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• C++ How to make a rtsp stream buffer in RAM and write it to file if needed

  18 septembre 2023, par FenyaHere

  The task is to receive data from rtsp and without decoding keep last 60 seconds of it in RAM to save when needed. Right now i'm doing it with OpenCV, decode frames and keep a buffer of frames, so when event triggers i just copy the buffer, encode it and save to file. But current uses too much memory and CPU to decode/encode and keep unencoded frames.

  


  I've tried to look into gstreamer library but failed to come up with a solution (i'm new to gstreamer). Should i look more into gstreamer (gstreamer-1.0, RTSP H264 stream and shared memory for example) ? Are there easier ways to do it(found this : https://trac.ffmpeg.org/wiki/Capture/Lightning) ? Thank you for your help !

  


• Compiling custom FFMPEG

  25 novembre 2019, par Arttu

  I need to compile ffmpeg from source for CentOS. The goal it to convert MP3 and WAV to FLAC. I tried to compile ffmpeg with this guide : https://trac.ffmpeg.org/wiki/CompilationGuide/Centos
  and it worked fine, but took approximately 20min and compiled a bunch unnecessary things, even thought I did not used next options as recommended in guide, but used :

  PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure \
  
  --prefix="/opt/tmg/ffmpeg_build" \
  
  --pkg-config-flags="--static" \
  
  --extra-cflags="-I/opt/tmg/ffmpeg_build/include" \
  
  --extra-ldflags="-L/opt/tmg/ffmpeg_build/lib" \
  
  --extra-libs=-lpthread \
  
  --extra-libs=-lm \
  
  --bindir="/opt/tmg/ffmpeg_build/bin" \
  
  --enable-gpl \
  
  --enable-libfreetype

  My question is what do I need for MP3 and WAV to FLAC and how do I compile just that part ?

  I found in configuration --disable-all option, but what do I have to enable ?

  Thanks in advance.

• FFmpeg WebM AV1 Support

  6 septembre 2018, par Matt McManis

  With FFmpeg how can I use AV1 codec in a webm container ?

  I get the error :

  Only VP8 or VP9 video and Vorbis or Opus audio and WebVTT subtitles are supported for WebM.
  
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
  
  Error initializing output stream 0:0 --

  ---

  However Wikipedia says WebM supports AV1.

  https://en.wikipedia.org/wiki/AV1

  AV1 is intended to be able to be used together with the audio format Opus in a future version of the WebM container format for HTML5 web video

  Or can FFmpeg simply not encode this new version ?

  ---

  My settings :

  ffmpeg -y 
  
  
  
  -i "C:\Users\Matt\video.mp4" 
  
  
  
  -c:v libaom-av1 -strict experimental 
  
  -cpu-used 1 -crf 28 
  
  -pix_fmt yuv420p 
  
  -map 0:v:0? -map_chapters -1 
  
  -sn 
  
  
  
  -c:a libopus 
  
  -map 0:a:0? 
  
  
  
  -map_metadata 0 
  
  
  
  -f webm 
  
  
  
  -threads 0 
  
  
  
  "C:\Users\Matt\video.webm"