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• Linking against ffmpeg libs on Rust gives `vdp_device_create_x11` (libvdpau-dev missing ?)

  7 octobre 2020, par Guerlando OCs

  I'm trying to link against ffmpeg libraries, in rust, and getting as the only error :

  


  undefined reference to `vdp_device_create_x11'


  


  Here's the libs linked :

  


  fn main() {
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rustc-link-lib=static=z");
    println!("cargo:rustc-link-lib=dylib=dl");
    println!("cargo:rustc-link-lib=static=X11");
    println!("cargo:rustc-link-lib=dylib=vdpau");
    println!("cargo:rustc-link-lib=dylib=va");
    println!("cargo:rustc-link-lib=dylib=va-drm");
    println!("cargo:rustc-link-lib=dylib=va-x11");
    println!("cargo:rustc-link-lib=dylib=xcb");
}


  


  On C++ I used to link with all these libs above + some for GTK and it worked. Don't know why it wont work now.

  


  On errors when compiling c code with ffmpeg library it says that I should link against -lvdpau - libvdpau-dev

  


  I tried adding

  


      println!("cargo:rustc-link-lib=dylib=vdpau-dev");


  


  but I get

  


    = note: /usr/bin/ld: cannot find -lvdpau-dev


  


  Even though I installed libvdpau-dev. Indeed,

  


  ldconfig -p | grep vdpau
        libvdpau.so.1 (libc6,x86-64) => /lib/x86_64-linux-gnu/libvdpau.so.1
        libvdpau.so (libc6,x86-64) => /lib/x86_64-linux-gnu/libvdpau.so


  


  Why libdpau-dev is missing ? I'm on ubuntu 20, apt-get install -y libdpau-dev. Finny thing is that C++ compiles perfectly in this same docker container without any modifications and without libdpau-dev

  


  UPDATE :

  


  nm -D /lib/x86_64-linux-gnu/libvdpau.so | grep x11
0000000000001d50 T vdp_device_create_x11


  


  UPDATE :

  


  note: /usr/bin/ld: /home/dev/orwell/liborwell_rust/target/debug/deps/libffmpeg_sys_next-109176c9182219d2.rlib(hwcontext_vdpau.o): in function `vdpau_device_create':
          hwcontext_vdpau.c:(.text+0x686): undefined reference to `vdp_device_create_x11'


  


  The file hwcontext_vdpau.o is from ffmpeg : https://ffmpeg.org/doxygen/trunk/hwcontext__vdpau_8c_source.html

  


  My theory of why it worked for your case but not mine is that in your case you link these libraries after the code that uses vdp_device_create_x11. In my case, I think it links my code against the libs I provided + ffmpeg libs. So maybe ffmpeg libs come after or before the libs I provided.

  


  Well, since I'm linking against the project that links with ffmpeg, I think this is what's happening :

  


  my_code is being linked against ffmpeg-sys-next crate + libs I provided. Where ffmpeg-sys-next crate contains the ffmpeg libs. I just don't know if the order is

  


  ffmpeg-sys-next crate + libs I provided

  


  or

  


  libs I provided + ffmpeg-sys-next crate.

  


  If ffmpeg needs vdp_device_create_x11, then vdp_device_create_x11 should come before ffmpeg or after ?

  


  Is it possible to control if the crate dependencies are linked after or before the libs I provided ?

  


  UPDATE :

  


  Running `rustc --crate-name liborwell_rust --edition=2018 src/main.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type bin --emit=dep-info,link -Cembed-bitcode=no -C debuginfo=2 -C metadata=a40686dab33e6453 -C extra-filename=-a40686dab33e6453 --out-dir /home/dev/orwell/liborwell_rust/target/debug/deps -C incremental=/home/dev/orwell/liborwell_rust/target/debug/incremental -L dependency=/home/dev/orwell/liborwell_rust/target/debug/deps --extern ffmpeg_next=/home/dev/orwell/liborwell_rust/target/debug/deps/libffmpeg_next-c150275f8ec2ece5.rlib --extern liborwellprofile_protobuf_rust=/home/dev/orwell/liborwell_rust/target/debug/deps/libliborwellprofile_protobuf_rust-85a803bf8441d976.rlib --extern phf=/home/dev/orwell/liborwell_rust/target/debug/deps/libphf-0282e4d662343769.rlib --extern protobuf=/home/dev/orwell/liborwell_rust/target/debug/deps/libprotobuf-525fd12c456cb486.rlib -l static=z -l dylib=dl -l dylib=vdpau -l static=X11 -l dylib=va -l dylib=va-drm -l dylib=va-x11 -l dylib=xcb -L native=/home/dev/orwell/deps/ffmpeg/build/linux/x86_64/lib`


  


  Looks like the ffmpeg libraries are the last thing passed to the compiler/linker : -L native=/home/dev/orwell/deps/ffmpeg/build/linux/x86_64/lib

  


• decode raw buffer with ffmpeg av_codec_video_2

  19 décembre 2015, par will.I4M

  I’m trying to write a decoder for a webrtc app in C. I receive a RTP stream, I parse every packet, reorder them, and put the payload in a AVPacket, as described here (FFmpeg decode raw buffer with avcodec_decode_video2).
  The reordering part is not described in this link but I’m pretty sure this part is OK.

  The question is, I dont know how to give the decoder information about resolution, pix_fmt etc. Do I need to create an AVstream* and fill it with all information I took from rtp header ?

  Do someone have a piece of running code that decode a VP8 packet depacketized without the use of rtp_dec etc.?

  In this link, no more information seems to be sent to the decoder, is it able to decode without knowing resolution and without any header ?

• Anomalie #920 (En cours) : Gérer les logos comme des documents

  27 décembre 2019, par b b

  Je pense qu’on peut fermer suite à cette rafale de modifs, non ?

  r24348 r24349 r24351 r24355 r24356

  https://zone.spip.net/trac/spip-zone/changeset/116119/
  https://zone.spip.net/trac/spip-zone/changeset/116123/
  https://zone.spip.net/trac/spip-zone/changeset/116237/
  https://zone.spip.net/trac/spip-zone/changeset/116143/