使用ffmpeg库编译c代码时出错
我在我的新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，我得到以下奇怪的错误：
/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 我使用以下配置多次重新安装ffmpeg库：
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，我总是遇到与上面提到的相同的错误。 我不知道…这是我使用的makefile：
编辑：
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 $(TARGET)
编辑：
在第30行将$（LIBS）和$（LDLIBS）交换为$（LDLIBS）$（LIBS）后，它看起来好多了，但编译器仍然报告以下错误：
/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'
我不知道哪个库仍然缺失？ 好像libva仍然缺失了？…我自己得到了答案……看看这里： ‘vaGetDisplay’和’vaGetDisplayDRM’的错误
您需要链接提供这些function的库以及FFmpeg。
您需要添加的链接器标志（带有各自的错误）：
-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。
编辑：OP添加了makefile
您还可以将pkg-config用于所有库。
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)