4 -c:v libx264 -profile:v baseline -level 3.0 -pix_fmt yuv420p -c:a aac -b:a 64k -movflags +faststart -f 3gp output.3gp

For very old phones that reject H.264 or AAC, encode the legacy combination of H.263 video and AMR-NB audio:

ffmpeg -i input.avc -c:v h263 -s 176x144 -r 15 -b:v 192k -c:a libopencore_amrnb -ar 8000 -ac 1 -b:a 12.2k -f 3gp output.3gp

That last command requires an FFmpeg build with AMR-NB encoding support. If the source has no audio, use -an instead of the audio options. A graphical FFmpeg front end can expose the same settings through Output format → 3GPP, but the exact menu names depend on the application.

Quality, compatibility, and limitations

Changing the container does not improve AVC quality. Re-encoding H.264 can reduce quality, so use stream copying only when the existing video and audio codecs are accepted by the target 3GPP device:

ffmpeg -i input.mp4 -c copy -f 3gp output.3gp

Stream copying will fail or produce an unusable file when the source has unsupported codecs, incompatible H.264 features, variable dimensions, or audio the target device cannot decode. Re-encoding with baseline H.264, even dimensions, a small frame size such as 176x144 or 320x240, and a bitrate suited to the phone is safer for legacy hardware.

A raw .avc stream may not contain a reliable frame rate, duration, rotation flag, or audio track. FFmpeg may therefore need an explicit frame rate, such as -r 25 or -r 30, and the converted file may require manual rotation or audio synchronization. Test the resulting .3gp on the actual device because 3GPP support varies substantially between phone models.