Is M4A truly AAC?

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Djard
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Joined: Fri Nov 05, 2010 6:25 pm
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Is M4A truly AAC?

Post by Djard » Wed Jan 17, 2018 12:53 am

When exporting a file as "M4A (AAC)," and using it in projects with AVIdemux, MKVToolNix, ConvertXtoDVD, Corel Video Studio and others, I experience a variety of problems, like audio delay or audio loss in an appended file when concatenating video files (I even renamed the file's extension from M4A to AAC). But when I recode the same exported file as an AAC in XMediaRecode, I experience no such issues.

Does FFmpeg AAC support render true AAC?
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steve
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Joined: Sat Dec 01, 2007 11:43 am
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Re: Is M4A truly AAC?

Post by steve » Wed Jan 17, 2018 10:43 am

Here are the details of an M4A (stereo) test file that I made just now:

Code: Select all

General
Complete name                            : ..../Desktop/untitled.m4a
Format                                   : MPEG-4
Format profile                           : Apple audio with iTunes info
Codec ID                                 : M4A  (isom/iso2)
File size                                : 239 KiB
Duration                                 : 9s 985ms
Overall bit rate mode                    : Constant
Overall bit rate                         : 196 Kbps
Encoded date                             : UTC 1904-01-01 00:00:00
Tagged date                              : UTC 1904-01-01 00:00:00
Writing application                      : Lavf56.40.101

Audio
ID                                       : 1
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 9s 985ms
Bit rate mode                            : Constant
Bit rate                                 : 192 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 44.1 KHz
Frame rate                               : 43.066 fps (1024 spf)
Compression mode                         : Lossy
Stream size                              : 239 KiB (100%)
Default                                  : Yes
Alternate group                          : 1
Encoded date                             : UTC 1904-01-01 00:00:00
Tagged date                              : UTC 1904-01-01 00:00:00
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