Convert MP3 to TOC

A .toc file is needed when CD-authoring software such as cdrdao requires a text-based disc layout instead of a single audio file. The practical task is to decode the MP3 tracks to CD-compatible WAV files and create a TOC that references them.

What the MP3 format is

MP3 is a lossy compressed audio format identified by the .mp3 extension. Music players, phones, streaming services, media libraries, and audio editors commonly use it because it stores playable audio in much less space than uncompressed PCM. MP3 compression removes information, so it is unsuitable as a quality-preserving source for later editing or disc mastering.

What the TOC format is

In audio disc-authoring software, .toc usually means a cdrdao table-of-contents file. It is a plain-text disc layout that specifies the disc type, track order, track boundaries, pauses, indexes, and referenced audio files. It does not contain the audio samples; the WAV or other source files named in it must remain available at the specified paths.

A TOC is useful when cdrdao needs precise control over an audio CD layout. It is not a general-purpose playback format, and creating one does not turn an MP3 into a self-contained audio file. For ordinary playback or sharing, retain the MP3. For a standard audio CD, use 44.1 kHz, 16-bit, stereo PCM WAV files and a TOC.

How to create a TOC from MP3 files

1. Install FFmpeg for audio decoding and cdrdao for TOC-based CD authoring. Use your operating system's package manager or the projects' official distribution channels.
2. Decode each MP3 to a CD-compatible WAV file. For example:
   ffmpeg -i "track01.mp3" -ar 44100 -ac 2 -c:a pcm_s16le "track01.wav"
3. Create a UTF-8 plain-text file named album.toc in the same directory as the WAV files. A basic two-track layout is:

CD_DA

TRACK AUDIO
FILE "track01.wav" 0

TRACK AUDIO
FILE "track02.wav" 0

4. Replace the filenames with the actual files and preserve the referenced paths. Add tracks in the required order. More advanced cdrdao syntax is needed for nonstandard pauses, indexes, pregaps, data tracks, or multisession discs.
5. Identify the recorder with cdrdao scanbus, then test or write the layout. A simulation uses a command such as cdrdao write --simulate --device /dev/sr0 album.toc; replace /dev/sr0 with the device identifier on your system. Remove --simulate only when the layout and track boundaries are correct.

Audacity can provide the desktop conversion step through File → Export Audio; choose WAV, 16-bit PCM, 44.1 kHz, and stereo, then create the TOC separately with cdrdao. Online services such as CloudConvert and Zamzar can also convert MP3 to WAV, but they generally do not generate a valid cdrdao TOC. Do not upload confidential recordings, and verify the downloaded WAV parameters before referencing them.

If the target application specifically accepts a CUE sheet, create a CUE file instead. CUE is more widely supported for simple audio-disc layouts, while TOC is primarily associated with cdrdao.

Quality and compatibility limitations

Decoding an MP3 to WAV does not restore information removed by MP3 compression. Use the highest-quality original available and avoid encoding the audio to another lossy format before conversion.

Check that every WAV is stereo, 44.1 kHz, 16-bit PCM. cdrdao or the recorder may reject other parameters, and automatic resampling can change timing. MP3 encoder delay and padding can also shift track starts and ends, so a TOC built from separate MP3 files may not reproduce the boundaries of the original CD exactly.