Reputation: 193
I am trying to build the example code in FFMPEG library I add the libavcode.h , libavcode.a in my project and I set the header search usr/local/include and the library search to usr/local/lib
when I compile the example I got this errors ... ( all of them related to avcodec library)
{
Undefined symbols:
"avcodec_find_encoder(CodecID)", referenced from:
video_encode_example(char const*, CodecID)in main.o
"avcodec_open2(AVCodecContext*, AVCodec*, AVDictionary**)", referenced from:
video_encode_example(char const*, CodecID)in main.o
video_decode_example(char const*, char const*)in main.o
"av_init_packet(AVPacket*)", referenced from:
video_decode_example(char const*, char const*)in main.o
"av_free(void*)", referenced from:
video_encode_example(char const*, CodecID)in main.o
video_encode_example(char const*, CodecID)in main.o
video_encode_example(char const*, CodecID)in main.o
video_decode_example(char const*, char const*)in main.o
video_decode_example(char const*, char const*)in main.o
"avcodec_alloc_context3(AVCodec*)", referenced from:
video_encode_example(char const*, CodecID)in main.o
video_decode_example(char const*, char const*)in main.o
"av_opt_set(void*, char const*, char const*, int)", referenced from:
video_encode_example(char const*, CodecID)in main.o
"av_image_alloc(unsigned char**, int*, int, int, PixelFormat, int)", referenced from:
video_encode_example(char const*, CodecID)in main.o
"avcodec_encode_video(AVCodecContext*, unsigned char*, int, AVFrame const*)", referenced from:
video_encode_example(char const*, CodecID)in main.o
video_encode_example(char const*, CodecID)in main.o
"avcodec_register_all()", referenced from:
_main in main.o
"avcodec_find_decoder(CodecID)", referenced from:
video_decode_example(char const*, char const*)in main.o
"avcodec_decode_video2(AVCodecContext*, AVFrame*, int*, AVPacket const*)", referenced from:
video_decode_example(char const*, char const*)in main.o
video_decode_example(char const*, char const*)in main.o
"avcodec_close(AVCodecContext*)", referenced from:
video_encode_example(char const*, CodecID)in main.o
video_decode_example(char const*, char const*)in main.o
"avcodec_alloc_frame()", referenced from:
video_encode_example(char const*, CodecID)in main.o
video_decode_example(char const*, char const*)in main.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
} do you know why I got this problem ?
Thanks
Upvotes: 1
Views: 1265
Reputation: 193
The solution is adding this to the header because FFMPEG written in C , I guess
extern "C"
{
#ifndef __STDC_CONSTANT_MACROS
#define __STDC_CONSTANT_MACROS
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include "avassert.h"
#include "avutil.h"
#include "intreadwrite.h"
#include "mem.h"
}
Upvotes: 2