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• Prevent libavformat (FFmpeg) from adding "ENCODER" tag to output / help stripping the tags

  2 mars 2014, par Wyatt8740

  I made a bash script that transfers audio or video metadata from one file to another, regardless of media container format, via FFMpeg. My problem is that FFMpeg consistently adds a 'ENCODER' tag.

  Example :

  Before running through FFMpeg :

   File : track01.cdda.flac

    Metadata:
  
      ALBUM           : Wish You Were Here
  
      ARTIST          : Pink Floyd
  
      COPYRIGHT       : 1975 Harvest Records
  
      DATE            : 1975
  
      GENRE           : Experimental Rock
  
      TITLE           : Shine On You Crazy Diamond
  
      track           : 1

  After running through FFMpeg :

   File : track01-iphone-alac.m4a

    Metadata:
  
      ALBUM=Wish You Were Here
  
      ARTIST=Pink Floyd
  
      COPYRIGHT=1975 Harvest Records
  
      DATE=1975
  
      GENRE=Experimental Rock
  
      TITLE=Shine On You Crazy Diamond
  
      track=1
  
      ENCODER=Lavf55.12.100

  So really, I want to either force FFMpeg to not add the 'ENCODER' tag, or I want to strip that tag off afterwards. Is there a way to do this ? I really don't want to spend hours trying to compile FFMpeg again on my Pentium 4 HT - the only working computer I have at the moment. I'd prefer not to have to use another program unless it's related enough to FFMpeg or MPlayer/Mencoder that I won't have to install anything new if I have those installed.

• ffmpeg libx264 neon optimization breaks execution

  27 janvier 2014, par nmxprime

  Hi use libx264 source obtained from x264-snapshot-20140122-2245 and compiling using below script

  NDK=~/Android/android-ndk-r7c
  
  PLATFORM=$NDK/platforms/android-9/arch-arm/
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
  
  function build_one
  
  {
  
  ./configure --prefix=$PREFIX \
  
  --sysroot=$PLATFORM \
  
  --disable-avs \
  
  --disable-lavf \
  
  --disable-ffms \
  
  --disable-gpac \
  
  --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
  
  --host=arm-linux \
  
  --enable-static \
  
  --libdir=$PLATFORM/usr/lib \
  
  --includedir=$PLATFORM/usr/include \
  
  --extra-cflags="-march=armv7-a -mfloat-abi=softfp -mfpu=neon -mvectorize-with-neon-quad" \
  
  --extra-ldflags="-Wl,--fix-cortex-a8" \
  
  --enable-debug

  The config log is :

  platform:      ARM
  
  system:        LINUX
  
  cli:           yes
  
  libx264:       internal
  
  shared:        no
  
  static:        yes
  
  asm:           yes
  
  interlaced:    yes
  
  avs:           no
  
  lavf:          no
  
  ffms:          no
  
  mp4:           no
  
  gpl:           yes
  
  thread:        no
  
  opencl:        yes
  
  filters:       crop select_every
  
  debug:         yes
  
  gprof:         no
  
  strip:         no
  
  PIC:           no
  
  bit depth:     8
  
  chroma format: all
  
  
  
  You can run 'make' or 'make fprofiled' now.

  I hope the above code compiles and optimizes for NEON execution

  Doubts :

  Why Threads is no, because i didn't specified --disable-thread

  What is cli and it's significance here, also significance of opencl, such that libx264 uses opencl features ?

  ---

  Then i built ffmpeg 1.2.5with following script

  ./configure --target-os=linux \
  
  --prefix=$PREFIX \
  
  --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 \
  
  --sysroot=$PLATFORM \
  
  --extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 $OPTIMIZE_CFLAGS " \
  
  --disable-shared \
  
  --enable-static \
  
  --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog -lx264 $EXTRA_LD_FLAG" \
  
  --disable-ffplay \
  
  --disable-everything \
  
  --enable-avformat \
  
  --enable-avcodec \
  
  --enable-libx264 \
  
  --enable-gpl \
  
  --enable-encoder=libx264 \
  
  --enable-encoder=libx264rgb \
  
  --enable-decoder=h264 \
  
  --disable-network \
  
  --disable-avfilter \
  
  --disable-avdevice \
  
  --enable-debug=3 \
  
  $ADDITIONAL_CONFIGURE_FLAG

  where

  ADDITIONAL_CONFIGURE_FLAG = --enable-debug=3
  
  OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mvectorize-with-neon-quad"

  The log shows NEON supported.

  When i run the code (called in a while loop),

  ret = avcodec_encode_video2(c, &pkt, picture, &got_output);//avcodec_encode_video(c, finalout, outbuf_size, picture);
  
  
  
  fprintf(stderr,"ret = %d, got-out = %d \n",ret,got_output);
  
  if (ret < 0) 
  
          fprintf(stderr, "error encoding frame\n");
  
  
  
      if (got_output) 
  
          fprintf(stderr,"encoding frame %3d (size=%5d): (ret=%d)\n", 1, pkt.size,ret);

  it runs for 2 or 3 time(during which if(got_output) is not true), then i get SIGSEGV. Tried addr2line and ndk-stack but no use[Though i enabled debug info, ndk-stack cannot find routine info].

  I edited libx264's encoder.c code with some fprintf statements.
  Posting snippet of code

     if( h->frames.i_input <= h->frames.i_delay + 1 - h->i_thread_frames )
  
      {
  
          /* Nothing yet to encode, waiting for filling of buffers */
  
          pic_out->i_type = X264_TYPE_AUTO;
  
  fprintf(stderr,"EditLog:: Returns as waiting for filling \n"); //edit
  
          return 0;
  
      }
  
  }
  
  
  
  else
  
  {
  
      /* signal kills for lookahead thread */
  
      x264_pthread_mutex_lock( &h->lookahead->ifbuf.mutex );
  
      h->lookahead->b_exit_thread = 1;
  
      x264_pthread_cond_broadcast( &h->lookahead->ifbuf.cv_fill );
  
      x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );
  
  }
  
  fprintf(stderr,"After wait for fill \n");
  
  fprintf(stderr,"h: %p \n",h); //edit
  
  fprintf(stderr,"h->i_frame = %p \n",&h->i_frame); //edit
  
  h->i_frame++;
  
  fprintf(stderr,"after i_frame++");

  in log, i don't see after i_frame++, here occurs (may be) the SIGSEGV.

  Please help in solving it. The same works without neon optimization !!

• Wrapping an h264 stream with ts (transport stream)

  20 août 2018, par ICU_

  Suppose I have an incoming stream of H264 data wrapped in RTP. After I strip the RTP header, how can I re-wrap it into a TS header (transport stream) for playing on the web browser ? I know Ffmpeg can do it, but am not on a windows or linux platform. So I need to manually do it. I would need a simple library in c or c++.