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• Decoding a h264 (High) stream with OpenCV's ffmpeg on Ubuntu

  9 janvier 2017, par arvids

  I am working with a video stream (no audio) from an ip camera on Ubuntu 14.04. Also i am a beginner with Ubuntu and everything on it. Everything was going great with a camera that has these parameters (from FFMPEG) :

  Input #0, rtsp, from 'rtsp://*private*:8900/live.sdp': 0B f=0/0   
  
    Metadata:
  
      title           : RTSP server
  
      Stream #0:0: Video: h264 (Main), yuv420p(progressive), 352x192, 29.97 tbr, 90k tbn, 180k tbc

  But then i changed to a newer camera, which has these parameters :

  Input #0, rtsp, from 'rtsp://*private*/media/video2':0B f=0/0   
  
    Metadata:
  
      title           : VCP IPC Realtime stream
  
      Stream #0:0: Video: h264 (High), yuvj420p(pc, bt709, progressive), 1280x720, 25 fps, 25 tbr, 90k tbn, 50 tbc

  My C++ program uses OpenCV3 to process the stream. By default OpenCV uses ffmpeg to decode and display the stream with function VideoCapture.

  VideoCapture vc;
  
  vc.open(input_stream);
  
  while ((vc >> frame), !frame.empty()) {
  
     *do work*
  
  }

  With the new camera stream i get errors like these (from ffmpeg) :

  [h264 @ 0x7c6980] cabac decode of qscale diff failed at 41 38
  
  [h264 @ 0x7c6980] error while decoding MB 41 38, bytestream (3572)
  
  [h264 @ 0x7c6980] left block unavailable for requested intra mode at 0 44
  
  [h264 @ 0x7c6980] error while decoding MB 0 44, bytestream (4933)
  
  [h264 @ 0x7bc2c0] SEI type 25 truncated at 208
  
  [h264 @ 0x7bfaa0] SEI type 25 truncated at 206
  
  [h264 @ 0x7c6980] left block unavailable for requested intra mode at 0 18
  
  [h264 @ 0x7c6980] error while decoding MB 0 18, bytestream (14717)

  The image sometimes is glitched, sometimes completely frozen. After a few seconds to a few minutes the stream freezes completely without an error. However on vlc it plays perfectly. I installed the newest version (3.2.2) of ffmpeg player with

  ./configure --enable-gpl --enable-libx264

  Now playing directly with ffplay (instead of launching from source code with OpenCV function VideoCapture), the stream plays better, doesn’t freeze, but sometimes still displays warnings :

  [NULL @ 0x7f834c008c00] SEI type 25 size 896 truncated at 320=1/1   
  
  [h264 @ 0x7f834c0d5d20] SEI type 25 size 896 truncated at 319=1/1   
  
  [rtsp @ 0x7f834c0008c0] max delay reached. need to consume packet   
  
  [rtsp @ 0x7f834c0008c0] RTP: missed 1 packets
  
  [h264 @ 0x7f834c094740] concealing 675 DC, 675 AC, 675 MV errors in P frame
  
  [NULL @ 0x7f834c008c00] SEI type 25 size 896 truncated at 320=1/1  

  Changing the camera hardware is not an option. The camera can be set to encode to h265 or mjpeg. When encoding to mjpeg it can output 5 fps, which is not enough. Decoding to a static video is not an option either, because i need to display real time results about the stream. Here is a list of API backends that can be used in function VideoCapture. Maybe i should swithc to some other decoder and player ?
  From my research i conclude that i have these options :

  • Somehow get OpenCV to use the ffmpeg player from another directory, where it is compiled with libx264

  • Somehow get OpenCV to use libVlc instead of ffmpeg

  One example of switching to vlc is here, but i don’t understand it well enough to say if that is what i need. Or maybe i should be parsing the stream in code ? I don’t rule out that this could be some basic problem due to a lack of dependencies, because, as i said, i’m a beginner with Ubuntu.

  • Use vlc to preprocess the stream, as suggested here.

  This is probably slow, which again is bad for real time results.
  Any suggestions and coments will be appreciated.

• Linking shared libraries (.so) in Android Studio 2.2.2

  22 novembre 2016, par fadi

  I am really stuck and desperate for an answer.
  I have looked pretty much everywhere online to solve this problem with no real success.

