IRCAM to AAC Converter

IRCAM sound files originate from the Institut de Recherche et Coordination Acoustique/Musique — one of the world's foremost computer music laboratories, founded by composer Pierre Boulez in Paris. The format was created in the early 1980s to serve the research needs of IRCAM and has since been adopted by academic and artistic communities working at the intersection of science and sound. An IRCAM file begins with a 1024-byte header containing a magic number, sample rate, channel count, and an encoding type field that supports linear PCM (16/32-bit integer and 32-bit float), mu-law, and A-law variants. The header block also accommodates free-form annotation text, allowing researchers to embed experiment metadata directly in the audio file. Because the payload is uncompressed by default, recordings maintain full fidelity through successive analysis and resynthesis cycles — essential in psychoacoustic experimentation. Software such as Csound, libsndfile, and SoX reads and writes the format natively. Key advantages include a well-defined header that eliminates parsing ambiguity, support for floating-point samples essential in scientific DSP work, and deep roots in the computer music community ensuring continued tooling.

AAC (Advanced Audio Coding) is the successor to MP3, standardized by ISO/IEC as part of the MPEG-2 and later MPEG-4 specifications. Designed collaboratively by Fraunhofer, Dolby, Sony, Nokia, and AT&T, AAC delivers superior sound quality at equivalent or lower bit rates — a 96 kbps AAC stream generally matches a 128 kbps MP3 file in perceptual quality. The codec leverages a modified discrete cosine transform combined with advanced psychoacoustic modeling and temporal noise shaping. AAC serves as the default audio format for Apple's ecosystem (iTunes, iPhone, iPad), YouTube, and many streaming services. Its first advantage is excellent compression efficiency — high-fidelity audio using significantly less storage and bandwidth. Second, the format supports sample rates from 8 kHz to 96 kHz and up to 48 channels, suiting everything from voice calls to surround sound. Third, broad industry adoption by Apple and others ensures that virtually every modern device, browser, and media player handles AAC content natively without additional plugins.