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• Encoding RGB frames using x264 and AVCodec in C

  6 novembre 2016, par deepwork

  I have RGB24 frames streamed from camera and i want to encode them into h264 ,i found that AVCodec and x264 can do so, the problem is x264 as default accepts YUV420 as input so what i wrote was a program which convert RGB frames to YUV420 .that was by sws_scale function .this works well except that it does not satisfy the required FPS because the converting (RGB->YUV420) takes time.

  This is how i setup my encoder context :

  videoStream->id = 0;
  
  vCodecCtx = videoStream->codec;
  
  
  
  vCodecCtx->coder_type       = AVMEDIA_TYPE_VIDEO;
  
  vCodecCtx->codec_id         = AV_CODEC_ID_H264;
  
  vCodecCtx->bit_rate         = 400000;
  
  vCodecCtx->width            = Width;
  
  vCodecCtx->height           = Height;
  
  vCodecCtx->time_base.den    = FPS;
  
  vCodecCtx->time_base.num    = 1;
  
  //vCodecCtx->time_base      = (AVRational){1,};
  
  vCodecCtx->gop_size         = 12;
  
  vCodecCtx->max_b_frames     = 1;
  
  vCodecCtx->pix_fmt          = AV_PIX_FMT_YUV420P;
  
  
  
  if(formatCtx->oformat->flags & AVFMT_GLOBALHEADER)
  
      vCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
  av_opt_set(vCodecCtx->priv_data, "preset", "ultrafast", 0);
  
  av_opt_set(vCodecCtx->priv_data, "profile", "baseline", AV_OPT_SEARCH_CHILDREN);
  
  
  
  if (avcodec_open2(vCodecCtx, h264Codec, NULL) < 0){
  
      return 0;
  
  }

  when i changes AV_PIX_FMT_YUV420P to AV_PIX_FMT_RGB24 ,avcodec_open2 will fail.
  i read that there is a version of libx264 for RGB called libx264rgb but i even dont know whether i have to rebuild x264 with enabling this option or to download another source or i have to do it programmatically with the first x264 lib.

  the question is how to enable RGB as input to libx264 to use with libavcodec in C .or how to make the encoding or sws_scale more fast .

  Edit :

  How i built ffmpeg :

  NDK=D:/AndroidDev/android-ndk-r9
  
  PLATFORM=$NDK/platforms/android-18/arch-arm/
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  
  
  GENERAL="\
  
  --enable-small \
  
  --enable-cross-compile \
  
  --extra-libs="-lgcc" \
  
  --arch=arm \
  
  --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
  
  --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
  --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
  
  --extra-cflags="-I../x264/android/arm/include" \
  
  --extra-ldflags="-L../x264/android/arm/lib" "
  
  
  
  
  
  MODULES="\
  
  --enable-gpl \
  
  --enable-libx264"
  
  
  
  function build_ARMv6
  
  {
  
    ./configure \
  
    --target-os=linux \
  
    --prefix=./android/armeabi \
  
    ${GENERAL} \
  
    --sysroot=$PLATFORM \
  
    --enable-shared \
  
    --disable-static \
  
    --extra-cflags=" -O3 -fpic -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 -mfloat-abi=softfp -mfpu=vfp -marm -march=armv6" \
  
    --extra-ldflags="-lx264 -Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \
  
    --enable-zlib \
  
    ${MODULES} \
  
    --disable-doc \
  
    --enable-neon
  
  
  
    make clean
  
    make
  
    make install
  
  }
  
  
  
  build_ARMv6
  
  
  
  echo Android ARMEABI builds finished

  How i built x264 :

  NDK=D:/AndroidDev/android-ndk-r9
  
  PLATFORM=$NDK/platforms/android-18/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64
  
  PREFIX=./android/arm
  
  
  
  function build_one
  
  {
  
    ./configure \
  
    --prefix=$PREFIX \
  
    --enable-static \
  
    --enable-pic \
  
    --host=arm-linux \
  
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
    --sysroot=$PLATFORM
  
  
  
    make clean
  
    make
  
    make install
  
  }
  
  
  
  build_one
  
  
  
  echo Android ARM builds finished

• ffmpeg - preserve metadata for the converted files (mtime)

  5 mars 2017, par silent

  I have a simple batch file that converts videos from mobile. I want to keep the original creation and modification time in converted files as well.

  For example, I have :

  
  
  
  name
  creation time
  modification time
  
  file.mp4
  21 March 2016
  21 March 2016
  
  

  after conversion I have :

  
  
  
  name
  creation time
  modification time
  
  file_new.mp4
  05 March 2017
  05 March 2017
  
  

  but all I want is :

  
  
  
  name
  creation time
  modification time
  
  file_new.mp4
  21 March 2016
  21 March 2016
  
  

  My ffmpeg command (Windows) :

  for %%a in ("*.mp4") do ffmpeg -i "%%a" -c:v libx264 -crf 23 -preset medium -map_metadata 0 -movflags +faststart -c:a libvo_aacenc -b:a 96k "newfiles\%%~na.mp4"

• Merge commit ’5cc0057f4910c8c72421b812c8f337ef6c43696c’

  23 mars 2017, par Clément Bœsch

  Merge commit ’5cc0057f4910c8c72421b812c8f337ef6c43696c’
  * commit ’5cc0057f4910c8c72421b812c8f337ef6c43696c’ :
  
    lavu : remove the custom atomic API
  This commit is a noop. The removal is postponed until all usages in
  
  FFmpeg are dropped as well. A patchset is on discussion on the
  
  mailing-list :
  
  http://ffmpeg.org/pipermail/ffmpeg-devel/2017-March/209003.html
  Merged-by : Clément Bœsch <u@pkh.me>
  

  • [DH] doc/libav-merge.txt