Which audio format should I use?

It depends on your use case. For maximum compatibility: MP3 at 192kbps. For modern applications: AAC at 192kbps (slightly better than MP3, smaller file). For archival: FLAC (lossless, ~50% of WAV size). For web/VoIP/streaming: Opus at 128kbps (best quality at low bitrates). For video production: AAC at 256kbps (industry standard). Avoid WAV for distribution (huge files); use it only for editing.

Is FLAC better than MP3?

FLAC is lossless (preserves exact original audio), while MP3 is lossy (discards audio data). FLAC is "better" in terms of quality but produces 3-5x larger files than MP3 at 192kbps. For archival or audiophile use, FLAC is preferred. For casual listening, mobile devices, or streaming, MP3 at 192-320kbps is sufficient and indistinguishable from lossless for most listeners.

What is the best audio format for streaming?

For modern streaming: Opus at 96-128kbps (best quality at low bitrates, supported by Chrome/Firefox/Android). For broad compatibility including iOS: AAC at 128-192kbps. For legacy systems: MP3 at 192kbps. Spotify uses Ogg Vorbis/Opus, Apple Music uses AAC, YouTube uses Opus/AAC. The trend is moving toward Opus for new platforms.

Can I convert lossy audio to lossless?

You can convert files (e.g., MP3 to FLAC), but you cannot restore lost audio data. Once audio is compressed with a lossy codec (MP3, AAC, Opus), the discarded data is gone forever. Converting MP3 to FLAC just produces a larger file with the same quality as the MP3. Always archive from the original lossless source if possible.

What bitrate is CD quality?

CD audio is uncompressed PCM at 1411kbps (16-bit, 44.1kHz, stereo). Lossy codecs (MP3, AAC, Opus) at 192-320kbps are generally indistinguishable from CD quality for most listeners in blind tests. FLAC at default settings preserves exact CD quality at ~50-60% of WAV size. The CD-quality threshold for lossy codecs is called "transparency," typically around 192kbps for MP3 and 128kbps for AAC/Opus.

Audio Format Conversion Guide: MP3, AAC, FLAC, OGG, Opus Compared

Choosing the right audio format can be confusing. MP3, AAC, FLAC, OGG, Opus, WAV, AIFF — there are too many options. This guide compares the major audio formats, explains when to use each, and provides FFmpeg commands for all common conversions.

Audio format categories

Audio formats fall into three categories:

1. Uncompressed (raw PCM)

WAV, AIFF
Maximum quality, huge files
Used in audio editing and production

2. Lossless compressed

FLAC, ALAC, APE
Exact original quality, smaller than uncompressed
Used for archival and audiophile listening

3. Lossy compressed

MP3, AAC, OGG Vorbis, Opus, WMA
Discards inaudible audio data for small files
Used for distribution, streaming, mobile devices

Format comparison table

Format	Type	Quality	File size	Compatibility	Use case
WAV	Uncompressed	Lossless	Huge	Universal	Audio editing
FLAC	Lossless	Lossless	Medium	Good	Archival
ALAC	Lossless	Lossless	Medium	Apple ecosystem	Apple archival
MP3	Lossy	Good	Small	Universal	Distribution
AAC	Lossy	Better	Small	Excellent	Modern distribution
OGG Vorbis	Lossy	Good	Small	Good (no iOS)	Open source
Opus	Lossy	Best	Smallest	Modern browsers	Streaming, VoIP
WMA	Lossy	Good	Small	Windows only	Legacy

When to use each format

WAV (uncompressed)

Use when: Editing audio, maximum quality needed
Avoid when: Distributing files (too large)
Bitrate: 1411kbps (CD quality, 16-bit/44.1kHz/stereo)

FLAC (lossless)

Use when: Archival, audiophile listening
Avoid when: Mobile devices with limited storage
Bitrate: ~800kbps (varies with content)
File size: ~50-60% of WAV

MP3 (lossy)

Use when: Maximum compatibility needed
Avoid when: You need best quality at low bitrate
Recommended bitrate: 192kbps (good), 320kbps (maximum)
Compatibility: Every device, every software

AAC (lossy)

Use when: Modern applications, video production
Avoid when: Old devices that only support MP3
Recommended bitrate: 128-192kbps
Compatibility: All modern devices, browsers

Opus (lossy)

Use when: Web streaming, VoIP, low-latency applications
Avoid when: Need iOS Safari compatibility (limited support)
Recommended bitrate: 96-128kbps (transparent at 128kbps)
Compatibility: Chrome, Firefox, Android (limited Safari/iOS)

FFmpeg conversion commands

Convert to MP3

bash

# High quality MP3
ffmpeg -i input.wav -c:a libmp3lame -b:a 320k output.mp3

# Standard quality MP3
ffmpeg -i input.wav -c:a libmp3lame -b:a 192k output.mp3

# Voice MP3
ffmpeg -i input.wav -c:a libmp3lame -b:a 96k -ac 1 output.mp3

Convert to AAC

bash

# AAC in M4A container
ffmpeg -i input.wav -c:a aac -b:a 192k output.m4a

# AAC in ADTS container
ffmpeg -i input.wav -c:a aac -b:a 192k output.aac

# High quality AAC
ffmpeg -i input.wav -c:a aac -b:a 256k output.m4a

Convert to FLAC

bash

# Lossless FLAC
ffmpeg -i input.wav -c:a flac output.flac

# FLAC with compression level (0-12, default 5)
ffmpeg -i input.wav -c:a flac -compression_level 8 output.flac

Convert to Opus

bash

# Opus in OGG container
ffmpeg -i input.wav -c:a libopus -b:a 128k output.opus

# Opus for voice
ffmpeg -i input.wav -c:a libopus -b:a 64k -application voip output.opus

Convert to OGG Vorbis

bash

ffmpeg -i input.wav -c:a libvorbis -b:a 192k output.ogg

Convert to WAV

bash

# Standard WAV (CD quality)
ffmpeg -i input.mp3 -ar 44100 -ac 2 -c:a pcm_s16le output.wav

# 24-bit WAV
ffmpeg -i input.flac -c:a pcm_s24le output.wav

Common conversion scenarios

Extract audio from video

bash

ffmpeg -i input.mp4 -vn -c:a libmp3lame -b:a 192k output.mp3

See our MP4 to MP3 Tutorial for details.