  Basically I have compiled ffmpeg for android and I am trying to use the (.so) files inside Android Studio 2.2.2.

  The problem is that I keep getting this error when I try to compile my code
  Please note that my code worked perfectly under MS Visual Studio and I am certain it works as it should.

  Compile ERROR Message

  I am thinking this error means that I am not linking my shared libraries (.so) files against my .cpp file (correct me if I am wrong).

  Things I tried :

  • I have tried including my .so files inside main/jniLibs, and still didn’t work.

  • I put the .so files inside app/libs, and still no success.

  • Provided linking rules in cmake for example :

    add_library(B SHARED IMPORTED)
    
    set_target_properties(B PROPERTIES
    
         IMPORTED_LOCATION src/main/jniLibs/armeabi-v7a/libavformat-55.so
    
    )
    
    include_directories(src/main/cpp/include/)
    
    target_link_libraries(native-lib B)

    This gave me another error which looks like this :

    Error:error: 'src/main/jniLibs/armeabi-v7a/libavformat-55.so', needed by '../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so', missing and no known rule to make it

  Here is the structure of my project tree :

  Project structure

  I really need help.

• Building FFMPEG on UBUNTU facing issue while compiling common.mak file

  9 juin 2016, par sumit singh

  I am compiling the ffmpeg library i am facing some issues while compiling this.

  I follow the steps of compilation form here.But i am failed to compile.
  The issues are as below.

  WARNING: /home/sumit/android-ndk-r10e/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-androideabi-pkg-config not found, library detection may fail.
  
  libavcodec/bsf_list.c is unchanged
  
  libavformat/protocol_list.c is unchanged
  
  common.mak:26: *** unterminated call to function `foreach': missing `)'.  Stop.
  
  common.mak:26: *** unterminated call to function `foreach': missing `)'.  Stop.
  
  common.mak:26: *** unterminated call to function `foreach': missing `)'.  Stop.
  
  sumit@sumit-H81M-S:~/android-ndk-r10e/sources/ffmpeg$ 

  here is my build_android.sh file-

  #!/bin/bash
  
  
  
  NDK=$HOME/android-ndk-r10e
  
  
  
  SYSROOT=$NDK/platforms/android-19/arch-arm/
  
  
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86
  
  
  
  function build_one
  
  
  
  {
  
  ./configure --prefix=$PREFIX --enable-shared --disable-static --disable-doc --disable-ffmpeg --disable-ffplay --disable-ffprobe --disable-ffserver --disable-avdevice --disable-doc --disable-symver --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- --target-os=linux --arch=arm --enable-cross-compile --sysroot=$SYSROOT --extra-cflags="-Os -fpic $ADDI_CFLAGS" --extra-ldflags="$ADDI_LDFLAGS" 
  
  $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  
  make
  
  make install
  
  }
  
  
  
  CPU=arm
  
  
  
  PREFIX=$(pwd)/android/$CPU 
  
  
  
  ADDI_CFLAGS="-marm"
  
  
  
  build_one

  common.mak-

  #
  
  # common bits used by all libraries
  
  #
  
  
  
  # first so "all" becomes default target
  
  all: all-yes
  
  
  
  DEFAULT_YASMD=.dbg
  
  
  
  ifeq ($(DBG),1)
  
  YASMD=$(DEFAULT_YASMD)
  
  else
  
  YASMD=
  
  endif
  
  
  
  ifndef SUBDIR
  
  
  
  ifndef V
  
  Q      = @
  
  ECHO   = printf "$(1)\t%s\n" $(2)
  
  BRIEF  = CC CXX OBJCC HOSTCC HOSTLD AS YASM AR LD STRIP CP WINDRES
  
  SILENT = DEPCC DEPHOSTCC DEPAS DEPYASM RANLIB RM
  
  
  
  MSG    = $@
  
  M      = @$(call ECHO,$(TAG),$@);
  
  $(foreach VAR,$(BRIEF), \
  
      $(eval override $(VAR) = @$$(call ECHO,$(VAR),$$(MSG)); $($(VAR))))
  
  $(foreach VAR,$(SILENT),$(eval override $(VAR) = @$($(VAR))))
  
