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Just because a tool is command line does not mean it is off topic on Stack Overflow. For example, the compiler is a command line tool, git/svn are also command line tools, but no one would argue they need to be migrated to Super User.

Yet FFmpeg questions are said to be off topic and are often closed. However, FFmpeg is only used by programmers as a backend for their GUI programs. No one who is not a programmer uses it or knows about it.

This is an example of the command line of FFmpeg for converting videos to be compatible with Nokia 5800.

ffmpeg -i in.avi -f mp4 -vcodec libx264 -r 30 -s 640x360 -qcomp 0.6 -qmin 11 -qmax 51 -qdiff 4 -flags +loop -cmp +chroma -subq 7 -refs 6 -g 250 -keyint_min 25 -rc_eq \"blurCplx^(1-qComp)\" -sc_threshold 40 -me_range 12 -i_qfactor 0.71 -directpred 3 -f mp4 -threads 4 -strict experimental -acodec aac -ar 22050 -ab 64k -ac 2 -async 1 -crf 26 -aspect %3:%4 -y out.mp4

I really don't think that questions about something with that kind of command line can be reasonably answered on Super User.

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  • What would be an example of an on-topic question about ffmpeg?
    – Jack
    Feb 23, 2013 at 7:49
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    "FFmpeg is only used by programmers as a backend for their GUI programs. No one who is not a programmer uses it or knows about it". I have no idea where you came up with that; ffmpeg is a very commonly used tool Feb 23, 2013 at 8:10
  • I see no reason a command-line user couldn't just see those as equivalent to checkboxes, select boxes, or text fields on a GUI. It doesn't take a programmer. And what does "that kind of command line" refer to? The number of options listed? Any user who understands ls -l can iteratively learn the options. And if a user frequently uses certain options, they can document the meanings in a file. I'm a programmer, and I can never remember what those options mean without looking them up.
    – Kelvin
    Aug 9, 2013 at 20:22
  • That ffmpeg command line is WAY overcomplicated, and probably was generated by a GUI frontend. Normal people would write ffmpeg -r 30 -i in.avi -c:v libx264 -preset slow -crf 26 ...audio options... out.mp4. Most of the other settings are either a bad idea, or setting values that are already the defaults. (They're there if you need them for some very special case, but don't normally clutter up people's command lines.). -r 30 as an output option will make ffmpeg to drop/dup frames from in.avi, if it isn't already 30fps, instead of telling it that in.avi is 30fps. Jan 17, 2015 at 14:53

3 Answers 3

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FFmpeg is both on and off topic; it depends on the usage, and there is some overlap between Super User and Stack Overflow. Not to mention that a question about the usage may be applicable to both, so it ends up being a big gray area.

But in short, it is just a tool, but not one specifically reserved for programmers. I have used it myself in more cases as a user than as a developer, and the times I have written a front end for it, my programming questions related to it are to its usage and not unique to programming with it.

But here's my take:

  • Using FFmpeg.exe via CLI → off-topic for SO, on-topic for SU
  • Developing applications using FFmpeg.exe and writing scripts to automate its usage → on-topic for both, but more on-topic for SU
  • Developing and contributing to the FFmpeg source → on-topic for SO, off-topic for SU

There have been numerous attempts to propose new sites that deal with FFMPEG, either as the sole purpose of the site, or as a related aspect to the scope, however only Audio-Video Production has made it out of the proposal stage and to a Beta site.

