使用 ffmpeg 库编译 c 代码时出错 [英] errors when compiling c code with ffmpeg library

问题描述

我已经在我的新 ubuntu 16.04 操作系统中安装了 ffmpeg 库.当我尝试编译我的 c 代码时，出现以下奇怪的错误:

I've installed ffmpeg library in my new ubuntu 16.04 OS. When I tried to compile my c code, I got the following strange errors:

/home/widerstand/ffmpeg_build/lib/libavutil.a(hwcontext_vaapi.o): In function `vaapi_device_free':
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:861: undefined reference to `XCloseDisplay'
/home/widerstand/ffmpeg_build/lib/libavutil.a(hwcontext_vaapi.o): In function `vaapi_device_create':
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:891: undefined reference to `XOpenDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:896: undefined reference to `vaGetDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:903: undefined reference to `XDisplayName'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:893: undefined reference to `XDisplayName'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:917: undefined reference to `vaGetDisplayDRM'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:891: undefined reference to `XOpenDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:893: undefined reference to `XDisplayName'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:898: undefined reference to `XDisplayName'
/home/widerstand/ffmpeg_build/lib/libavutil.a(hwcontext_vdpau.o): In function `vdpau_device_create':
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:431: undefined reference to `XOpenDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:437: undefined reference to `XDisplayString'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:439: undefined reference to `XDefaultScreen'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:439: undefined reference to `vdp_device_create_x11'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:433: undefined reference to `XDisplayName'
/home/widerstand/ffmpeg_build/lib/libavutil.a(hwcontext_vdpau.o): In function `vdpau_device_free':
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:410: undefined reference to `XCloseDisplay'
collect2: error: ld returned 1 exit status
Makefile:30: recipe for target 'video_analysis' failed
make: *** [video_analysis] Error 1

我已经使用以下配置多次重新安装了 ffmpeg 库:

I've reinstalled ffmpeg library multiple times using the following configurations:

PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure 
  --prefix="$HOME/ffmpeg_build" 
  --pkg-config-flags="--static" 
  --extra-cflags="-I$HOME/ffmpeg_build/include" 
  --extra-ldflags="-L$HOME/ffmpeg_build/lib" 
  --bindir="$HOME/bin" 
  --enable-gpl 
  --enable-libass 
  --enable-libfdk-aac 
  --enable-libfreetype 
  --enable-libmp3lame 
  --enable-libopus 
  --enable-libtheora 
  --enable-libvorbis 
  --enable-libvpx 
  --enable-libx264 
  --enable-nonfree
PATH="$HOME/bin:$PATH" make

安装过程每次都成功.但是当我尝试编译自己的c代码时，总是遇到与上述相同的错误.我不知道...这是我使用的生成文件:

The installation process was successful each time. But when I tried to compile my own c code, I always encountered the same errors as mentioned above. I have no idea about that... Here is the makefile I used:

FFMPEG_LIBS=    libavdevice                        
                libavformat                        
                libavfilter                        
                libavcodec                         
                libswresample                      
                libswscale                         
                libavutil                          

TARGET = video_analysis
LIBS = -lX11 -lm -lvdpau -lva
CC = gcc
CFLAGS += -O2 -g -O0
CFLAGS := $(shell pkg-config --cflags $(FFMPEG_LIBS)) $(CFLAGS)
LDLIBS := $(shell pkg-config --libs $(FFMPEG_LIBS)) $(LDLIBS)

.PHONY: default all clean

default: $(TARGET)
all: default

OBJECTS = $(patsubst %.c, %.o, $(wildcard *.c))
HEADERS = $(wildcard *.h)

%.o: %.c $(HEADERS)
    $(CC) $(CFLAGS) -c $< -o $@

.PRECIOUS: $(TARGET) $(OBJECTS)

$(TARGET): $(OBJECTS)
    $(CC) $(OBJECTS) $(LDLIBS) $(LIBS) -o $@

clean:
    -rm -f *.o
    -rm -f $(TARGET)

在第 30 行将 $(LIBS) 和 $(LDLIBS) 交换为 $(LDLIBS) $(LIBS) 后，看起来好多了，但编译器仍然报告以下错误:

Afer swapping $(LIBS) and $(LDLIBS) to be $(LDLIBS) $(LIBS) at line 30, it looks much better, but the compiler still reports the following errors:

/root/ffmpeg_build/lib/libavutil.a(hwcontext_vaapi.o): In function `vaapi_device_create':
/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:896: undefined reference to `vaGetDisplay'
/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:917: undefined reference to `vaGetDisplayDRM'

我不知道还缺少哪个库?看起来好像还缺少libva?...我自己得到了答案......看看这里:'vaGetDisplay' 和 `的错误vaGetDisplayDRM'

I have no idea which library is still missing? It looks as if libva were still missing?... I got the answer by myself...Have a look at here: errors of 'vaGetDisplay' and `vaGetDisplayDRM'

推荐答案

您需要链接提供这些功能的库以及 FFmpeg.

You need to link with the libraries which provide those functions as well as FFmpeg.

您需要添加的链接器标志是(带有各自的错误):

The linker flags you need to add are (with their respective errors):

-lvdpau - libvdpau-dev

/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:439: undefined reference to `vdp_device_create_x11'

-lva - libva-dev

/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:896: undefined reference to `vaGetDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:917: undefined reference to `vaGetDisplayDRM'

-lX11 - libx11-dev

/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:861: undefined reference to `XCloseDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:898: undefined reference to `XDisplayName'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:431: undefined reference to `XOpenDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:437: undefined reference to `XDisplayString'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vdpau.c:439: undefined reference to `XDefaultScreen'

需要在 -lav* 链接器标志之后添加这些标志.

These flags need to be added after your -lav* linker flags.

OP添加了makefile

OP added makefile

您还可以对所有库使用 pkg-config.

You can also use pkg-config for all the libraries.

FFMPEG_LIBS=    libavdevice                        
                libavformat                        
                libavfilter                        
                libavcodec                         
                libswresample                      
                libswscale                         
                libavutil

PKG_CFG_LIBS=   x11                                
                vdpau                              
                libva                              
                $(FFMPEG_LIBS)

TARGET = video_analysis
LIBS = -lm
CC = gcc
CFLAGS += -O2 -g -O0
CFLAGS := $(shell pkg-config --cflags $(PKG_CFG_LIBS)) $(CFLAGS)
LDLIBS := $(shell pkg-config --libs $(PKG_CFG_LIBS)) $(LDLIBS)

.PHONY: default all clean

default: $(TARGET)
all: default

OBJECTS = $(patsubst %.c, %.o, $(wildcard *.c))
HEADERS = $(wildcard *.h)

%.o: %.c $(HEADERS)
    $(CC) $(CFLAGS) -c $< -o $@

.PRECIOUS: $(TARGET) $(OBJECTS)

$(TARGET): $(OBJECTS)
    $(CC) $(OBJECTS) $(LIBS) $(LDLIBS) -o $@

clean:
    -rm -f *.o
    -rm -f $(TARGET)

这篇关于使用 ffmpeg 库编译 c 代码时出错的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！