Choosing a muxer in 2.8.1

[fugueink]

I have an ancient (late 2012) MacBook Pro running Catalina (10.15.7) and AviDemux 2.8.1.

I have downloaded an audiobook from YouTube, and I want to strip out the video portion to save space. For reasons passing my understanding, although the original MP4 seems to have a good time index, all the AAC files flash weird, random time-remaining numbers when I play them in VLC.

I cannot figure out why this is so, but of course, my understanding of formats and muxers is extremely limited.

I always have the video filter set to "null" and the audio set to "AAC (lav)". I can't remember all the output muxers I've tried; MP4, MP4v2, and MKV, I definitely have.

I then choose "Save Audio" from the Audio menu. And I wait fifteen minutes or so while the file is generated. I play it in VLC, and the time-remaining display jumps randomly around. The time-played index usually seems just fine, but I prefer to have time remaining displayed.

Could someone please put me out of my pain and tell me which output muxer I should be using?

Thank you.

[fugueink]

I just tried redownloading the MP4 and creating the AAC from that. No luck on my first attempt.

On edit: just tried with video null, audio AAC(Faac), and MKV muxer. Still the same hinky results.

On second edit: null/AAC(FDK)/MP4v2 and null/Copy/MP4v2 tried. No change. Also downloaded a different audiobook and tried null/AAC(Faac)/MKV. Got the same behavior.

I do have AACs that play just fine regarding the time-remaining index.

I am, by the way, running the most recent VLC, 3.0.20.

[eumagga0x2a]

AAC is (almost always) a variable bitrate codec, therefore reliable estimation of duration and timing from bitrate is very inaccurate. Either re-encode the audio track to CBR (constant bitrate) mp3 or use ffmpeg as a tool to store the AAC stream in a MP4 container which would add timing information which is absent in a raw (ADTS encapsulated) AAC LC stream as output by Avidemux.

[fugueink]

Yikes. . . .

Well, I'm glad I fessed up to my ignorance upfront.

I think I will re-extract my audiobooks as AC3.

Thank you, eumagga0x2a!