sndinfo

Sound file information utility

The sndinfo utility displays detailed information about audio files including format, sample rate, bit depth, duration, and optional instrument/broadcast metadata.

Syntax

sndinfo [options] soundfile [soundfile ...]

Arguments

• soundfile - One or more sound files to examine

Options

Option	Description
-i	Display instrument information (sample loops, base note, velocity)
-i<N>	Display instrument information with detail level N
-b	Display broadcast wave (BWF) information
-b<N>	Display broadcast information with detail level N
-j <N>	(Ignored, for compatibility)

Examples

Display basic file information

sndinfo myfile.wav

Output:

myfile.wav:
    srate 44100, stereo, 16 bit WAV, 3.456 seconds
    (152438 sample frames)

Examine multiple files

sndinfo *.wav

Show instrument information

sndinfo -i sample.wav

Output includes:

myfile.wav:
    srate 44100, mono, 24 bit WAV, 2.500 seconds
    (110250 sample frames)
  Gain        : 0
  Base note   : 60
  Velocity    : 64 - 127
  Key         : 0 - 127
  Loop points : 1
  0     Mode : fwrd    Start :   1000   End :  50000   Count :      0

Show broadcast wave information

sndinfo -b broadcast.wav

Output includes:

broadcast.wav:
    srate 48000, stereo, 24 bit WAV, 60.000 seconds
    (2880000 sample frames)
Description      : News segment recorded 2024-01-15
Originator       : Studio A
Origination ref  : REF123456
Origination date : 2024-01-15
Origination time : 14:30:00
BWF version      : 1

Information displayed

Basic information (always shown)

• Sample rate: Samples per second (e.g., 44100, 48000)
• Channel configuration: Mono, stereo, quad, hex, oct, or N-channel
• Bit depth: 8, 16, 24, or 32 bits per sample
• File format: WAV, AIFF, FLAC, etc.
• Duration: Length in seconds
• Sample frames: Total number of sample frames

Instrument information (-i flag)

For sampler-compatible files:

• Gain: Overall gain adjustment
• Base note: MIDI note number (middle C = 60)
• Velocity range: Minimum to maximum velocity values
• Key range: MIDI key range for sample mapping
• Loop points: Number of defined loops
• Loop details: For each loop:
  • Mode: none, forward, backward, or alternating
  • Start point: Sample frame number
  • End point: Sample frame number
  • Count: Number of times to repeat

Broadcast wave information (-b flag)

For BWF (Broadcast Wave Format) files:

• Description: Content description
• Originator: Creator/recording engineer
• Origination reference: Unique identifier
• Origination date: Recording date (YYYY-MM-DD)
• Origination time: Recording time (HH:MM:SS)
• BWF version: Broadcast Wave Format version
• UMID: Unique Material Identifier
• Coding history: Processing history

Supported file formats

sndinfo supports all formats readable by libsndfile:

Common formats

• WAV: Microsoft Wave (PCM, float, compressed)
• AIFF/AIFC: Apple Audio Interchange File Format
• FLAC: Free Lossless Audio Codec
• OGG: Ogg Vorbis (if libsndfile built with support)

Professional formats

• CAF: Apple Core Audio Format
• RF64: 64-bit extended WAV
• W64: Sony Wave64
• BWF: Broadcast Wave Format

Legacy formats

• AU/SND: Sun/NeXT audio
• IRCAM: IRCAM soundfile
• VOC: Creative Voice
• PAF: Paris Audio File
• SVX: Amiga IFF/SVX

Channel configurations

Channels	Description
1	Monaural
2	Stereo
4	Quad (quadraphonic)
6	Hex (5.1 surround)
8	Oct (7.1 surround)
N	N-channel

Sample formats

Format	Description
8-bit	Unsigned or signed char
16-bit	Signed short integer (CD quality)
24-bit	Signed 24-bit integer (high quality)
32-bit	Signed long integer or float
64-bit	Double precision float

Usage patterns

Check file before processing

sndinfo input.wav
# Verify format, then process
scale -F 0.5 input.wav output.wav

Batch file examination

for file in *.wav; do
  echo "Examining $file"
  sndinfo "$file"
  echo "---"
done

Verify sample rate

sndinfo *.wav | grep srate

Find files with loops

sndinfo -i *.wav | grep "Loop points"

Error handling

File not found

myfile.wav:
    could not find

Check:

• File path is correct
• File exists in current directory or SFDIR path
• File permissions allow reading

Not a sound file

myfile.dat: Not a sound file

The file is not a recognized audio format.

Environment variables

• SFDIR: Semicolon-separated list of directories to search for sound files
• SSDIR: Additional search directory for sound files

Related utilities

• scale - Scale audio files
• mixer - Mix audio files
• srconv - Convert sample rates