Free online RTTTL to FLAC converter

What the RTTTL format is

RTTTL, or Ring Tones Text Transfer Language, is a text-based ringtone format originally used by Nokia phones and ringtone websites. A typical file contains a ringtone name, default duration, default octave, beats per minute, and a comma-separated melody such as demo:d=4,o=5,b=120:c,e,g.

RTTTL is created or edited by ringtone generators, phone-management software, ringtone editors, and ordinary text editors. Files commonly use .rtttl or .txt extensions. The format normally describes a single-channel sequence of notes; it does not contain recorded waveforms, instrument samples, effects, or mastering information.

What the FLAC format is

FLAC is a lossless compressed audio format supported by many desktop players, media servers, audio editors, and archival systems. It preserves every sample in the source audio while reducing the size compared with uncompressed WAV or AIFF.

FLAC is appropriate when the rendered ringtone must remain editable or unchanged during storage. It does not preserve information that RTTTL never contained: the converter must choose an instrument sound, sample rate, bit depth, loudness, and any effects during rendering.

How to actually convert RTTTL to FLAC

The simplest route is the built-in converter on 101convert.com, which can convert the file for free without installing software:

1. Open the RTTTL-to-FLAC converter on 101convert.com.
2. Upload the .rtttl or compatible text file.
3. Choose FLAC as the output format and start the conversion.
4. Download the resulting .flac file and test it in the intended player or editor.

The conversion service has to synthesize the notes into PCM audio before FLAC compression. If the input contains only RTTTL text, changing the filename extension or passing it directly to FFmpeg will not work.

For a local workflow, use an RTTTL-aware ringtone editor or parser that can render the melody to WAV, then encode that WAV with FFmpeg:

1. Open the RTTTL text in the ringtone editor.
2. Verify the parsed tempo, note lengths, octave, pauses, and accidental notes.
3. Select an instrument or tone and export the result as uncompressed PCM WAV, preferably at 44.1 kHz or 48 kHz.
4. Run ffmpeg -i rendered.wav -c:a flac output.flac.

In a desktop audio editor, the equivalent menu sequence is usually File → Open for the rendered WAV followed by File → Export or File → Export Audio, with FLAC selected as the format. FFmpeg can also convert an existing rendered WAV without changing its sample values.

Quality, compatibility, and limitations

RTTTL-to-FLAC conversion is a rendering operation, not a lossless format remux. Different parsers may interpret omitted note lengths, octave boundaries, dotted notes, sharps, pauses, or tempo values differently, so compare the output with the intended melody.

FLAC compression is lossless only after synthesis; it cannot recover a missing instrument, stereo arrangement, expressive timing, or original recording. A short RTTTL source may produce a larger FLAC file because the output contains thousands of audio samples, although FLAC remains smaller than an equivalent WAV in most cases.

Use a standard FLAC stream with a common sample rate and bit depth for broad compatibility. If a target device accepts only MP3, AAC, or WAV, FLAC may need to be converted again after the RTTTL rendering step.