1877351 - firefox not obeying audio delay in mulitple formats of video

Status: RESOLVED DUPLICATE of bug 1842375

(Core :: Audio/Video: Playback, defect)

Description

[Brenda]

Attachment: delay-audio.mp4

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:121.0) Gecko/20100101 Firefox/121.0

Steps to reproduce:

I have video files (several, in mov and mp4 format) that have an intentional audio delay.

e.g. The video starts at t=0, and the audio starts at t=5s. This sort of delay is common in video output from animation tools (I work in the film industry as a software engineer) where there will be no audio track for some parts of the file.

Actual results:

These videos play correctly in Chrome, mplayer, vlc. The audio starts correctly at 5 seconds into the video.

But in Firefox it incorrectly starts the audio playing immediately, at 0 seconds.
This incorrect playback happens in Firefox on Linux, Windows, and macOS

Expected results:

I expected Firefox to obey the delayed audio start encoded into the file.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Core::Audio/Video: Playback' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Mayank Bansal]

Can confirm.
Regression range:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=fa170b66896e1972488dc85979c3df6bd3a07ae6&tochange=488a1a8b33a0c427f85d10224a2f8db913e22b16

So bug 1703812 / bug 1817997

Comment 3

[orlionstr1]

I experience the same situation in YouTube videos on the website. Can you help me please?

https://gastroinventar.dk