Sur d’autres sites (14217)

• FFMPEG Drag and Drop sh file

  29 avril 2021, par WFCDefi

  On Windows I have a simple batch file which I drop video files onto to convert to webms, it saves a lot of time as I prefer to just use the same configuration and don't care much about the names.

  


  @echo off 
echo. 
ffmpeg -i %1 -c:v libvpx-vp9 -quality good -cpu-used 2 -b:v 5000k -qmin 15 -qmax 45 -maxrate 500k -bufsize 1500k -framerate 60 -threads 8 -vf scale=-1:1080 -c:a libvorbis -b:a 192k -f webm %1.webm 
pause


  


  I know the .bat file won't really work in Linux (I'm on pop os so pretty much Ubuntu) so with the other lines removed and the %1 changed to $1 it works. It won't do anything if I try dragging and dropping a video file onto it though.

  


  I can type sudo then drag and drop the .sh file followed by a video into a terminal and press enter and it will have the same effect as dragging a video file onto a bat file in Windows.

  


  Is there a way to recreate dragging and dropping a file directly onto another and it executing in Linux or is the terminal the only way ?

  


• FFmpeg library is detecting pixel format of VP9 video stream not correctly

  6 avril 2023, par Pikachu

  I am using a C code to detect pixel format of VP9 video stream in a WebM container. FFmpeg version 6.0, full shared library build, downloaded from official website. Operating system is Windows 10. I feed the library with a VP9 video encoded with alpha channel, pixel format is YUVA420p. It detects pixel format as YUV420p.

  


  I have found a similar question on StackOverflow.com, Is there a way to force FFMPEG to decode a video stream with alpha from ​a WebM video encoded with libvpx-vp9 ?, but it does not actually help.

  


  When I override the decoder with a libvpx, it continues to detect the pixel format as YUV420p instead of YUVA420p.

  


  C code is following. Note that error handling in code is omitted here for StackOverflow question to be shorter.

  


  AVFormatContext *fmt_ctx = NULL;
int err = avformat_open_input(&fmt_ctx, infp, NULL, NULL);
err = avformat_find_stream_info(fmt_ctx, NULL);
int stream = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
AVCodecParameters *codecpar = fmt_ctx->streams[stream]->codecpar;

const AVCodec *codec = NULL;
if (codecpar->codec_id == AV_CODEC_ID_VP9) {
    codec = avcodec_find_decoder_by_name(CODEC_LIBVPX_VP9);
} else {
    codec = avcodec_find_decoder(codecpar->codec_id);
}

AVCodecContext *ctx = avcodec_alloc_context3(codec);
err = avcodec_parameters_to_context(ctx, codecpar);
av_log(NULL, AV_LOG_DEBUG, "Pixel format: %d.\n", ctx->pix_fmt); //TODO:DEBUG.
err = avcodec_open2(ctx, codec, NULL);


  


  The program tells Pixel format: 0., which means AV_PIX_FMT_YUV420P, not the AV_PIX_FMT_YUVA420P !

  


  If I override pixel format manually, I am able to decode video with alpha channel and to see the transparent background, but it breaks the logics, because when a real YUV420p pixel format comes in and gets overridden by YUVA420p, this will be a problem.

  


  if (codecpar->codec_id == AV_CODEC_ID_VP9) {
    if (strcmp(codec->name, CODEC_LIBVPX_VP9) == 0) {
        if (ctx->pix_fmt == AV_PIX_FMT_YUV420P) {
            ctx->pix_fmt = AV_PIX_FMT_YUVA420P;
        }
    }
}


  


  At the same time ffmpeg tool started from command line with libvpx decoder tells that my video has YUVA420p pixel format. Output is following.

  


  D:\Temp\4>ffmpeg -c:v libvpx-vp9 -i yuva.webm
ffmpeg version 6.0-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-shared --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58.  2.100 / 58.  2.100
  libavcodec     60.  3.100 / 60.  3.100
  libavformat    60.  3.100 / 60.  3.100
  libavdevice    60.  1.100 / 60.  1.100
  libavfilter     9.  3.100 /  9.  3.100
  libswscale      7.  1.100 /  7.  1.100
  libswresample   4. 10.100 /  4. 10.100
  libpostproc    57.  1.100 / 57.  1.100
[libvpx-vp9 @ 000001ecdf6002c0] v1.13.0-71-g45dc0d34d
    Last message repeated 1 times
Input #0, matroska,webm, from 'yuva.webm':
  Metadata:
    ENCODER         : Lavf60.3.100
  Duration: 00:00:05.55, start: 0.000000, bitrate: 227 kb/s
  Stream #0:0: Video: vp9 (Profile 0), yuva420p(tv, progressive), 1920x1080, SAR 1:1 DAR 16:9, 60 fps, 60 tbr, 1k tbn
    Metadata:
      alpha_mode      : 1
      ENCODER         : Lavc60.3.100 libvpx-vp9
      DURATION        : 00:00:05.550000000
At least one output file must be specified


  


  Here is my YUVA420p in the first video stream at the end of the console output :

  


  Stream #0:0: Video: vp9 (Profile 0), yuva420p(tv, progressive), 1920x1080, SAR 1:1 DAR 16:9, 60 fps, 60 tbr, 1k tbn


  


  


  The questions are following.

  


  

  1. How to detect real pixel format of VP9 video with FFmpeg library in C code reliably ?

  


  2. Why is the C code not detecting the actual pixel format even with codec overriden to libvpx ?

  


  


  Thank you.