  $(eval INSTALL = @$(call ECHO,INSTALL,$$(^:$(SRC_DIR)/%=%)); $(INSTALL))
  
  endif
  
  
  
  ALLFFLIBS = avcodec avdevice avfilter avformat avresample avutil postproc swscale swresample
  
  
  
  # NASM requires -I path terminated with /
  
  IFLAGS     := -I. -I$(SRC_LINK)/
  
  CPPFLAGS   := $(IFLAGS) $(CPPFLAGS)
  
  CFLAGS     += $(ECFLAGS)
  
  CCFLAGS     = $(CPPFLAGS) $(CFLAGS)
  
  OBJCFLAGS  += $(EOBJCFLAGS)
  
  OBJCCFLAGS  = $(CPPFLAGS) $(CFLAGS) $(OBJCFLAGS)
  
  ASFLAGS    := $(CPPFLAGS) $(ASFLAGS)
  
  CXXFLAGS   += $(CPPFLAGS) $(CFLAGS)
  
  YASMFLAGS  += $(IFLAGS:%=%/) -Pconfig.asm
  
  
  
  HOSTCCFLAGS = $(IFLAGS) $(HOSTCPPFLAGS) $(HOSTCFLAGS)
  
  LDFLAGS    := $(ALLFFLIBS:%=$(LD_PATH)lib%) $(LDFLAGS)
  
  
  
  define COMPILE
  
         $(call $(1)DEP,$(1))
  
         $($(1)) $($(1)FLAGS) $($(1)_DEPFLAGS) $($(1)_C) $($(1)_O) $(patsubst $(SRC_PATH)/%,$(SRC_LINK)/%,$<)
  
  endef
  
  
  
  COMPILE_C = $(call COMPILE,CC)
  
  COMPILE_CXX = $(call COMPILE,CXX)
  
  COMPILE_S = $(call COMPILE,AS)
  
  COMPILE_M = $(call COMPILE,OBJCC)
  
  COMPILE_HOSTC = $(call COMPILE,HOSTCC)
  
  
  
  %.o: %.c
  
      $(COMPILE_C)
  
  
  
  %.o: %.cpp
  
      $(COMPILE_CXX)
  
  
  
  %.o: %.m
  
      $(COMPILE_M)
  
  
  
  %.s: %.c
  
      $(CC) $(CCFLAGS) -S -o $@ $<
  
  
  
  %.o: %.S
  
      $(COMPILE_S)
  
  
  
  %_host.o: %.c
  
      $(COMPILE_HOSTC)
  
  
  
  %.o: %.rc
  
      $(WINDRES) $(IFLAGS) --preprocessor "$(DEPWINDRES) -E -xc-header -DRC_INVOKED $(CC_DEPFLAGS)" -o $@ $<
  
  
  
  %.i: %.c
  
      $(CC) $(CCFLAGS) $(CC_E) $<
  
  
  
  %.h.c:
  
      $(Q)echo '#include "$*.h"' >$@
  
  
  
  %.ver: %.v
  
      $(Q)sed 's/$$MAJOR/$($(basename $(@F))_VERSION_MAJOR)/' $^ | sed -e 's/:/:\
  
  /' -e 's/; /;\
  
  /g' > $@
  
  
  
  %.c %.h: TAG = GEN
  
  
  
  # Dummy rule to stop make trying to rebuild removed or renamed headers
  
  %.h:
  
      @:
  
  
  
  # Disable suffix rules.  Most of the builtin rules are suffix rules,
  
  # so this saves some time on slow systems.
  
  .SUFFIXES:
  
  
  
  # Do not delete intermediate files from chains of implicit rules
  
  $(OBJS):
  
  endif
  
  
  
  include $(SRC_PATH)/arch.mak
  
  
  
  OBJS      += $(OBJS-yes)
  
  SLIBOBJS  += $(SLIBOBJS-yes)
  
  FFLIBS    := $($(NAME)_FFLIBS) $(FFLIBS-yes) $(FFLIBS)
  
  TESTPROGS += $(TESTPROGS-yes)
  
  
  
  LDLIBS       = $(FFLIBS:%=%$(BUILDSUF))
  
