Free online 3PG to FLAC converter

Devices and older mobile-phone software may produce audio inside a 3PG/3GP container, while music editors and archival workflows commonly require FLAC. Converting it extracts the audio stream into a lossless FLAC file; any video stream is discarded.

What the 3PG format is

3PG is not a widely standardized audio extension. It commonly refers to a 3GPP media file with the usual .3gp extension renamed or mistyped as .3pg. Mobile phones, 3G video recorders, messaging applications, and older handset software created these files.

A 3GPP container can hold AMR, AAC, or other compressed audio, sometimes alongside video. Check the actual streams before conversion with ffprobe input.3pg. If the file is really a 3GPP file whose extension is wrong, renaming it to input.3gp can improve compatibility with applications that rely on the filename extension.

What the FLAC format is

FLAC is a lossless audio codec and container. It reduces file size compared with uncompressed PCM while preserving every sample, supports metadata such as artist and album fields, and is accepted by many music players, editors, servers, and archival tools.

FLAC is useful when you need editable or archive-friendly audio, but it does not restore quality removed by an AMR or AAC source. The resulting FLAC may be larger than the original 3PG file because it preserves the source samples without adding another lossy compression stage.

How to actually convert 3PG to FLAC

FFmpeg is the most dependable desktop option because it can read common 3GPP containers and AMR/AAC streams.

1. Install FFmpeg from a trusted package source for your operating system.
2. Inspect the file with ffprobe input.3pg. Confirm that an audio stream exists and note its codec and sample rate.
3. Convert the first audio stream with:
   ffmpeg -i input.3pg -map 0:a:0 -vn -c:a flac output.flac
4. Open output.flac in the target player or editor and verify its duration, channels, and metadata.

The -map 0:a:0 option selects the first audio stream, while -vn prevents video from being copied. To convert every file in a folder, run the command separately for each input so that filenames and stream selection remain clear.

If FFmpeg reports an invalid format, first try changing the filename from input.3pg to input.3gp without altering the file contents, then repeat the command. You can also convert the file for free on the 101convert.com website without installing software.

Quality, compatibility, and limitations

FLAC conversion is lossless only from the decoder onward: it preserves what the 3PG audio contains but cannot recover detail already discarded by AMR, AAC, or another lossy codec. Do not expect a higher-quality result than the source.

Some 3GPP files contain only video, unsupported codecs, damaged headers, or multiple audio streams. A file without an audio stream cannot produce a meaningful FLAC; for multiple streams, replace -map 0:a:0 with the appropriate stream selector after inspecting ffprobe output.