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• ffmpeg convert hevc to h264 wrong duration

  17 septembre 2021, par Vinh Duy

  I converted an HEVC file to H264 by ffmpeg, but result in wrong duration.
HEVC file duration is 3m32 but H264 file is 9h long. If I skip audio with '-an' parameter, output file duration is matched.
VLC can play but embedded into webpage causes forever loading.

  


  Could anyone help me with this error ?

  


  Check HEVC with ffprobe :

  


  ffprobe -i hevc.mp4
ffprobe version 4.2.4-1ubuntu0.1 Copyright (c) 2007-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'hevc.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    title           : Media Presentation
    encoder         : Lavf58.29.100
  Duration: 00:03:32.16, start: 0.000000, bitrate: 1653 kb/s
    Stream #0:0(und): Video: hevc (Main) (hev1 / 0x31766568), yuvj420p(pc, bt709), 1920x1080, 1616 kb/s, 24.99 fps, 25 tbr, 90k tbn, 90k tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 16000 Hz, mono, fltp, 31 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


  


  check H264 file :

  


  ffprobe -i h264.mp4
ffprobe version 4.2.4-1ubuntu0.1 Copyright (c) 2007-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'h264.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    title           : Media Presentation
    encoder         : Lavf58.29.100
  Duration: 09:03:59.97, start: 0.000000, bitrate: 12 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 1975 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 16000 Hz, mono, fltp (default)
    Metadata:
      handler_name    : SoundHandler


  


  convert command :

  


  ffmpeg -i hevc.mp4 -c:a copy -c:v libx264 h264.mp4


  


• Can ffmpeg seek when using an input stream (or url) ?

  27 juin 2022, par Roee

  I've been using ffmpeg quite a lot in the past few weeks, and recently I've encountered a very annoying issue - when I use ffmpeg with an input stream (usually, just a url as the input) and try to set a start time (with -ss option), I always get a warn message that says "could not seek to position : XXX".

  



  Then, ffmpeg just starts to download the file, and it ouputs nothing until it has downloaded enough data and got to my desired start time.

  



  I'll give an example :

  



  I use this command to execute ffmpeg :

  



  ffmpeg -ss 50 -re -i https://ascent.usbank.com/acp/videos/041114ascent.flv -b:a 128k -ac 2 -acodec libvorbis -b:v 1024k -vcodec libtheora -strict 2 -preset ultrafast -tune zerolatency -pix_fmt yuv420p -f ogg pipe:1


  



  and I get the warn message

  



  https://ascent.usbank.com/acp/videos/041114ascent.flv: could not seek to position 50.000


  



  Then, it takes about 30 seconds until ffmpeg starts to output data to stdout. And when I try this with longer videos (and longer seek times), it takes even longer.

  



  My question is, what can I do ? I guess it's impossible for ffmpeg to seek when it haven't got the whole input stream... Am I wrong ? Or is there any other solution ?

  



  Of course I try to avoid downloading the entire file from the web...

  



  Thanks in advance !

  



  Roee.

  


• Link error when compiling opencv from source when including ffmpeg compiled from source

  17 septembre 2021, par Drew

  I've been stuck on this problem for weeks.

  


  I'm trying to build opencv on a raspberry pi 4 with x264 support. To do this I need to include ffmpeg, and also build that from source.

  


  However when compiling opencv, I'm consistently getting these linker errors :

  


  /usr/bin/ld: ../../lib/libopencv_videoio.so.4.5.3: undefined reference to `avcodec_get_context_defaults3'
/usr/bin/ld: ../../lib/libopencv_videoio.so.4.5.3: undefined reference to `av_lockmgr_register'
/usr/bin/ld: ../../lib/libopencv_videoio.so.4.5.3: undefined reference to `av_register_all'


  


  I'm new to Linux, so I'm not exactly sure how to get started troubleshooting this. I believe I have ffmpeg correctly compiled and installed.

  


  Here's the steps I use :

  


  Configure ffmpeg :

  


  sudo ./configure \
--prefix=/usr \
--extra-ldflags="-latomic" \
--enable-shared \
--extra-libs='-lpthread -lm' \
--ld=g++ \
--enable-gpl \
--disable-debug \
--enable-nonfree \
--enable-libx264 \
--enable-omx \
--enable-omx-rpi \
--enable-gnutls \
--enable-libfreetype \
--enable-libmp3lame


  


  Then build it :
sudo make -j4

  


  Then install it as a package : (so opencv cmake will detect it)

  


  sudo checkinstall -y --deldoc=yes --pkgversion=9999 --pkgname=ffmpeg


  


  Then configure opencv (ffmpeg is detected)

  


  sudo cmake ../opencv_sources -D CMAKE_BUILD_TYPE=RELEASE \
-D OPENCV_EXTRA_MODULES_PATH= $PWD/../opencv_contrib/modules \
-D ENABLE_NEON=ON \
-D ENABLE_VFPV3=ON \
-D BUILD_TESTS=ON \
-D INSTALL_PYTHON_EXAMPLES=OFF \
-D OPENCV_ENABLE_NONFREE=ON \
-D CMAKE_SHARED_LINKER_FLAGS='-latomic -L/usr/lib' \
-D WITH_V4L=ON \
-D WITH_QT=OFF \
-D BUILD_EXAMPLES=OFF \
-D CPU_BASELINE=NATIVE \
-D CMAKE_INSTALL_PREFIX="$HOME/opencv_build" \
-D BUILD_opencv_apps=OFF \
-D BUILD_opencv_python2=OFF \
-D BUILD_SHARED_LIBS=ON \
-D WITH_FFMPEG=ON


  


  Then build opencv :

  


  sudo make -j4


  


  And this is where I get linking errors.

  


  I checked in /usr/lib and the .so files appear to be there :

  


  ls /usr/lib | grep libav

libavcodec.a
libavcodec.so
libavcodec.so.59
libavcodec.so.59.4.101
libavdevice.a
libavdevice.so
libavdevice.so.59
libavdevice.so.59.0.100
libavfilter.a
libavfilter.so
libavfilter.so.8
libavfilter.so.8.1.103
libavformat.a
libavformat.so
libavformat.so.59
libavformat.so.59.4.101
libavutil.a
libavutil.so
libavutil.so.57
libavutil.so.57.3.100


  


  How do check where opencv is looking when linking ? And is there a way I can check the shared libraries that ffmpeg generated to make sure they work ?

  


  The ffmpeg version is : git-2021-08-10-c245963

  


  And opencv is 4.5.3-dev