Comment by zahlman
5 months ago
You appear to have linked the canonical, which has a few duplicates marked. All are asking about isolating one channel, as far as I can tell. This canonical is literally titled "ffmpeg: isolate one audio channel". One of them also asks about "downmixing" to mono after isolating the channel (which I guess means marking the audio format as mono so that that isolated channel will play on both speakers), but that is trivial. And you see the same basic techniques offered in the answers: to use `-map-channel` or the `pan` audio filter. The other one explicitly wants a panned result, i.e. still stereo but only on one side; the logic for this is clear from the explanation in the canonical answer.
The point is to show the technique, not to meet individual exact needs. Stack Overflow doesn't need separate "how do I get the second line of a file?" and "how do I get the third line of a file?" questions.
The dupe is what I linked. The orig is https://superuser.com/questions/601972
The orig wants a mono output with one of the original channels as signal source. This involves downmixing i.e. rematrixing the audio.
The dupe want to just mute one of the channels, not repan it. One can't apply map_channel to do what the dupe wants.
One can use a couple of methods to achieve the dupe, including pan. But the syntax of pan needed for the dupe case is not the same as the orig, or deducible from it. They need to consult the docs (fortuitously, the dupe case is an illustrated example) or get a direct answer. The 'technique' shown in the orig is not intuitively adaptable to the dupe - one needs to know about the implicit muting that pan applies, which is not documented or evident in the orig answer. So it's not a duplicate of the source Q.
> The dupe is what I linked. The orig is
Ah, I don't actually have a SuperUser account, so it was automatically redirecting me.
> The 'technique' shown in the orig is not intuitively adaptable to the dupe
IDK, it looks to me like I could figure it out pretty easily from what's written there, and I'm not by any means an ffmpeg expert.
> it looks to me like I could figure it out pretty easily from what's written there
Really? Wanna give it a try then, without looking up any other documentation? I've used ffmpeg plenty of times, but it doesn't seem obvious to me how I'd mute one audio channel.
From your other comments it sounds like you believe SO should have less content. Why? How would SO be improved by forcing people to figure something like this out from the existing answer? I just don't understand the benefit to having that question marked as a duplicate and deleted.
I've long wondered the same thing about wikipedia. Why does wikipedia delete well written pages about obscure topics? Is their hard disk full? Does every page cost them money? Does google search struggle at scale? I don't understand the benefit to deleting good content.
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