Comparison of iOS call recording tools

About

This post compares the quality of different call recording tools available on the latest iOS.

Option 1: Voicemail recording (control)

Option 2:New iOS 18 built-in call recording functionality

Option 3: Third-party recording applications, Rev Call Recorder in particular.

Skim to the bottom for the mediainfo outputs.

Voicemail audio

• File type: M4A
• Audio format: AAC, Low-Complexity profile (AAC-LC)
• Sample Rate: 44100 Hz (44.1 kHz)
• Audio channels: 2 (L R)
• Bit Depth: 16
• Nomimal bitrate: 128 kb/s

Does contain iTunSMPB ID3 tags for gapless playback

iOS 18 call recording audio

• File type: M4A
• Audio format: AAC, Low-Complexity profile (AAC-LC)
• Sample rate: 44100 Hz (44.1 kHz)
• Audio channels: 2 (L R)
• Nominal bitrate: 256 kb/s

Does contain iTunSMPB ID3 tags for gapless playback

Third-party call recording application

• File type: MP3
• Audio format: MPEG - Version 2
• Bit rate: 32 kb/s
• Single channel

Does NOT contain iTunSMPB ID3 tag for gapless playback

Mediainfo outputs

Third-party call recording application

General
Complete name                            : 11_18_2024__8_45_AM.mp3
Format                                   : MPEG Audio
File size                                : 1.71 MiB
Duration                                 : 7 min 28 s
Overall bit rate mode                    : Constant
Overall bit rate                         : 32.0 kb/s

Audio
Format                                   : MPEG Audio
Format version                           : Version 2
Format profile                           : Layer 3
Duration                                 : 7 min 28 s
Bit rate mode                            : Constant
Bit rate                                 : 32.0 kb/s
Channel(s)                               : 1 channel
Sampling rate                            : 22.05 kHz
Frame rate                               : 38.281 FPS (576 SPF)
Compression mode                         : Lossy
Stream size                              : 1.71 MiB (100%)

iOS 18 call recording audio

General
Complete name                            : Call with Voya 401k.m4a
Format                                   : MPEG-4
Format profile                           : Apple audio with iTunes info
Codec ID                                 : M4A  (M4A /isom/mp42)
File size                                : 19.6 MiB
Duration                                 : 13 min 30 s
Overall bit rate mode                    : Constant
Overall bit rate                         : 203 kb/s
Encoded date                             : 2024-11-20 15:57:17 UTC
Tagged date                              : 2024-11-20 15:57:31 UTC

Audio
ID                                       : 1
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 13 min 30 s
Source duration                          : 13 min 30 s
Bit rate mode                            : Constant
Bit rate                                 : 202 kb/s
Nominal bit rate                         : 256 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 44.1 kHz
Frame rate                               : 43.066 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 19.5 MiB (99%)
Source stream size                       : 19.5 MiB (99%)
Title                                    : Core Media Audio
Encoded date                             : 2024-11-20 15:57:17 UTC
Tagged date                              : 2024-11-20 15:57:31 UTC

Voicemail

General
Complete name                            : voicemail-12903112736.m4a
Format                                   : MPEG-4
Format profile                           : Apple audio with iTunes info
Codec ID                                 : M4A  (M4A /isom/mp42)
File size                                : 448 KiB
Duration                                 : 37 s 760 ms
Overall bit rate mode                    : Constant
Overall bit rate                         : 97.1 kb/s
Encoded date                             : 2024-11-18 04:45:11 UTC
Tagged date                              : 2024-11-18 04:45:11 UTC

Audio
ID                                       : 1
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 37 s 760 ms
Source duration                          : 37 s 825 ms
Bit rate mode                            : Constant
Bit rate                                 : 96.0 kb/s
Nominal bit rate                         : 128 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 44.1 kHz
Frame rate                               : 43.066 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 440 KiB (98%)
Source stream size                       : 440 KiB (98%)
Title                                    : Core Media Audio
Encoded date                             : 2024-11-18 04:45:11 UTC
Tagged date                              : 2024-11-18 04:45:11 UTC