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• Undefined symbol despite libraries being linked

  17 septembre 2020, par Areopag

  currently I'm trying to write a JNI function using ffmpeg features, but when I'm trying to run my java executable after a clean compile I get the following error :

  


  /usr/lib/jvm/java-1.11.0-openjdk-amd64/bin/java: symbol lookup error: /lib/libmediaserv_ffmpeg.so: undefined symbol: _Z19avformat_open_inputPP15AVFormatContextPKcP13AVInputFormatPP12AVDictionary


  


  I can't figure out why ffmpeg is not linked correctly.

  


  mediaserv_ffmpeg.cpp :

  


  #include <iostream>&#xA;#include <libavformat></libavformat>avformat.h>&#xA;#include <libavutil></libavutil>avutil.h>&#xA;&#xA;JNIEXPORT jobject JNICALL Java_mediaserv_ffmpeg_getMetadata&#xA;        (JNIEnv* env, jclass cls, jstring path) { ... }&#xA;</iostream>

  


  What I've tried so far is inspecting libmediaserv_ffmpeg.so :

  


   nm libmediaserv_ffmpeg.so --format=sysv | grep avformat
_Z19avformat_open_inputPP15AVFormatContextPKcP13AVInputFormatPP12AVDictionary|                |   U  |            NOTYPE|                |     |*UND*
_Z20avformat_close_inputPP15AVFormatContext|                |   U  |            NOTYPE|                |     |*UND*
_Z25avformat_find_stream_infoP15AVFormatContextPP12AVDictionary|                |   U  |            NOTYPE|                |     |*UND*


  


  Which, I think, is just another way of saying that there are undefined symbols in the .so file.

  


  The commands used to build the lib (taken from make VERBOSE=1) :

  


  /usr/bin/c++  -Dmediaserv_ffmpeg_EXPORTS -I/usr/lib/jvm/java-11-openjdk-amd64/include -I/usr/lib/jvm/java-11-openjdk-amd64/include/linux -I/mnt/g/Workspace/mediaserv/third-party/ffmpeg  -fPIC   -std=gnu++1z -o CMakeFiles/mediaserv_ffmpeg.dir/mediaserv_ffmpeg.cpp.o -c /mnt/g/Workspace/mediaserv/third-party/mediaserv_ffmpeg.cpp
/usr/bin/c++ -fPIC   -shared -Wl,-soname,libmediaserv_ffmpeg.so -o /mnt/g/Workspace/mediaserv/build/libs/libmediaserv_ffmpeg.so CMakeFiles/mediaserv_ffmpeg.dir/mediaserv_ffmpeg.cpp.o  -Wl,-rpath,/usr/lib/jvm/java-11-openjdk-amd64/lib:/usr/lib/jvm/java-11-openjdk-amd64/lib/server:/mnt/g/Workspace/mediaserv/third-party/ffmpeg/libavutil:/mnt/g/Workspace/mediaserv/third-party/ffmpeg/libavformat /usr/lib/jvm/java-11-openjdk-amd64/lib/libjawt.so /usr/lib/jvm/java-11-openjdk-amd64/lib/server/libjvm.so ../ffmpeg/libavutil/libavutil.so ../ffmpeg/libavformat/libavformat.so


  


  I've already tried to seek for errors in GCC's trace option for the linker and it lists me which libraries it tries to link / is linking but the result stays the same.

  


  /usr/bin/ld: mode elf_x86_64
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/crti.o
/usr/lib/gcc/x86_64-linux-gnu/7/crtbeginS.o
CMakeFiles/mediaserv_ffmpeg.dir/mediaserv_ffmpeg.cpp.o
/usr/lib/jvm/java-11-openjdk-amd64/lib/libjawt.so
/usr/lib/jvm/java-11-openjdk-amd64/lib/server/libjvm.so
../ffmpeg/libavutil/libavutil.so
../ffmpeg/libavformat/libavformat.so
-lstdc++ (/usr/lib/gcc/x86_64-linux-gnu/7/libstdc++.so)
/lib/x86_64-linux-gnu/libm.so.6
/lib/x86_64-linux-gnu/libmvec.so.1
libgcc_s.so.1 (/usr/lib/gcc/x86_64-linux-gnu/7/libgcc_s.so.1)
/lib/x86_64-linux-gnu/libc.so.6
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
libgcc_s.so.1 (/usr/lib/gcc/x86_64-linux-gnu/7/libgcc_s.so.1)
/usr/lib/gcc/x86_64-linux-gnu/7/crtendS.o
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/crtn.o


  


  CMakeLists.txt :

  


  cmake_minimum_required(VERSION 3.17)
project(mediaserv_ffmpeg)

set(CMAKE_CXX_STANDARD 17)
set(BUILD_SHARED_LIBS ON)
add_library(${PROJECT_NAME} SHARED mediaserv_ffmpeg.cpp mediaserv_ffmpeg.h)

find_package(JNI REQUIRED)

find_path(AVUTIL_INCLUDE_DIR libavutil/avutil.h HINTS ffmpeg REQUIRED)
find_library(AVUTIL_LIBRARY avutil HINTS ${PROJECT_SOURCE_DIR}/ffmpeg/libavutil PATHS REQUIRED)

find_path(AVFORMAT_INCLUDE_DIR libavformat/avformat.h HINTS ffmpeg REQUIRED)
find_library(AVFORMAT_LIBRARY avformat HINTS ${PROJECT_SOURCE_DIR}/ffmpeg/libavformat REQUIRED)

target_include_directories(${PROJECT_NAME} PRIVATE ${JNI_INCLUDE_DIRS} ${AVUTIL_INCLUDE_DIR} ${AVFORMAT_INCLUDE_DIR})

target_link_libraries(${PROJECT_NAME} ${JNI_LIBRARIES} ${AVUTIL_LIBRARY} ${AVFORMAT_LIBRARY})


  


  Neither ffmpeg taken from the official ubuntu bionic repository nor a self-compiled version with configure --enable-shared works for me.