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    I added Video Production, which also have a small amount of FFmpeg questions, and they're definitely on topic there as well.
    – slhck
    Feb 23, 2013 at 8:09
  • @slhck I must have missed the beta sites when I went through and signed up for the related sites, thanks. I'm going to go look through that one now. Feb 23, 2013 at 8:11
  • My experience on video.stackexchange.com has been that a lot of ffmpeg type of questions didn't get great answers. I think they would have gotten better answers on superuser. avp as a separate site cuts off non-techie video recording / editting people from ffmpeg and codec knowledgeable people who mostly just stay on superuser. e.g. still waiting for a useful answer to video.stackexchange.com/questions/14529/…, but I hear cross-posting is bad, so I haven't resorted to that yet. Jan 17, 2015 at 15:01
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    @PeterCordes I may be in the minority on this, but I see cross posting differently... just asking the same question on 2 different sites, completely customized for each site (i.e. do not copy and paste) is fine, especially if you do not do it at the same time. Ask on one, if you don't get an answer, ask on the other. I don't really understand the mania against asking a question in the hopes getting an answer from 2 different communities. Jan 17, 2015 at 15:04
  • TYVM, I just came to meta to research if xposting was ok. :) That explanation makes a lot of sense; Any site will have people that will spot badly worded questions, so it'd be fine if everyone did that. We wouldn't suddenly have 5x the amount of bad questions scattered everywhere. Jan 17, 2015 at 15:12
  • I think my question could be asked literally unchanged on SU, maybe just replace some of the details of what I did with the camera to a link back to original on avp? Jan 17, 2015 at 15:15
  • @PeterCordes Honestly, your question was too long to read over quickly. But if you think it is written so that a computer "expert" can understand and respond to it, rather than a video "expert", then it is probably fine. But again, my opinion on this may be in the minority. I don't see it as bad as some members of the community appear to. Jan 17, 2015 at 15:25
  • Yeah, I didn't expect you to read it all. :P I see lots of questions that aren't nearly specific enough, and people trying to answer have to guess what the asker REALLY needs. So I went full-retard the other direction. Since my goal is for someone to tell me which of 11 open source video editting programs can do the exact task I need to do, I felt I needed to be specific. :P I could ask on AskUbuntu, too, esp. since I literally am using Ubuntu, but I'll go with SU first. Thanks again. Jan 17, 2015 at 15:28
  • @PeterCordes I'm sorry for not reading through it more, but if you are asking for recommending which tool to use, then SuperUser is not the place. Jan 17, 2015 at 15:33
  • Yeah, the question just explains why I want to do what I'm asking, and asks for a software recommendation. Then maybe softwarerecs.stackexchange.com, or askubuntu? Thanks again for catching my mistake before I posted a question on SU that didn't belong there. I was just aiming to not waste my time apt-get installing each of the 11, and then looking carefully to see if the features I want are really missing, or I'm just not finding it. I'll probably just use audacity + ffmpeg for the tricky part at this point. >.< Jan 17, 2015 at 15:52
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We have over 500 questions on FFmpeg (command line) on Super User.

We currently have a small, but very active community of FFmpeg experts here, and most of the questions are answered within less than a day. All those people, including me, are fairly involved with the FFmpeg project itself as well.

ffmpeg is only used by programmers as a backend for their GUI programs. No one who is not a programmer uses it or knows about it.

So, no programmer has ever converted a video? I'm not really a programmer. When I use FFmpeg, I do it for my research, or fun things. For example, uploading things to YouTube. Making animated kitty GIFs from my phone's video.

But I definitely never used it for programming.

In fact, you can program with FFmpeg, even without using its command line interface. Here's an example. All questions related to that should of course belong on Stack Overflow. They have nothing to do with Super User.

Yet ffmpeg questions are said to be offtopic and are often closed

If the questions are closed, they're probably too vague. We'll happily take any FFmpeg question on Super User if it fulfills the following criteria:

  • It explains what the OP needs to achieve
  • It contains the full, uncut FFmpeg console output

Nothing more needed—the same quality rules apply everywhere. That being said, if you see a good question closed, consider bringing it to moderator attention to have it reopened or migrated.

I really don't think that questions about something with that kind of command line can be reasonably answered on SuperUser.

I really think you should check this yourself before making such bold claims.

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  • +1 for mentioning the C API. Questions regarding it would definitely belong on SO and not SU. I agree that non-programmers can use command-line just fine.
    – Kelvin
    Aug 9, 2013 at 20:15
  • By "check this yourself" I presume you mean, come over to SU and see for yourself :)
    – Kelvin
    Aug 9, 2013 at 20:26
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I've been responsible for responding to moderator flags on those questions (though I'm certainly not the only one), and here's how I decide whether a question based on that is off topic:

The problem with ffmpeg is that it does have applications outside of software development, as it says on its wikipedia page:

  • ffmpeg is a command-line tool to convert one video file format to another. It can also grab and encode in real-time from a TV card.

Here are some other issues:

  • Nothing written about ffmpeg claims its usage is unique to the programming industry.

  • It's not a programming language. It's a tool. You may interact with it through the command line, but I can also use many applications through the command line, and their usage are decidedly not unique to programmers (ping, traceroute, pretty much any network tool)

If a question asks how ffmpeg can be automated through a scripting language or how interaction with it can be automated, then that would fall into a question on topic for Stack Overflow (as would any question along those lines, so long as the goal was to program a solution).

If you have any examples of ffmpeg questions that has been closed that fall within the guidelines of a question that should stay on the site (as I mentioned above), please flag them for moderator attention and we'll take a look at them.

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