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• How to add a Poster Frame to an MP4 video by timecode ?

  25 mai 2020, par Crissov

  The mvhd atom or box of the original Quicktime MOV format supports a poster time variable for a timecode to use as a poster frame that can be used in preview scenarios as a thumbnail image or cover picture. As far as I can tell, the ISOBMFF-based MP4 format (.m4v) has inherited this feature, but I cannot find a way to set it using FFmpeg or MP4box or similar cross-platform CLI software. Edit : Actually, neither ISOBMFF nor MP4 imports this feature from MOV. Is there any other way to achieve this, e.g. using something like HEIFʼs derived images with a thmb (see Amendment 2) role ?

  



  

  



  The original Apple Quicktime (Pro) editor did have a menu option for doing just that. (Apple Compressor and Photos could do it, too).

  



  

  



  To be clear, I do not want to attach a separate image file, which could possibly be a screenshot grabbed from a movie still, as a separate track to the multimedia container. I know how to do that :

  



  

  • Stackoverflow #54717175

  


  • Superuser #597945

  


  



  I also know that some people used to copy the designated poster frame from its original position to the very first frame, but many automatically generated previews use a later time index, e.g. from 10 seconds, 30 seconds, 10% or 50% into the video stream.

  


• Reduce compiled ffmpeg library size based on what I need

  20 septembre 2014, par Alin

  I finally managed to build ffmpeg as detailed in here : https://enoent.fr/blog/2014/06/20/compile-ffmpeg-for-android/ and in the end, I have a ffmpeg library which accepts command arguments.

  I am ONLY applying a watermark image over the video so for it I am using this ffmpeg command :

  ffmpeg -i input.avi -i logo.png -filter_complex 'overlay=10:main_h-overlay_h-10' output.avi

  Basic config :

    ./configure \
  
      --prefix=$PREFIX \
  
      --disable-shared \
  
      --enable-static \
  
      --disable-doc \
  
      --disable-ffmpeg \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-ffserver \
  
      --disable-doc \
  
      --disable-symver \
  
      --enable-protocol=concat \
  
      --enable-protocol=file \
  
      --enable-muxer=mp4 \
  
      --enable-demuxer=mpegts \
  
      --enable-memalign-hack \
  
      --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
      --target-os=linux \
  
      --arch=arm \
  
      --enable-cross-compile \
  
      --sysroot=$SYSROOT \
  
      --extra-cflags="-Os -fpic -marm $ADDI_CFLAGS" \
  
      --extra-ldflags="$ADDI_LDFLAGS"

  No other commands needed from ffmpeg.

  When compiling ffmpeg I get these files :

  

  I want to reduce the size of the library to as small as possible, so given the above command, are there any files that I can remove from final build ?

  ALSO which is the most common CPU found in current devices ? arm v7vfpv3, arm v7vfp, arm v7n ? I want to cover as many devices as possible.

  #arm v6
  
  #CPU=armv6
  
  #OPTIMIZE_CFLAGS="-marm -march=$CPU"
  
  #PREFIX=./android/$CPU 
  
  #ADDITIONAL_CONFIGURE_FLAG=
  
  #build_one
  
  
  
  #arm v7vfpv3
  
  CPU=armv7-a
  
  OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "
  
  PREFIX=./android/$CPU
  
  ADDITIONAL_CONFIGURE_FLAG=
  
  build_one
  
  
  
  #arm v7vfp
  
  #CPU=armv7-a
  
  #OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "
  
  #PREFIX=./android/$CPU-vfp
  
  #ADDITIONAL_CONFIGURE_FLAG=
  
  #build_one
  
  
  
  #arm v7n
  
  #CPU=armv7-a
  
  #OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mtune=cortex-a8"
  
  #PREFIX=./android/$CPU 
  
  #ADDITIONAL_CONFIGURE_FLAG=--enable-neon
  
  #build_one
  
  
  
  #arm v6+vfp
  
  #CPU=armv6
  
  #OPTIMIZE_CFLAGS="-DCMP_HAVE_VFP -mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU"
  
  #PREFIX=./android/${CPU}_vfp 
  
  #ADDITIONAL_CONFIGURE_FLAG=
  
  #build_one

• txd : Use the TextureDSP module for decoding

  20 mai 2015, par Vittorio Giovara

  txd : Use the TextureDSP module for decoding
  Using the internal DXTC routines brings support for non multiple of 4
  
  textures. A new test is added to cover this feature. Hashes differ
  
  since the decoding algorithm is different, though no visual changes
  
  have been spotted.
  Signed-off-by : Vittorio Giovara <vittorio.giovara@gmail.com>
  

  • [DBH] configure
  • [DBH] libavcodec/Makefile
  • [DBH] libavcodec/s3tc.c
  • [DBH] libavcodec/s3tc.h
  • [DBH] libavcodec/txd.c
  • [DBH] tests/fate/video.mak
  • [DBH] tests/ref/fate/txd-16bpp
  • [DBH] tests/ref/fate/txd-odd