Newest 'ffmpeg' Questions - Stack Overflow

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MobileVlcKit compiling Failed

25 février 2016, par Bittoo

Hi i am trying to use MobileVLCKit.For that i am using cocoapads like below pod 'MobileVLCKit'

pod 'MobileVLCKit'

then i compile my project it is showing plenty of errors below is my error Log

  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

"std::basic_string, std::allocator >::find(wchar_t const*, unsigned long, unsigned long) const", referenced from:
  TagLib::String::find(TagLib::String const&, int) const in MobileVLCKit(tstring.cpp.o)
  TagLib::String::split(TagLib::String const&) const in MobileVLCKit(tstring.cpp.o)

  dash::mpd::BasicCMParser::parseCommonAttributesElements(dash::xml::Node*, dash::mpd::CommonAttributesElements*, dash::mpd::CommonAttributesElements*) const in MobileVLCKit(libdash_plugin_la-BasicCMParser.o)

I tried with architecture x86_64 but still showing lot of errors. I don't know how to clear these errors.so can any body please help me

Low performance when extracting frames from video

25 février 2016, par Rakatan
I am writing a video processing application and have hit a bit of a snag.

The idea is to extract frames (images) from a video file, process them on the GPU and then write them back to a new video file.

So far i have been successful in doing this using JavaCV.

The only problem is that extracting the frames takes a very long time (in the 200ms region). This is way to much, as added to the GPU processing time and the time it takes to write to a new file, it results in a total process duration of about 700ms per frame.

This is how i grab the frames:
```
 FFmpegFrameGrabber frameGrabber = new FFmpegFrameGrabber(videoLocation);
 frameGrabber.start();

 frameGrabber.setFrameNumber(frameNumber);
 frame = frameGrabber.grabImage();
```
Pretty standard, nothing special, and it works. I am able to process the frame, convert it to a bitmap, etc...

As i have said before, the bottom two instructions (setting the frame number and grabbing the image) take a very very long time. Writing the frames also takes a fair bit.

I would greatly appreciate if anyone has any input regarding this issue. Maybe i'm not setting up something correctly, maybe there is another solution that is faster.

FFmpeg support for libstagefright hardware decoding

25 février 2016, par Ming Zhang

everyone: I am new to ffmpeg. Recently I am working on project to port ffmpeg to android device. At the beginning, I compiled ffmpeg to shared libs(.so files) in a very normal way following some guides on Internet, load them into my android app. It works perfectly.

Now I want ffmpeg to use libstagefright to fulfill HW decoding. The problem is, I can compile the .so libs, but when I launch my app and load those .so libs, there is always a java.lang.UnsatisfiedLinkError: Cannot load library: reloc_library[1314]: 114 cannot locate '_ZN7android11MediaBufferC1Ej'

I stuck there for a few days. Does anyone encountered any similar problems before? It would be great if someone can give me some hint about this error.

My steps: 1. Compile ffmpeg-2.1.4 souce code to .so shared libs. I use the build_libstagefright script to do this, and make some modification based on some guides from Internet.

#!/bin/bash
#export NDK=/home/mingzhang/android/android-ndk-r9c
export NDK=/home/mingzhang/android/android-ndk-r7
if [ "$NDK" = "" ]; then
    echo NDK variable not set, assuming ${HOME}/android-ndk
    export NDK=${HOME}/android-ndk
fi

echo "Fetching Android system headers"
git clone --depth=1 --branch gingerbread-release git://github.com/CyanogenMod/android_frameworks_base.git ../android-source/frameworks/base
git clone --depth=1 --branch gingerbread-release git://github.com/CyanogenMod/android_frameworks_av.git ../android-source/frameworks/av
git clone --depth=1 --branch gingerbread-release git://github.com/CyanogenMod/android_frameworks_native.git ../android-source/frameworks/native
git clone --depth=1 --branch gingerbread-release git://github.com/CyanogenMod/android_hardware_libhardware.git ../android-source/hardware/libhardware
git clone --depth=1 --branch gingerbread-release git://github.com/CyanogenMod/android_system_core.git ../android-source/system/core

echo "Fetching Android libraries for linking"
# Libraries from any froyo/gingerbread device/emulator should work
# fine, since the symbols used should be available on most of them.
#if [ ! -d "../android-libs" ]; then
#    if [ ! -f "../update-cm-7.0.3-N1-signed.zip" ]; then
#        wget http://download.cyanogenmod.com/get/update-cm-7.0.3-N1-signed.zip -P../
#    fi
#    unzip ../update-cm-7.0.3-N1-signed.zip system/lib/* -d../
#    mv ../system/lib ../android-libs
#    rmdir ../system
#fi