  FFEXTRALIBS := $(LDLIBS:%=$(LD_LIB)) $(EXTRALIBS)
  
  
  
  OBJS      := $(sort $(OBJS:%=$(SUBDIR)%))
  
  SLIBOBJS  := $(sort $(SLIBOBJS:%=$(SUBDIR)%))
  
  TESTOBJS  := $(TESTOBJS:%=$(SUBDIR)%) $(TESTPROGS:%=$(SUBDIR)%-test.o)
  
  TESTPROGS := $(TESTPROGS:%=$(SUBDIR)%-test$(EXESUF))
  
  HOSTOBJS  := $(HOSTPROGS:%=$(SUBDIR)%.o)
  
  HOSTPROGS := $(HOSTPROGS:%=$(SUBDIR)%$(HOSTEXESUF))
  
  TOOLS     += $(TOOLS-yes)
  
  TOOLOBJS  := $(TOOLS:%=tools/%.o)
  
  TOOLS     := $(TOOLS:%=tools/%$(EXESUF))
  
  HEADERS   += $(HEADERS-yes)
  
  
  
  PATH_LIBNAME = $(foreach NAME,$(1),lib$(NAME)/$($(2)LIBNAME))
  
  DEP_LIBS := $(foreach lib,$(FFLIBS),$(call PATH_LIBNAME,$(lib),$(CONFIG_SHARED:yes=S)))
  
  STATIC_DEP_LIBS := $(foreach lib,$(FFLIBS),$(call PATH_LIBNAME,$(lib)))
  
  
  
  SRC_DIR    := $(SRC_PATH)/lib$(NAME)
  
  ALLHEADERS := $(subst $(SRC_DIR)/,$(SUBDIR),$(wildcard $(SRC_DIR)/*.h $(SRC_DIR)/$(ARCH)/*.h))
  
  SKIPHEADERS += $(ARCH_HEADERS:%=$(ARCH)/%) $(SKIPHEADERS-)
  
  SKIPHEADERS := $(SKIPHEADERS:%=$(SUBDIR)%)
  
  HOBJS        = $(filter-out $(SKIPHEADERS:.h=.h.o),$(ALLHEADERS:.h=.h.o))
  
  checkheaders: $(HOBJS)
  
  .SECONDARY:   $(HOBJS:.o=.c)
  
  
  
  alltools: $(TOOLS)
  
  
  
  $(HOSTOBJS): %.o: %.c
  
      $(COMPILE_HOSTC)
  
  
  
  $(HOSTPROGS): %$(HOSTEXESUF): %.o
  
      $(HOSTLD) $(HOSTLDFLAGS) $(HOSTLD_O) $^ $(HOSTLIBS)
  
  
  
  $(OBJS):     | $(sort $(dir $(OBJS)))
  
  $(HOBJS):    | $(sort $(dir $(HOBJS)))
  
  $(HOSTOBJS): | $(sort $(dir $(HOSTOBJS)))
  
  $(SLIBOBJS): | $(sort $(dir $(SLIBOBJS)))
  
  $(TESTOBJS): | $(sort $(dir $(TESTOBJS)))
  
  $(TOOLOBJS): | tools
  
  
  
  OBJDIRS := $(OBJDIRS) $(dir $(OBJS) $(HOBJS) $(HOSTOBJS) $(SLIBOBJS) $(TESTOBJS))
  
  
  
  CLEANSUFFIXES     = *.d *.o *~ *.h.c *.map *.ver *.ver-sol2 *.ho *.gcno *.gcda *$(DEFAULT_YASMD).asm
  
  DISTCLEANSUFFIXES = *.pc
  
  LIBSUFFIXES       = *.a *.lib *.so *.so.* *.dylib *.dll *.def *.dll.a
  
  
  
  define RULES
  
  clean::
  
      $(RM) $(HOSTPROGS)
  
      $(RM) $(TOOLS)
  
  endef
  
  
  
  $(eval $(RULES))
  
  
  
  -include $(wildcard $(OBJS:.o=.d) $(HOSTOBJS:.o=.d) $(TESTOBJS:.o=.d) $(HOBJS:.o=.d) $(SLIBOBJS:.o=.d)) $(OBJS:.o=$(DEFAULT_YASMD).d)