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• Linking VLC build to ffmpeg build libraries

  14 mars 2017, par gatorface

  I’m receiving the following error message when attempting to build VLC :

  checking for mad_bit_init in -lmad... yes
checking for MPG123... yes
checking for libavutil variant... libav
checking for GST_APP... yes
checking for GST_VIDEO... yes
checking for AVCODEC... no
configure: error: Requested 'libavcodec >= 57.16.0' but version of libavcodec is 56.1.0. Pass --disable-avcodec to ignore this error.

  I am running the command (first step of Configuration from link below, I did the contrib method and built everything else as well) :

  ./configure

  So let’s get the obvious out of the way : I’m missing the most recent version of libavcodec (v57). Using --disable-avcodec is not a viable solution. Doing a quick apt-file search libavcodec I’m seeing that for debian/jessie the latest version published is libavcodec56, not 57. I did also notice that libavcodec57 was available for installation with ffmpeg here https://ffmpeg.org/download.html

  I actually needed to also build ffmpeg from source. So I did that, worked my way through the dependencies without too much trouble using the guide linked to below.

  So here is my issue : After building and doing a make install of ffmpeg, I still get that error above, despite having the latest libavcodec freshly compiled.

  So my question is : since I used that guide, I am still getting the error when building vlc. I see that the lib exists her : /root/ffmpeg_build/lib/libavcodec.a, and I figured make install would put it where it needs to be. Is there some other compile flag I can set while compiling vlc to point it to that lib directory to look for libavcodec ?

  ffmpeg build : https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu
  vlc build : https://wiki.videolan.org/UnixCompile/

  ---

  UPDATE : tried this, still getting the error message : PKG_CONFIG_PATH="/root/ffmpeg_build/lib:$PKG_CONFIG_PATH" LD_LIBRARY_PATH="/root/ffmpeg_build/lib:$LD_LIBRARY_PATH" ./configure

  ---

  UPDATE2 : tried this, still getting the error message : ./configure --libdir="/root/ffmpeg_build/lib:$LIBDIR"

  ---

  UPDATE3 : I tried merging my ffmpeg libs into my vlc libs and may have made things worse. My ffmpeg libs lived here : /root/ffmpeg_build/lib
  My vlc build (contrib builds as well) lived here : /opt/vlc/

  So I merged them with my existing vlc contrib lib :

  cp /root/ffmpeg_build/lib/* /opt/vlc/contrib/x86_64-linux-gnu/lib/
cp /root/ffmpeg_build/lib/pkgconfig/* /opt/vlc/contrib/x86_64-linux-gnu/lib/pkgconfig/

  Then ran configure :
  ./configure --with-contrib=contrib/x86_64-linux-gnu

  Which finally worked, but now I get this error when I try to make :

  Now I get the error :
  /usr/bin/ld: /opt/vlc/contrib/x86_64-linux-gnu/lib/libavformat.a(allformats.o): relocation R_X86_64_32 against `ff_a64_muxer' can not be used when making a shared object; recompile with -fPIC

• Download RTSP recording content between two dates and times, or from start seconds to end seconds

  23 septembre 2022, par holt2

  I need to download from an RTSP link the content recorded on an IP camera from a start and end date and time. It would also be valid to be able to download it from X seconds of start of the recording to seconds of end.

  


  With this ffmpeg command I download the recording content from the RTSP link only from the beginning of the recording content, with the duration in seconds passed by the -t parameter :

  


  ffmpeg -rtsp_transport tcp -i  -r 30 -t <seconds> -y -vf scale=800:-1 -c:v libx264 -crf 20 -preset fast -c:a aac -strict experimental -b:a 192k -ac 2 /path/to/video/filename.mp4&#xA;</seconds>

  


  I tried to download with ffmpeg the content using temporary media fragment URIs (https://www.w3.org/2008/WebVideo/Fragments/wiki/UA_Server_RTSP_Communication#.281.29_Temporal_Media_Fragment_URIs) but it doesn't do it correctly :

  


  ffmpeg -rtsp_transport tcp -i #t=10,20 -r 30 -y -vf scale=800:-1 -c:v libx264 -crf 20 -preset fast -c:a aac -strict experimental -b:a 192k -ac 2 -ss 19:09:13 -t 5 /path/to/video/filename.mp4


  


  I have also tried with ffmpeg to use the -ss parameter to try to extract the recording from a specific hour, minute and second (https://trac.ffmpeg.org/wiki/Seeking) but when running it gets stuck, it does not advance :

  


  ffmpeg -rtsp_transport tcp -i  -r 30 -y -vf scale=800:-1 -c:v libx264 -crf 20 -preset fast -c:a aac -strict experimental -b:a 192k -ac 2 -ss 19:09:13 -t <seconds> /path/to/video/filename.mp4&#xA;</seconds>

  


  In case it's helpful, to get the RTSP link, I'm using the ONVIF protocol with a NodeJS library (https://github.com/agsh/onvif). I have also reviewed the ONVIF documentation available but have not found a way to download recorded content between start and end dates and times.

  


  Do you know how to download from an RTSP link the content recorded on an IP camera from a start date and time and end date, or download it from X seconds of recording start to seconds of end ?

  


  I am also open to use other tools or commands that can do this.

  


• Data URI or Base64 string as input to ffmpeg command

  18 août 2022, par Alok

  I can easily convert my media from one format to other using ffmpeg
  
ffmpeg -i input_file.ogg -acodec flac output_file.flac

  


  In place of input file I want to use Data URI or Base64 string as input file. I saw one example
  
ffmpeg -i "data:image/gif;base64,R0lGODdhCAAIAMIEAAAAAAAA//8AAP//AP///////////////ywAAAAACAAIAAADF0gEDLojDgdGiJdJqUX02iB4E8Q9jUMkADs=" smiley.png given at https://ffmpeg.org/ffmpeg-all.html

  


  I tried this example for my audio conversion.
  
ffmpeg -i "data:audio/ogg; codecs=opus;base64,GkXfo59ChoEBQveBAULygQR...trimmed" -acodec flac /tmp/alok.flac

  


  When I run script having this command I see error
  
./ffmpeg.sh: line 1: /usr/bin/ffmpeg: Argument list too long

  


  How can I make this conversion work ? How can I use Base64 data as input to ffmpeg command ?