SYSROOT=$NDK/platforms/android-9/arch-arm
# Expand the prebuilt/* path into the correct one
#TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64
TOOLCHAIN=/home/mingzhang/android/android-ndk-r7/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
export PATH=$TOOLCHAIN/bin:$PATH
ANDROID_SOURCE=../android-source
ANDROID_LIBS=../android-libs
ABI="armeabi-v7a"
CC=$TOOLCHAIN/bin/arm-linux-androideabi-gcc
#CC=$TOOLCHAIN/bin/arm-eabi-gcc-4.4.3
NM=$TOOLCHAIN/bin/arm-linux-androideabi-nm
#NM=$TOOLCHAIN/bin/arm-eabi-nm

rm -rf ../build/stagefright
mkdir -p ../build/stagefright

ADDI_CFLAGS="-marm"
DEST=../build/stagefright
DEST="$DEST/$ABI"

FLAGS="--target-os=linux --arch=arm --cpu=armv7-a --cross-prefix=arm-linux-androideabi- --cc=$CC --nm=$NM"
#FLAGS="--target-os=linux --arch=arm --cpu=armv7-a --cross-prefix=arm-eabi- --cc=$CC --nm=$NM"
FLAGS="$FLAGS --sysroot=$SYSROOT"
#FLAGS="$FLAGS --disable-avdevice --disable-decoder=h264 --disable-decoder=h264_vdpau --enable-libstagefright-h264"
FLAGS="$FLAGS --enable-shared --disable-demuxers --disable-muxers --disable-parsers --disable-avdevice --disable-filters --disable-programs --disable-encoders --disable-decoders --disable-decoder=h264 --disable-decoder=h264_vdpau --enable-decoder=libstagefright_h264 --enable-libstagefright-h264 \
    --enable-asm \
    --enable-neon \
    --enable-cross-compile \
    --enable-gpl \
    --disable-static \
    --enable-memalign-hack"

EXTRA_CFLAGS="-I$DEST/include"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/frameworks/native/include"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/frameworks/native/include/media/openmax"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/frameworks/av/include"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/frameworks/base/include -I$ANDROID_SOURCE/system/core/include"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/hardware/libhardware/include"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/frameworks/base/media/libstagefright"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$ANDROID_SOURCE/frameworks/base/include/media/stagefright/openmax"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$NDK/sources/cxx-stl/gnu-libstdc++/4.6/include -I$NDK/sources/cxx-stl/gnu-libstdc++/4.6/libs/$ABI/include"
EXTRA_CFLAGS="$EXTRA_CFLAGS -I$NDK/sources/cxx-stl/stlport/stlport"
EXTRA_CFLAGS="$EXTRA_CFLAGS -march=armv7-a -mfloat-abi=softfp -mfpu=neon -marm -mtune=cortex-a8"
EXTRA_CFLAGS="$EXTRA_CFLAGS -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -D_STLP_USE_NEWALLOC"

EXTRA_LDFLAGS="-Wl,--fix-cortex-a8 -L$ANDROID_LIBS -Wl,-rpath-link,$ANDROID_LIBS -L$NDK/sources/cxx-stl/gnu-libstdc++/4.6/libs/$ABI -static-libstdc++"
EXTRA_CXXFLAGS="-Wno-multichar -fno-exceptions -fno-rtti"
FLAGS="$FLAGS --prefix=$DEST"

mkdir -p $DEST

echo $FLAGS --extra-cflags="$EXTRA_CFLAGS" --extra-ldflags="$EXTRA_LDFLAGS" --extra-cxxflags="$EXTRA_CXXFLAGS" > $DEST/info.txt
./configure $FLAGS --extra-cflags="$EXTRA_CFLAGS" --extra-ldflags="$EXTRA_LDFLAGS" --extra-cxxflags="$EXTRA_CXXFLAGS" | tee $DEST/configuration.txt
[ $PIPESTATUS == 0 ] || exit 1
make clean
#make -j4 || exit 1
#make -j4
make install || exit 1

Copy the compiled include and lib directories to my android-ndk-r7/sources/ffmpeg-2.1.4/android/arm directory. The Android.mk file under this directory is.