  


  Where is my mistake or what could I still inspect ?

  


  Thanks in advance.

  


• ffmpeg : Overlay audios with different lengths using amix and apad

  23 novembre 2017, par Valdir

  I’m trying to overlay two audio files with the following command :

  ffmpeg -y -i mp3/test1.mp3 -i mp3/test2.mp3 -filter_complex "[0:0][1:0] amix=inputs=2:duration=longest" -c:a libmp3lame merged.mp3

  But it fails if the length of the audios are different :

  ffmpeg -y -i live.mp3 -i mp3/test1.mp3 -filter_complex "[0:0][1:0] amix=inputs=2:duration=longest" -c:a libmp3lame merged2.mp3
  
  ffmpeg version 2.8.11-0ubuntu0.16.04.1 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  
    configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  
    libavutil      54. 31.100 / 54. 31.100
  
    libavcodec     56. 60.100 / 56. 60.100
  
    libavformat    56. 40.101 / 56. 40.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 40.101 /  5. 40.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.101 /  1.  2.101
  
    libpostproc    53.  3.100 / 53.  3.100
  
  [mp3 @ 0x22cf760] Format mp3 detected only with low score of 1, misdetection possible!
  
  [mp3 @ 0x22cf760] Could not find codec parameters for stream 0 (Audio: mp3, 0 channels, s16p): unspecified frame size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  live.mp3: could not find codec parameters
  
  Input #0, mp3, from 'live.mp3':
  
    Duration: N/A, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Audio: mp3, 0 channels, s16p
  
  [mp3 @ 0x22d10a0] Skipping 0 bytes of junk at 18034.
  
  Input #1, mp3, from 'mp3/test1.mp3':
  
    Metadata:
  
      title           : Nothing Else Matters [Official Music Video]
  
      artist          : Metallica
  
    Duration: 00:06:25.80, start: 0.025057, bitrate: 192 kb/s
  
      Stream #1:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
  
      Metadata:
  
        encoder         : Lavc56.14
  
  [abuffer @ 0x22fa2c0] Value inf for parameter 'time_base' out of range [0 - 2.14748e+09]
  
      Last message repeated 3 times
  
  [abuffer @ 0x22fa2c0] Error setting option time_base to value 1/0.
  
  [graph 0 input from stream 0:0 @ 0x22fa3e0] Error applying options to the filter.
  
  Error configuring complex filters.
  
  Numerical result out of range

  How do I add the apad filter so that silence is added to the shortest audio ?

• Is FFmpegAudioDecoder supposed to reinitialize upon append of new init segment

  14 novembre 2023, par martin

  I am attempting to switch audio tracks but when switching the FFmpegAudioDecoder never reinitializes like it does with video tracks of differing resolutions. I am not certain if this is the intended behavior of FFmpegAudioDecoder and would love to learn more about the expected behavior.

  


  When switching audio tracks I end up calling the following operations :

  


  if sourceBuffer.getIsUpdate() {sourceBuffer.abort()}
sourceBuffer.remove(0-videoDuration)
initSegmentDataStream = fetch init segment of new audio representation
sourceBuffer.appendBuffer(initSegmentDataStream)


  


  These are the Media tab messages from initial video load

  


  ChunkDemuxer
Selected FFmpegAudioDecoder for audio decoding, config: codec: aac, profile: unknown, bytes_per_channel: 2, channel_layout: STEREO, channels: 2, samples_per_second: 48000, sample_format: Signed 16-bit, bytes_per_frame: 4, seek_preroll: 0us, codec_delay: 0, has extra data: false, encryption scheme: Unencrypted, discard decoder delay: false, target_output_channel_layout: STEREO, target_output_sample_format: Unknown sample format, has aac extra data: true
Cannot select DecryptingVideoDecoder for video decoding
Cannot select VDAVideoDecoder for video decoding
Cannot select VpxVideoDecoder for video decoding
Selected Dav1dVideoDecoder for video decoding, config: codec: av1, profile: av1 profile main, level: not available, alpha_mode: is_opaque, coded size: [1280,720], visible rect: [0,0,1280,720], natural size: [1280,720], has extra data: false, encryption scheme: Unencrypted, rotation: 0°, flipped: 0, color space: {primaries:BT709, transfer:BT709, matrix:BT709, range:LIMITED}
Dropping audio frame (DTS 0us PTS -105375us,-62709us) that is outside append window [0us,9223372036854775807us).
Dropping audio frame (DTS 42666us PTS -62708us,-20042us) that is outside append window [0us,9223372036854775807us).
Truncating audio buffer which overlaps append window start. PTS -20041us frame_end_timestamp 22625us append_window_start 0us
Effective playback rate changed from 0 to 1


  


  For comparison this is what I get when appending the init segment of a different video resolution / track

  


  video decoder config changed midstream, new config: codec: av1, profile: av1 profile main, level: not available, alpha_mode: is_opaque, coded size: [1920,1080], visible rect: [0,0,1920,1080], natural size: [1920,1080], has extra data: false, encryption scheme: Unencrypted, rotation: 0°, flipped: 0, color space: {primaries:BT709, transfer:BT709, matrix:BT709, range:LIMITED}



  


  Chrome version : Version 119.0.6045.123 (Official Build)

  


  When appending the new init segment of an audio track I was expecting the FFmpegAudioDecoder to be reinitialized like the Dav1dVideoDecoder does for video tracks