Re: [FFmpeg-user] How can I see what version of a library is linked? (e.g. libmp3lame)
On 2018-06-12 at 4:11 AM EDT, Carl Eugen Hoyos wrote: 2018-06-12 4:42 GMT+02:00, Zak : These two questions cannot be answered by ffmpeg, by any executable, I suspect security considerations are among the reasons why this is impossible. Iirc, ldd does not work on osx, "otool -L ffmpeg" will tell you. Version information (that may not be available for all external libs but certainly for some) is a missing feature. Carl Eugen Yes, the following works on MacOS: bash$ otool -L /path/to/ffmpeg /usr/lib/libbz2.1.0.dylib (compatibility version 1.0.0, current version 1.0.5) /usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.5) # ...snip... By default, it follows symlinks all the way to a real file, and it prints the compatibility version and current version, which is nice. I can't figure out how to see what the executable actually requires, in the case where it was given a newer version than it requires. So it loads libz.1.dylib verson 1.2.5, but what version does FFmpeg really NEED? Is 1.0.0 good enough? Or does FFmpeg need >= 1.1.0? Or >= 1.2.0? Does the FFmpeg executable actually include such specific information, or will it fail if and when it looks up a symbol and can't find it? I have this question about otool on MacOS and also ldd on Linux. Sad note: libmp3lame is not dynamically linked by FFmpeg on either my Mac or my Kubuntu box. It must be statically linked, which means the version information is lost - unless I disassemble ffmpeg or something. On Kubuntu, the default behavior of GNU ld should be to use the dynamic link version if possible (I think), and it is possible to dynamically link libmp3lame.so. I may try recompiling FFmpeg and looking for the linker call with something like -lmp3lame or -llibmp3lame, and see if it is preceded by an instruction to statically link it. It looks like Danny Mitchell's compiled version of ffmpeg also has libmp3lame statically linked, or else it doesn't have it at all. And Danny Mitchell's ldd ffmpeg output lists a large number of dynamically linked libraries that I didn't enable or link in any way, so I'm guessing the MP3 encoder was not disabled. But maybe it was disabled. My ffmpeg only has one MP3 encoder (libmp3lame), although it seems to have possibly up to six decoders (I don't know whether to count MP3onMP4, for instance). I am unaware of any MP3 encoder aside from libmp3lame that is supported by FFmpeg, and I don't see any on that ldd output from Danny Mitchell. It would be nice for FFmpeg to record the versions of statically linked libraries, but it looks like it would be hard. Zak ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] How can I see what version of a library is linked? (e.g. libmp3lame)
On 12/06/2018, Zak wrote:
> Dear FFmpeg User Mailing List,
>
> The versions of certain libraries are printed in the banner, such as
> libavcodec.
>
> I am curious how to find information about linked libraries, such as
> libmp3lame, the LAME MP3 encoder. I would like to know:
>
> 1. Was it statically or dynamically linked?
>
> 2. If dynamically linked, where is the libmp3lame.so file?
>
> (I think the answer is /usr/local/libmp3lame.dylib in my case on my Mac,
> but I want FFmpeg to tell me. I am not on Kubuntu right now, but I can
> probably find it on Kubuntu also, and I'm guessing it is an .so and not
> a .dylib file on that OS.)
>
> 3. What is the version of the linked library? Here is how I can ask LAME
> itself, from the LAME CLI front-end for libmp3lame:
>
> bash$ lame --version
>
> LAME 64bits version 3.100 (http://lame.sf.net)
>
> -
>
> Here is my best guess:
>
> bash$ ffmpeg -h encoder=libmp3lame
>
> Encoder libmp3lame [libmp3lame MP3 (MPEG audio layer 3)]:
> General capabilities: delay small
> Threading capabilities: none
> Supported sample rates: 44100 48000 32000 22050 24000 16000 11025
> 12000 8000
> Supported sample formats: s32p fltp s16p
> Supported channel layouts: mono stereo
> libmp3lame encoder AVOptions:
>-reservoir E...A... use bit reservoir (default true)
>-joint_stereo E...A... use joint stereo (default true)
>-abr E...A... use ABR (default false)
>
> This looks promising, but it turns out all of that information is
> hardcoded in this file:
>
> ffmpeg/libavcodec/libmp3lame.c
>
> You can even change this string:
>
> AVCodec ff_libmp3lame_encoder = {
>// ...snip...
