Unable to integrate ffmpeg as a native dependency for an Android NDK project

Question

I have an Android NDK project which consists entirely of C/C++ code, and it basically processes images without using any external libraries.

I'm using Android Studio + Gradle NDK Experimental plugin (0.7.0-alpha1).

Now, I need to integrate ffmpeg as a native library to use it from the C/C++ code in order to decode a H.264 video frame.

These are the questions I've found here regarding this issue:

Android - Integrating ffmpeg and android-ndk-r9c

Android NDK w/ ffmpeg library - error running project

Using FFmpeg native libraries with Android-NDK

Can not build with prebuilt static libraries using gradle-experimental

Here is my build.gradle file:

apply plugin: 'com.android.model.application'

def ffmpeg_path = file(project(':ffmpeg').projectDir).absolutePath + "/ffmpeg-android"

model {

    repositories {
        libs(PrebuiltLibraries) {
            libavcodec {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libavcodec.a")
                }
            }
            libavutil {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libavutil.a")
                }
            }
            libswresample {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libswresample.a")
                }
            }
            libswscale {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libswscale.a")
                }
            }
            libavformat {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libavformat.a")
                }
            }
            libavdevice {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libavdevice.a")
                }
            }
            libavfilter {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libavfilter.a")
                }
            }
            libpostproc {
                headers.srcDir "${ffmpeg_path}/include"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("${ffmpeg_path}/${targetPlatform.getName()}/lib/libpostproc.a")
                }
            }
        }
    }

    android {
        compileSdkVersion = 23
        buildToolsVersion = "23.0.2"

        defaultConfig.with {
            applicationId = "com.example.hellojni"
            minSdkVersion.apiLevel = 4
            targetSdkVersion.apiLevel = 23
        }
    }

    /*
     * native build settings
     */
    android.ndk {
        moduleName = "hello-jni"
        platformVersion = 9 //same as minSdkVersion.apiLevel for better compatibility
        stl    = "c++_static"
        abiFilters.addAll(["armeabi", "armeabi-v7a", "x86"]) //filtering ABIs on the ones Google Play Games library is compatible with.
    }
    android.buildTypes {
        release {
            minifyEnabled = false
            proguardFiles.add(file('proguard-rules.txt'))
        }
    }

    android.sources {
        main {
            jni {
                dependencies {
                    library "libavcodec" linkage "static"
                    library "libavutil" linkage "static"
                    library "libswresample" linkage "static"
                    library "libswscale" linkage "static"
                    library "libavformat" linkage "static"
                    library "libavdevice" linkage "static"
                    library "libavfilter" linkage "static"
                    library "libpostproc" linkage "static"
                }
            }
        }
    }

}

I based on this sample from Google which integrates an external native library.

This is the ffmpeg project I compiled before importing it into mine: https://github.com/WritingMinds/ffmpeg-android

I've added all the .a and .h files and I'm able to import the headers in my C/C++ code, but when I try to compile it I get the following error:

