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  • errors when compiling c code with ffmpeg library

    2 juin 2017, par Kindermann

    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

    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

    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 :

    EDIT :

    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)

    EDIT :

    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'

    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’

  • errors when compiling c code with ffmpeg library

    2 mai 2017, par Kindermann

    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

    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

    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 :

    EDIT :

    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)

    EDIT :

    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'

    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’

  • How to benchmark the decoding of the frame by ffmpeg ?

    13 juin 2018, par Anny G

    [ What I have done ]

    I am trying to measure a performance of different ffmpeg decoders by

    • timing how long the call to function avcodec_decode_video2(..) takes in ffmpeg.c and running ffmpeg binary the following way

    ~/bin/ffmpeg -benchmark_all -loglevel debug -threads 0 -i ~/Documents/video-input.h264 -c:v libx265 -x265-params crf=25 video-output.hevc

    • and by timing how long the same function takes in ffplay.c and running the ffplay binary the following way

    ~/bin/ffplay ~/Documents/video-input.h264

    In my understanding the average time for the call to that function should be the same whether I am converting the video or playing it, because I am only measuring how long it takes to decode the frame for that video. Is this a wrong way of doing it ? Please let me know if I am incorrect. The results I am getting are strange to me - the call to the aforementioned function takes twice as much in ffmpeg binary compared to ffplay binary. I have tried to run ffmpeg binary with -threads 0 and without it, but the results are still the same(twice as long as ffplay). Could it be because ffplay binary simply utilizes more threads ? When I try it with -threads 1, ffmpeg takes about 10 times as long as ffplay (which makes sense to me since before it was using several threads and now it is only using 1)

    Before I ask my question, I want you to know that I am a beginner in video processing and video encoding/decoding processes.

    [My question]

    I am wondering what would be an accurate way to measure how long it takes to decode a frame (using 1 thread) ? Should I simply measure only how long it takes to call avcodec_decode_video2(..) function using the ffmpeg binary, and not the ffplay binary ? Would the results be more accurate that way ?
    I also tried to enable -benchmark_all -loglevel debug options, but it seems like the following message bench:    64537 decode_video 0.0 is not very helpful if 0.0 is supposed to mean time. (Not sure what the other number means).

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