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Estimating audio file size

Estimating the size of an audio file can be essential for various use cases, from managing storage space to understanding file transfer times.

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Estimate audio file size by its duration, format, and other properties.
Total: 5.04 MB

Factors affecting audio file size

  • Audio format: Different formats use different compression methods.
  • Duration: The length of the audio file (in seconds or minutes).
  • Bitrate: The amount of data processed per second in audio.
  • Sample rate: Number of samples per second (e.g., 44.1 kHz).
  • Bit depth: The number of bits used to represent each sample (e.g., 16-bit, 24-bit).
  • Number of channels: Mono, stereo, or multi-channel audio.
  • Compression: For compressed formats.

Formulas for estimating

MP3 (compressed)

MP3 is a widely used lossy compression format, where file size is determined by the bitrate and duration. The formula is:

File Size (bytes) = (Bitrate (kbps) × Duration (seconds)) ÷ 8

- Bitrate (kbps): The bitrate in kilobits per second (e.g., 128 kbps, 192 kbps).
- Duration (seconds): The length of the audio file in seconds.

WAV (uncompressed)

WAV files are uncompressed audio files. The file size can be estimated using the following formula:

File Size (bytes) = (Duration (seconds) × Sample Rate × Bit Depth × Number of Channels) ÷ 8

- Sample Rate (Hz): The number of samples per second (e.g., 44,100 Hz).
- Bit Depth: The bit depth per sample (e.g., 16-bit, 24-bit).
- Number of Channels: The number of audio channels (e.g., 1 for mono, 2 for stereo).

OGG (compressed)

OGG is another lossy compression format, similar to MP3 but typically providing better sound quality. The file size can be calculated using the same formula as MP3:

File Size (bytes) = (Bitrate (kbps) × Duration (seconds)) ÷ 8

MP4 (video with audio)

MP4 is a container format, typically used for both video and audio. To estimate the size of the audio stream (ignoring the video), use the same formula used for compressed formats:

File Size (bytes) = (Bitrate (kbps) × Duration (seconds)) ÷ 8

FLAC (lossless compression)

FLAC is a lossless compression format, which means it retains the original audio quality but reduces the file size. The file size can be estimated using:

File Size (bytes) = Uncompressed File Size × Compression Ratio

The Uncompressed File Size can be calculated using the WAV formula, and the Compression Ratio typically ranges from 30% to 60% of the original file size. But the final size may depend on the content and length of the audio. For small files, the impact of compression may be negligible.

AAC (compressed)

AAC is a lossy compression format that is similar to MP3 but offers better quality at the same bitrate. The file size is estimated using the same formula as MP3:

File Size (bytes) = (Bitrate (kbps) × Duration (seconds)) ÷ 8

AIFF (uncompressed)

AIFF (Audio Interchange File Format) is similar to WAV, and is typically an uncompressed format. To estimate the file size, you can use the same formula as WAV:

File Size (bytes) = (Duration (seconds) × Sample Rate × Bit Depth × Number of Channels) ÷ 8

How to estimate audio file size

Estimating the size of an audio file can be a simple process if you understand the properties that influence file size, such as duration, bitrate, sample rate, and format. By using the formulas provided in this article, you can easily calculate the expected size of audio files in various popular formats, whether they are compressed or uncompressed.