/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function try_decode_frame: error: undefined reference to 'avpriv_h264_has_num_reorder_frames'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function compute_pkt_fields: error: undefined reference to 'avpriv_h264_has_num_reorder_frames'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function parse_packet: error: undefined reference to 'av_parser_parse2'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function parse_packet: error: undefined reference to 'av_parser_close'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function read_frame_internal: error: undefined reference to 'av_parser_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function avformat_find_stream_info: error: undefined reference to 'av_parser_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function avformat_find_stream_info: error: undefined reference to 'avcodec_pix_fmt_to_codec_tag'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function avformat_find_stream_info: error: undefined reference to 'avpriv_get_raw_pix_fmt_tags'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function ff_stream_add_bitstream_filter: error: undefined reference to 'av_bitstream_filter_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function ff_stream_add_bitstream_filter: error: undefined reference to 'av_bitstream_filter_close'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(utils.o):utils.c:function av_apply_bitstream_filters: error: undefined reference to 'av_bitstream_filter_filter'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(aadec.o):aadec.c:function aa_read_packet: error: undefined reference to 'av_tea_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(aadec.o):aadec.c:function aa_read_packet: error: undefined reference to 'av_tea_crypt'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(aadec.o):aadec.c:function aa_read_header: error: undefined reference to 'av_tea_alloc'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(aadec.o):aadec.c:function aa_read_header: error: undefined reference to 'av_tea_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(aadec.o):aadec.c:function aa_read_header: error: undefined reference to 'av_tea_crypt'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(ac3dec.o):ac3dec.c:function ac3_eac3_probe.isra.0: error: undefined reference to 'avpriv_ac3_parse_header'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(adtsenc.o):adtsenc.c:function adts_write_header: error: undefined reference to 'avpriv_mpeg4audio_get_config'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(adtsenc.o):adtsenc.c:function adts_write_header: error: undefined reference to 'avpriv_copy_pce_data'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(asfcrypt.o):asfcrypt.c:function ff_asfcrypt_dec: error: undefined reference to 'av_rc4_alloc'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(asfcrypt.o):asfcrypt.c:function ff_asfcrypt_dec: error: undefined reference to 'av_rc4_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(asfcrypt.o):asfcrypt.c:function ff_asfcrypt_dec: error: undefined reference to 'av_rc4_crypt'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(asfcrypt.o):asfcrypt.c:function ff_asfcrypt_dec: error: undefined reference to 'av_rc4_init'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(asfcrypt.o):asfcrypt.c:function ff_asfcrypt_dec: error: undefined reference to 'av_rc4_crypt'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(matroska.o):matroska.c:function ff_mkv_stereo3d_conv: error: undefined reference to 'av_stereo3d_alloc'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(nut.o):nut.c:function ff_nut_add_sp: error: undefined reference to 'av_tree_node_alloc'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(nut.o):nut.c:function ff_nut_add_sp: error: undefined reference to 'av_tree_insert'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(nut.o):nut.c:function ff_nut_free_sp: error: undefined reference to 'av_tree_enumerate'
/Users/marcos/Documents/Android/fdecoder/ffmpeg/ffmpeg-android/armeabi-v7a/lib/libavformat.a(nut.o):nut.c:function ff_nut_free_sp: error: undefined reference to 'av_tree_destroy'
Error:error: ld returned 1 exit status
Error:Execution failed for task ':app:linkHello-jniArmeabi-v7aDebugSharedLibrary'.
> A build operation failed.
      Linker failed while linking libhello-jni.so.
  See the complete log at: file:///Users/marcos/Documents/Android/fdecoder/app/build/tmp/linkHello-jniArmeabi-v7aDebugSharedLibrary/output.txt
Information:BUILD FAILED
Information:Total time: 14.993 secs
Information:2 errors
Information:0 warnings
Information:See complete output in console

There's obviously something I'm not importing properly, but can't figure exactly what's missing.

The order of libs in the `dependencies` section matters. You should push avcodec and avutils to the end of the list — Alex Cohn, Apr 24 '16 at 21:02
@AlexCohn Makes sense, I'll try that and let you know how it went. Thanks! — mmark, May 02 '16 at 13:48

score 0 · Answer 1 · answered Feb 28 '19 at 11:09

The Makefile below works for me. (corresonds to this code)

target:muxing

CXX = g++ 
# default rules
# compile:  $(CXX) $(CPPFLAGS) -c
# link:     $(CC) $(LDFLAGS) <n>.o $(LOADLIBES) $(LDLIBS)
FFMPEG_PATH += ./ffmpeg-2.8.15/lib/ LDFLIBS += $(addprefix ${FFMPEG_PATH}, \
           libavdevice.a \
           libyasm.a \
           libavfilter.a \
           libpostproc.a \
           libavformat.a \
           libswresample.a \
           libswscale.a \
           libavcodec.a \
           libavutil.a \
           libmp3lame.a \
           libfdk-aac.a \
           libx264.a \
           ) 
LDFLIBS += -lpthread -lcrypto -lz -lssl -ldl INCS += $(addprefix -I, ./ffmpeg-2.8.15/include/)    
CFLAGS = ${INCS} CPPFLAGS = ${CFLAGS}

muxing: muxing.o
    ${CXX} ${CPPFLAGS} $^ -o $@ ${LDFLIBS}


.PHONY:clean clean:
    rm -f muxing.o muxing

Unable to integrate ffmpeg as a native dependency for an Android NDK project

1 Answers1