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Ajouter notes et légendes aux images
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Compiling c++ program for ffmpeg, error give undefined reference to [duplicate]
6 août 2020, par leonardltk1I have a code
read_mp3.cpp, which usesffmpegto decode an mp3 file into an array.

Code for
read_mp3.cppis as follows :

#include 
 #include 

 // I use extern "C" as recommended here: https://blog.csdn.net/qq_18144521/article/details/79608355
 extern "C"
 {
 #include <libavutil></libavutil>opt.h>
 #include <libavcodec></libavcodec>avcodec.h>
 #include <libavformat></libavformat>avformat.h>
 #include <libswresample></libswresample>swresample.h>
 }
 using namespace std;


 int decode_audio_file(const char* path, const int sample_rate, double** data, int* size) {
 // initialize all muxers, demuxers and protocols for libavformat
 // (does nothing if called twice during the course of one program execution)
 av_register_all();

 /*
 Code for the rest of this function is found here :
 https://rodic.fr/blog/libavcodec-tutorial-decode-audio-file/
 */

 return 0;
 }

 int main (int argc, char ** argv) {
 // decode data
 int sample_rate = 44100;
 double* data;
 int size;
 if (decode_audio_file(argv[1], sample_rate, &data, &size) != 0) {
 return -1;
 }

 /*
 Do something with data ...
 */

 return 0;
 }


I tried different ways to compilations, but to no avail :


g++ -o ./read_mp3.out -Ofast -Wall -Wextra \
 -lavformat-ffmpeg -lavdevice-ffmpeg -lavcodec-ffmpeg -lavutil -lswresample \
 -std=c++11 "./read_mp3.cpp"
 
 g++ -o ./read_mp3.out -Ofast -Wall -Wextra \
 -lavformat -lavdevice -lavcodec -lavutil -lswresample \
 -std=c++11 "./read_mp3.cpp"
 
 g++ -o ./read_mp3.out -Ofast -Wall -Wextra \
 -lavformat -lavdevice -lavcodec -lavutil -pthread -ldl -lswscale -lbz2 -lz -lm \
 -std=c++11 "./read_mp3.cpp"


but i get the following error :


/tmp/ccnZzoIh.o: In function `decode_audio_file(char const*, int, double**, int*)':
 read_mp3.cpp:(.text+0x2781): undefined reference to `av_register_all'
 read_mp3.cpp:(.text+0x2786): undefined reference to `avformat_alloc_context'
 read_mp3.cpp:(.text+0x279c): undefined reference to `avformat_open_input'
 read_mp3.cpp:(.text+0x27b7): undefined reference to `avformat_find_stream_info'
 read_mp3.cpp:(.text+0x284b): undefined reference to `avcodec_find_decoder'
 read_mp3.cpp:(.text+0x2858): undefined reference to `avcodec_open2'
 read_mp3.cpp:(.text+0x2865): undefined reference to `swr_alloc'
 read_mp3.cpp:(.text+0x2880): undefined reference to `av_opt_set_int'
 read_mp3.cpp:(.text+0x2896): undefined reference to `av_opt_set_int'
 read_mp3.cpp:(.text+0x28ae): undefined reference to `av_opt_set_int'
 read_mp3.cpp:(.text+0x28c4): undefined reference to `av_opt_set_int'
 read_mp3.cpp:(.text+0x28dc): undefined reference to `av_opt_set_int'
 
 /tmp/ccnZzoIh.o:read_mp3.cpp:(.text+0x28f0): more undefined references to `av_opt_set_int' follow
 /tmp/ccnZzoIh.o: In function `decode_audio_file(char const*, int, double**, int*)':
 read_mp3.cpp:(.text+0x2907): undefined reference to `av_opt_set_sample_fmt'
 read_mp3.cpp:(.text+0x291d): undefined reference to `av_opt_set_sample_fmt'
 read_mp3.cpp:(.text+0x2927): undefined reference to `swr_init'
 read_mp3.cpp:(.text+0x2931): undefined reference to `swr_is_initialized'
 read_mp3.cpp:(.text+0x2943): undefined reference to `av_init_packet'
 read_mp3.cpp:(.text+0x2948): undefined reference to `av_frame_alloc'
 read_mp3.cpp:(.text+0x297b): undefined reference to `av_read_frame'
 read_mp3.cpp:(.text+0x299a): undefined reference to `avcodec_decode_audio4'
 read_mp3.cpp:(.text+0x29cc): undefined reference to `av_samples_alloc'
 read_mp3.cpp:(.text+0x29e6): undefined reference to `swr_convert'
 read_mp3.cpp:(.text+0x2a36): undefined reference to `av_frame_free'
 read_mp3.cpp:(.text+0x2a40): undefined reference to `swr_free'
 read_mp3.cpp:(.text+0x2a48): undefined reference to `avcodec_close'
 read_mp3.cpp:(.text+0x2a52): undefined reference to `avformat_free_context'

 collect2: error: ld returned 1 exit status


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Revert "lavfi/avfiltergraph : add check before free the format"
7 août 2020, par Andreas RheinhardtRevert "lavfi/avfiltergraph : add check before free the format"
This reverts commit f156f4ab2317f22bfef33c7eaead0d5d5f162903.
The checks added by said commit are nonsense because they did not help
in case ff_merge_samplerates() or ff_merge_formats() returned NULL
while freeing one of its arguments : Said freeing does not change
the local variables of can_merge_formats().Reviewed-by : Nicolas George <george@nsup.org>
Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com> -
fftools/ffmpeg : Fix leak of AVFilterInOut in case of error
23 août 2020, par Andreas Rheinhardtfftools/ffmpeg : Fix leak of AVFilterInOut in case of error
The AVFilterInOuts normally get freed in init_output_filter() when
the corresponding streams get created ; yet if an error happens before
one reaches said point, they leak. Therefore this commit makes
ffmpeg_cleanup free them, too.Fixes ticket #8267.
Reviewed-by : Nicolas George <george@nsup.org>
Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
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