Bug#655683: libav-tools: should provide ff* compatibility symlinks

[Reinhard Tartler]

On Sa, Jan 14, 2012 at 11:13:10 (CET), Rogério Brito wrote:

> Hi there.
>
> On Jan 13 2012, Reinhard Tartler wrote:
>> Oh, I wasn't aware that we have frontends that directly use ffserver and
>> ffplay. I was only aware of front-ends for /usr/bin/ffmpeg, which is still
>> provided.
>
> Hey, I use/used ffprobe a lot (personally). Now, with mediainfo, I tend to
> use it less, but we can't count on it being in as many places/installations
> as is the case with ffmpeg.
>
>> Do you have a list of packages that rely on
>> /usr/bin/ff{play,server,probe}, so that we can file bugreports against
>> them?
>
> With the youtube-dl maintainer hat on, it will be annoying to have to
> substitute ffprobe from the script, without an easy way of changing stuff.

It's just replacing the call from 'ffprobe' to 'avprobe', after
all. What's so annoying about that?

> Actually the necessities of youtube-dl are very basic (detecting if a given
> audio track is in the file that was just downloaded from the video services
> that youtube-dl supports).
>
> If there is any documentation meant for upstreams here (well, last time I
> checked, I was the 3rd most active committer of the project), I will gladly
> update things, but one of the main youtube-dl purposes of youtube-dl is to
> be as universal (OK, with some limitations) with respect to the
> architectures and operating systems that it supports.

Well, then check if /usr/bin/avprobe exists, and if it doesn't, fall
back to ffprobe.

> We use ffprobe to detect the audio and ffmpeg to strip the video part (for
> those that want that). That is used by *many* projects, like all the
> packagings in Linux, BSDs, and MacOS X "addons", like fink (a debian-like
> system that I think that could be better if it didn't compile everything
> from sources, macports, and Homebrew).
>
> There may be people using even weirder systems that have reported success
> with youtube-dl and the team prouds itself of supporting as many systems as
> feasible.
>
> With that said, are there any *recommended* way of using ffmpeg?

Link against libavcodec and use its API. I don't think there were any
behavioral guarantees on the binaries made ever. It's not like we would
have fun to break existing applications, though.

>      ffprobe -show_streams
>
> is very convenient to parse (it's mostly key-value pairs), while something
> like
>
>      ffmpeg -i input_file.mp4 -vn -an -sn
>
> is harder.

Yeah, the output avprobe is certainly easier to parse. Still, if you
need to do that programatically, I'd recommend using libavcodec
directly.

Cheers,
Reinhard

-- 
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4