  


• Unable to port FFmpeg C library into android

  13 décembre 2017, par Navjot Bedi

  What I exactly want to-do : Access the ffmpeg.c file to modify the int main(int argc, char **argv) function to JNI and passing the command of ffmpeg as string.

  I have tried to port ffmpeg C library to android(ARM processor). I followed following different ways to do this.

  1st Try : using official ffmpeg installation documentation. Steps as follows

  a) git clone git ://source.ffmpeg.org/ffmpeg.git ffmpeg

  b) Read the INSTALL file.

  c) Download x264 library and build by using build_x264.sh which build successfully.

      NDK=/home/nav/Work/android/ndk
  
      PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt
  
      PLATFORM=$NDK/platforms/android-8/arch-arm
  
      PREFIX=/home/nav/28ffmpeg/android-ffmpeg                
  
      ./configure --prefix=$PREFIX --enable-static --enable-pic --disable-asm --disable-cli --host=arm-linux --cross-prefix=$PREBUILT/linux-x86/bin/arm-linux-androideabi- --sysroot=$PLATFORM
  
    make
  
    sudo make install
  
    sudo ldconfig

  d) Then I download ffmpeg library from (http://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2) build it by using build_android.sh

  #!/bin/bash
  
  
  
  NDK=/home/nav/Work/android/ndk
  
  PLATFORM=$NDK/platforms/android-8/arch-arm
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
  
  PREFIX=/home/nav/28ffmpeg/android-ffmpeg
  
  
  
  function build_one
  
                  {
  
                  ./configure --target-os=linux --prefix=$PREFIX \
  
                  --enable-cross-compile \
  
                  --enable-runtime-cpudetect \
  
                  --disable-asm \
  
                  --arch=arm \
  
                  --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
  
                  --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
                  --disable-stripping \
  
                  --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
  
                  --sysroot=$PLATFORM \
  
                  --enable-nonfree \
  
                  --enable-version3 \
  
                  --disable-everything \
  
                  --enable-gpl \
  
                  --disable-doc \
  
                  --enable-avresample \
  
                  --enable-demuxer=rtsp \
  
                  --enable-muxer=rtsp \
  
                  --disable-ffplay \
  
                  --disable-ffserver \
  
                  --enable-ffmpeg \
  
                  --disable-ffprobe \
  
                  --enable-libx264 \
  
                  --enable-encoder=libx264 \
  
                  --enable-decoder=h264 \
  
                  --enable-protocol=rtp \
  
                  --enable-hwaccels \
  
                  --enable-zlib \
  
                  --disable-devices \
  
                  --disable-avdevice \
  
  --extra-cflags="-I/home/android-ffmpeg/include -fPIC -DANDROID -D__thumb__ -mthumb -Wfatal-errors -Wno-deprecated -mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=armv7-a" \
  
                  --extra-ldflags="-L/home/android-ffmpeg/lib"
  
                  make -j4 install
  
  
  
  $PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
  
  $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -L$PREFIX/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavfilter/libavfilter.a libavresample/libavresample.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog -lx264 --warn-once --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a
  
                  }
  
  
  
                  build_one

  e) Initially it works perfectly. But after that error comes :

  libavformat/libavformat.a(log2_tab.o):(.rodata+0x0): multiple definition of `ff_log2_tab'
  
  libavcodec/libavcodec.a(log2_tab.o):(.rodata+0x0): first defined here
  
  libavutil/libavutil.a(log2_tab.o):(.rodata+0x0): multiple definition of `ff_log2_tab'
  
  libavcodec/libavcodec.a(log2_tab.o):(.rodata+0x0): first defined here
  
  build_android.sh: 48: build_one: not found

  Result : libffmpeg.so not found.

  2nd Try : Then I follow steps in http://dl.dropbox.com/u/22605641/ffmpeg_android/main.html-> Builds

  a) I downloaded Pre-Build libffmpeg.so from above link.

  b) Add libffmpeg.so to libs/armeabi/ .

  c) Make Android.mk

  include $(CLEAR_VARS)
  
  LOCAL_MODULE := ffmpeg
  
  LOCAL_SRC_FILES := libffmpeg.so
  
  include $(PREBUILT_SHARED_LIBRARY)
  
  
  
  LOCAL_PATH := $(call my-dir)
  
  
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE := main
  
  LOCAL_STATIC_LIBRARIES += ffmpeg
  
  LOCAL_SRC_FILES := ffmpeg-test.c
  
  include $(BUILD_SHARED_LIBRARY)

  d) Then I do all ndk set up and all.Copy ffmpeg.c from library to ffmpeg-test.c by changing its int main function to my JNI functin and include all necessary include files.

  Error :

  Console :

    /home/nav/Work/android/ndk/ndk-build all 
  
  Prebuilt       : libffmpeg.so <= jni/
  
  Install        : libffmpeg.so => libs/armeabi/libffmpeg.so
  
  Compile thumb  : main <= ffmpeg-test.c
  
  jni/ffmpeg-test.c: In function 'print_report':
  
  jni/ffmpeg-test.c:1139:94: warning: incompatible implicit declaration of built-in function 'log2' [enabled by default]
  
  SharedLibrary  : libmain.so
  
  /home/nav/Work/android/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/main/ffmpeg-test.o: in function check_keyboard_interaction:jni/ffmpeg-test.c:2496: error: undefined reference to 'qp_hist'

  and many other undefined references.