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This repository was archived by the owner on Dec 2, 2025. It is now read-only.
This repository was archived by the owner on Dec 2, 2025. It is now read-only.

Some Dolby Atmos (E-AC-3 JOC) files have wrong length #42

@doctRay

Description

@doctRay

The length of some Dolby Atmos files after download are way longer that it should be. (Also, bitrate data are wrong.)
It can be easily fixed and back to normal using FFmpeg to copy the stream into an .mp4 container.

Problem seems to be in the audio stream, since there is a correct "source duration":
Audio
ID : 1
Format : E-AC-3 JOC
Format/Infos : Enhanced AC-3 with Joint Object Coding
Format, Nom commercial IfAny : Dolby Digital Plus with Dolby Atmos
Identifiant du codec : ec-3
Durée : 22 min 34 s
Durée de la source : 3 min 8 s

The bad duration also appear in the MPEG-4 container with a wrong bitrate:
Format : MPEG-4
Format, Profil : Apple audio with iTunes info
Identifiant du codec : M4A (isom/iso5/hlsf/cmfc/ccea/M4A /mp42)
Taille du fichier : 17,8 Mio
Durée : 22 min 34 s
Type de débit global : Constant
Débit global : 111 kb/s
Titre : Billyeoon Goyangi (Do the Dance)

MediaInfo of remuxed .mp4 file with FFmpeg using command ffmpeg -i [input].m4a] -vn -c:a copy [output].mp4:
Format : MPEG-4
Format, Profil : Base Media
Identifiant du codec : isom (isom/dby1/iso2/mp41)
Taille du fichier : 17,3 Mio
Durée : 3 min 8 s
Type de débit global : Constant
Débit global : 769 kb/s
Titre : Billyeoon Goyangi (Do the Dance)
///
Audio
ID : 1
Format : E-AC-3 JOC
Format/Infos : Enhanced AC-3 with Joint Object Coding
Format, Nom commercial IfAny : Dolby Digital Plus with Dolby Atmos
Identifiant du codec : ec-3
Durée : 3 min 8 s
Durée de la source : 3 min 8 s
Type de débit : Constant
Débit : 768 kb/s

This bug seems to be random since some Atmos files have correct duration.
I don't know if this issue can be posted here since the downloader page doesn't have an issues page.

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