>.long_name = "libmp3lame MP3 (MPEG audio layer 3)"
>
> ...and the FFmpeg help will display whatever you type. It is not pulling
> it from the library.
>
> This is intended to be a general question, so I am not going to include
> a specific FFmpeg banner because I use FFmpeg on two operating systems
> (MacOS 10.12 and Kubuntu) and I have multiple versions of FFmpeg.
>
> Thank you,
>
> Zak F.
> ___
> ffmpeg-user mailing list
> ffmpeg-user@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
If you're on a Unix-like system (including MacOS and *Ubuntu) use
ldd
where is the path to the executable you want to examine. Example:
$ ldd /usr/local/bin/ffmpeg
linux-vdso.so.1 => (0x7fff279ff000)
libavdevice.so.55 => /usr/local/lib/libavdevice.so.55
(0x2ac9b97e7000)
libavfilter.so.4 => /usr/local/lib/libavfilter.so.4 (0x2ac9b99fe000)
libavformat.so.55 => /usr/local/lib/libavformat.so.55
(0x2ac9b9cdf000)
libavcodec.so.55 => /usr/local/lib/libavcodec.so.55 (0x2ac9ba085000)
libswresample.so.0 => /usr/local/lib/libswresample.so.0
(0x2ac9bb1f)
libswscale.so.2 => /usr/local/lib/libswscale.so.2 (0x2ac9bb407000)
libavutil.so.52 => /usr/local/lib/libavutil.so.52 (0x2ac9bb67d000)
libX11.so.6 => /usr/lib/libX11.so.6 (0x2ac9bb8d3000)
libpthread.so.0 => /lib/libpthread.so.0 (0x2ac9bbcb1000)
libm.so.6 => /lib/libm.so.6 (0x2ac9bbecd000)
libvdpau.so.1 => /usr/lib/libvdpau.so.1 (0x2ac9bc15)
libc.so.6 => /lib/libc.so.6 (0x2ac9bc351000)
libXv.so.1 => /usr/lib/libXv.so.1 (0x2ac9bc6b3000)
libXext.so.6 => /usr/lib/libXext.so.6 (0x2ac9bc8b9000)
libjack.so.0 => /usr/lib/libjack.so.0 (0x2ac9bcacb000)
libasound.so.2 => /usr/lib/libasound.so.2 (0x2ac9bcd0e000)
libSDL-1.2.so.0 => /usr/lib/libSDL-1.2.so.0 (0x2ac9bcff4000)
libdc1394.so.22 => /usr/lib/libdc1394.so.22 (0x2ac9bd2ad000)
libssl.so.0.9.8 => /usr/lib/libssl.so.0.9.8 (0x2ac9bd522000)
libcrypto.so.0.9.8 => /usr/lib/libcrypto.so.0.9.8 (0x2ac9bd778000)
libbz2.so.1.0 => /lib/libbz2.so.1.0 (0x2ac9bdb19000)
libz.so.1 => /usr/lib/libz.so.1 (0x2ac9bdd29000)
libva.so.1 => /usr/lib/libva.so.1 (0x2ac9bdf4)
libvorbisenc.so.2 => /usr/lib/libvorbisenc.so.2 (0x2ac9be146000)
libvorbis.so.0 => /usr/lib/libvorbis.so.0 (0x2ac9be416000)
libtheoraenc.so.1 => /usr/lib/libtheoraenc.so.1 (0x2ac9be447000)
libtheoradec.so.1 => /usr/lib/libtheoradec.so.1 (0x2ac9be686000)
libspeex.so.1 => /usr/lib/libspeex.so.1 (0x2ac9be89f000)
libschroedinger-1.0.so.0 => /usr/lib/libschroedinger-1.0.so.0
(0x2ac9beab9000)
libopenjpeg.so.2 => /usr/lib/libopenjpeg.so.2 (0x2ac9bed63000)
libgsm.so.1 => /usr/lib/libgsm.so.1 (0x2ac9bef83000)
librt.so.1 => /lib/librt.so.1 (0x2ac9bf191000)
libxcb.so.1 => /usr/lib/libxcb.so.1 (0x2ac9bf399000)
libdl.so.2 => /lib/libdl.so.2