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS) LOCAL_MODULE:= libavcodec LOCAL_SRC_FILES:= lib/libavcodec-55.so LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS) LOCAL_MODULE:= libavformat LOCAL_SRC_FILES:= lib/libavformat-55.so LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS) LOCAL_MODULE:= libswscale LOCAL_SRC_FILES:= lib/libswscale-2.so LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS) LOCAL_MODULE:= libavutil LOCAL_SRC_FILES:= lib/libavutil-52.so LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS) LOCAL_MODULE:= libavfilter LOCAL_SRC_FILES:= lib/libavfilter-3.so LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS) LOCAL_MODULE:= libwsresample LOCAL_SRC_FILES:= lib/libswresample-0.so LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include include $(PREBUILT_SHARED_LIBRARY)

Under the jni directory of my android app, the Android.mk is.

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)

LOCAL_MODULE    := libripple
#LOCAL_CFLAGS    := -Werror
LOCAL_SRC_FILES := entrypoint.cpp scene.cpp
LOCAL_LDLIBS    := -llog -lGLESv2 -lm

include $(BUILD_SHARED_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE    := myfflib
LOCAL_SRC_FILES := fflib.c
LOCAL_LDLIBS := -L/home/mingzhang/ffmpeg_android/android-libs -llog -ljnigraphics -lz -landroid -ldl -lm -llog -lgcc -lc -lstagefright -lmedia -lutils -lbinder #-lstdc++
LOCAL_SHARED_LIBRARIES := libavformat libavcodec libswscale libavutil libutils libstagefright libbinder libmedia libstdc++-6

include $(BUILD_SHARED_LIBRARY)
$(call import-module,ffmpeg-2.1.4/android/arm)

And the Application.mk is:

APP_ABI=armeabi-v7a
#APP_STL=gnustl_static
APP_STL=stlport_static

I am not sure what else materials you need, if anything is missing, please let me know, I will upload it. Thank you guys very much!!!

Preferred way to make script directly executable

25 février 2016, par David542
I can run ffmpeg by executing the executable file in ~/bin:
```
$ ~/bin/ffmpeg
```
To be able to just do $ ffmpeg, one option would be to create an alias in my '~.bash_profile or $ sudo ln -s ~/bin/ffmpeg /usr/bin/ffmpeg. Is there a better way to do this, so that I can use ffmpeg in scripts and that command will be recognized?
ffmpeg - How is avcodec_decode_video2 works ?

25 février 2016, par Bryce
As we know, one AVPacket contains one AVFrame, and we can use int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame, int *got_frame_ptr, const AVPacket *avpkt) to decode a packet to frame, if it works, got_frame_ptr will set with nonzero, otherwise, it's zero.
```
int len = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
if ( len < 0 )
{
    fprintf(stderr, "Problems decoding frame\n");
    return 1;
}

fprintf(stderr, "len = %d\n", len );

// Did we get a video frame?
if(frameFinished) {
    dosomething();
}
```
I wanna konw how it would fail(got_frame_ptr is 0), is the AVPacket we got error or something else?

1 | ... | 6980 | 6981 | 6982 | 6983 | 6984 | 6985 | 6986 | 6987 | 6988 | ... | 9489

Newest 'ffmpeg' Questions - Stack Overflow

Les articles publiés sur le site

MobileVlcKit compiling Failed

Low performance when extracting frames from video

FFmpeg support for libstagefright hardware decoding

Preferred way to make script directly executable

ffmpeg - How is avcodec_decode_video2 works ?

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