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Hi,I am currently doing a real time video encoding c program using ffmpeg, initially I encountered a lot of "undefined reference" error, after I set the linker in build options, some error got disappeared, but still some error remains.

||=== Build: Debug in c_3rd party encoding (compiler: GNU GCC Compiler)     ===|
/home/yonghao/codeblocksfile/c_3rd party encoding/main.c||In function     ‘init_video_encode’:|
/home/yonghao/codeblocksfile/c_3rd party encoding/main.c|73|warning: ‘avcodec_alloc_frame’ is deprecated (declared at ../../ffmpeg_build/include/libavcodec/avcodec.h:3618) [-Wdeprecated-declarations]|
/home/yonghao/codeblocksfile/c_3rd party encoding/main.c||In function ‘cancle_encode’:|
/home/yonghao/codeblocksfile/c_3rd party encoding/main.c|134|warning: ‘avcodec_free_frame’ is deprecated (declared at ../../ffmpeg_build/include/libavcodec/avcodec.h:3643) [-Wdeprecated-declarations]|
/home/yonghao/codeblocksfile/c_3rd party encoding/main.c|21|warning: ‘endcode’ defined but not used [-Wunused-variable]|
../../ffmpeg_build/lib/libavcodec.a(libmp3lame.o)||In function `mp3lame_encode_frame':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|211|undefined reference to `lame_encode_buffer_float'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|195|undefined reference to `lame_encode_buffer'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|198|undefined reference to `lame_encode_buffer_int'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|219|undefined reference to `lame_encode_flush'|
../../ffmpeg_build/lib/libavcodec.a(libmp3lame.o)||In function `mp3lame_encode_close':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|86|undefined reference to `lame_close'|
../../ffmpeg_build/lib/libavcodec.a(libmp3lame.o)||In function `mp3lame_encode_init':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|98|undefined reference to `lame_init'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|102|undefined reference to `lame_set_num_channels'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|103|undefined reference to `lame_set_mode'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|106|undefined reference to `lame_set_in_samplerate'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|107|undefined reference to `lame_set_out_samplerate'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|111|undefined reference to `lame_set_quality'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|115|undefined reference to `lame_set_VBR'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|116|undefined reference to `lame_set_VBR_quality'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|120|undefined reference to `lame_set_VBR'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|121|undefined reference to `lame_set_VBR_mean_bitrate_kbps'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|123|undefined reference to `lame_set_brate'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|128|undefined reference to `lame_set_bWriteVbrTag'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|131|undefined reference to `lame_set_disable_reservoir'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|134|undefined reference to `lame_init_params'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|140|undefined reference to `lame_get_encoder_delay'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libmp3lame.c|143|undefined reference to `lame_get_framesize'|
../../ffmpeg_build/lib/libavcodec.a(libopusdec.o)||In function `libopus_flush':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|178|undefined reference to `opus_multistream_decoder_ctl'|
../../ffmpeg_build/lib/libavcodec.a(libopusdec.o)||In function `libopus_decode':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|143|undefined reference to `opus_multistream_decode_float'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|139|undefined reference to `opus_multistream_decode'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|148|undefined reference to `opus_strerror'|
../../ffmpeg_build/lib/libavcodec.a(libopusdec.o)||In function `libopus_decode_close':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|121|undefined reference to `opus_multistream_decoder_destroy'|
../../ffmpeg_build/lib/libavcodec.a(libopusdec.o)||In function `libopus_decode_init':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|87|undefined reference to `opus_multistream_decoder_create'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|91|undefined reference to `opus_strerror'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|97|undefined reference to `opus_multistream_decoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusdec.c|99|undefined reference to `opus_strerror'|
../../ffmpeg_build/lib/libavcodec.a(libopusenc.o)||In function `libopus_encode':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|346|undefined reference to `opus_multistream_encode'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|342|undefined reference to `opus_multistream_encode_float'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|351|undefined reference to `opus_strerror'|
../../ffmpeg_build/lib/libavcodec.a(libopusenc.o)||In function `libopus_encode_close':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|389|undefined reference to `opus_multistream_encoder_destroy'|
../../ffmpeg_build/lib/libavcodec.a(libopusenc.o)||In function `libopus_encode_init':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|254|undefined reference to `opus_multistream_encoder_create'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|260|undefined reference to `opus_strerror'|
../../ffmpeg_build/lib/libavcodec.a(libopusenc.o)||In function `libopus_configure_encoder':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|117|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|119|undefined reference to `opus_strerror'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|124|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|127|undefined reference to `opus_strerror'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|130|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|132|undefined reference to `opus_strerror'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|135|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|138|undefined reference to `opus_strerror'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|141|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|144|undefined reference to `opus_strerror'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|149|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|152|undefined reference to `opus_strerror'|
../../ffmpeg_build/lib/libavcodec.a(libopusenc.o)||In function `libopus_encode_init':|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|288|undefined reference to `opus_multistream_encoder_ctl'|
/home/yonghao/ffmpeg_sources/ffmpeg/libavcodec/libopusenc.c|290|undefined reference to `opus_strerror'|
||More errors follow but not being shown.|
||Edit the max errors limit in compiler options...|
||=== Build failed: 50 error(s), 3 warning(s) (0 minute(s), 3 second(s)) ===|

Here are my screen shot of the CodeBlock linker setting.

ffmpeg_build/lib/libvpx.a
ffmpeg_build/lib/libswscale.a
ffmpeg_build/lib/libwresample.a
ffmpeg_build/lib/libpostproc.a
ffmpeg_build/lib/libfdk-aac.a
ffmpeg_build/lib/libvutil.a
ffmpeg_build/lib/libvformat.a
ffmpeg_build/lib/libavfilter.a
ffmpeg_build/lib/libavdevice.a
ffmpeg_build/lib/libavcodec.a

Totally 10 libs.

My Questions:

  1. Are these errors caused by lacking libs or libs not linked.
  2. What libs I missing or what libs should I add to linker.
Yoohoo
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1 Answers1

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It seems to be linking order mismatched. To understand linking order please refer Why does the order in which libraries are linked sometimes cause errors in GCC?

Try the following linking order

libavdevice
libavformat
libavfilter
libavcodec
libwscale
libavutil
libswresample
libswscale
libpostproc
libavresample
Community
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