Convert FLAC to MP3

bash

ffmpeg -i input.flac -c:a libmp3lame -b:a 320k output.mp3

Convert M4A to MP3

bash

ffmpeg -i input.m4a -c:a libmp3lame -b:a 192k output.mp3

Convert WAV to FLAC

bash

ffmpeg -i input.wav -c:a flac -compression_level 8 output.flac

Batch conversion

bash

# Convert all WAV files in current directory to MP3
for f in *.wav; do
  ffmpeg -i "$f" -c:a libmp3lame -b:a 192k "${f%.wav}.mp3"
done

Bitrate guide

Bitrate	Quality	Use case	File size per minute
64k	Voice only	Voice memo, podcast	~0.5 MB
96k	Acceptable	Voice, low-quality music	~0.7 MB
128k	Good	Casual music, streaming	~1 MB
192k	Very good	Recommended for music	~1.5 MB
256k	High	High quality music	~2 MB
320k	Maximum	Archival, audiophile	~2.5 MB
Lossless	Perfect	Archival, editing	~10 MB (FLAC)

Quality comparison

At the same bitrate, perceived quality ranking:

Opus > AAC > Ogg Vorbis > MP3

Approximate transparency thresholds (where listeners can't distinguish from CD):

Opus: 128kbps
AAC: 160kbps
Ogg Vorbis: 192kbps
MP3: 256kbps

Sample rate and channels

Sample rate

Rate	Use case
8000 Hz	Telephone quality
22050 Hz	Half CD quality
44100 Hz	CD quality (standard)
48000 Hz	Professional video (recommended)
96000 Hz	High-resolution audio
192000 Hz	Studio recording

Channels

-ac 1: Mono (single channel)
-ac 2: Stereo (two channels, default for music)
-ac 6: 5.1 surround sound

bash

# Convert stereo to mono
ffmpeg -i input.mp3 -ac 1 -c:a libmp3lame -b:a 96k output.mp3

# Convert mono to stereo
ffmpeg -i input.mp3 -ac 2 -c:a libmp3lame -b:a 192k output.mp3

Common issues

Issue	Cause	Solution
"Unknown encoder"	Encoder not compiled in	Use built-in `aac` instead of `libmp3lame`
File too large	Lossless codec or high bitrate	Use MP3/AAC at 192kbps
Poor quality	Bitrate too low	Use 192kbps minimum for music
Audio sync issues	Sample rate mismatch	Use `-ar 44100` or `-ar 48000`
Can't play Opus	Old player	Use AAC or MP3 instead
Conversion fails	DRM protected source	Remove DRM first (if legal)

Summary

Audio format selection summary:

Maximum compatibility: MP3 at 192kbps
Modern standard: AAC at 192kbps
Best quality at low bitrate: Opus at 128kbps
Archival: FLAC
Audio editing: WAV

For format conversion, FFmpeg is the universal tool. The basic pattern is ffmpeg -i input.ext -c:a [codec] -b:a [bitrate] output.ext.

Quick reference:

Universal MP3: ffmpeg -i input.wav -c:a libmp3lame -b:a 192k output.mp3
Modern AAC: ffmpeg -i input.wav -c:a aac -b:a 192k output.m4a
Lossless FLAC: ffmpeg -i input.wav -c:a flac output.flac
Best Opus: ffmpeg -i input.wav -c:a libopus -b:a 128k output.opus

For FFmpeg basics, see our FFmpeg Getting Started Tutorial.

Audio Format Conversion Guide: MP3, AAC, FLAC, OGG, Opus Compared ​

Audio format categories ​

1. Uncompressed (raw PCM) ​

2. Lossless compressed ​

3. Lossy compressed ​

Format comparison table ​

When to use each format ​

WAV (uncompressed) ​

FLAC (lossless) ​

MP3 (lossy) ​

AAC (lossy) ​

Opus (lossy) ​

FFmpeg conversion commands ​

Convert to MP3 ​

Convert to AAC ​

Convert to FLAC ​

Convert to Opus ​

Convert to OGG Vorbis ​

Convert to WAV ​

Common conversion scenarios ​

Extract audio from video ​

Convert FLAC to MP3 ​

Convert M4A to MP3 ​

Convert WAV to FLAC ​

Batch conversion ​

Bitrate guide ​

Quality comparison ​

Sample rate and channels ​

Sample rate ​

Channels ​

Common issues ​

Summary ​

References ​

Audio Format Conversion Guide: MP3, AAC, FLAC, OGG, Opus Compared

Audio format categories

1. Uncompressed (raw PCM)

2. Lossless compressed

3. Lossy compressed

Format comparison table

When to use each format

WAV (uncompressed)

FLAC (lossless)

MP3 (lossy)

AAC (lossy)

Opus (lossy)

FFmpeg conversion commands

Convert to MP3

Convert to AAC

Convert to FLAC

Convert to Opus

Convert to OGG Vorbis

Convert to WAV

Common conversion scenarios

Extract audio from video

Convert FLAC to MP3

Convert M4A to MP3

Convert WAV to FLAC

Batch conversion

Bitrate guide

Quality comparison

Sample rate and channels

Sample rate

Channels

Common issues

Summary

References