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• What's the difference with crf and qp in ffmpeg ?

  18 novembre 2016, par Nova

  After browsing around Google, I’ve came across this page about h264 encoding and discovered about qp. https://trac.ffmpeg.org/wiki/Encode/H.264

  My questions are : What are the differences with crf and qp ? Is it better to use qp over crf overall, or is it only if for using qp 0 for best lossless ? Does qp have a known sensible setting if it’s preferred ? So far, I know crf has the default value of 23 while 18 is a sensible preferred increase in quality, although I don’t understand why 18 wouldn’t be default if better sensible lossless. Lastly, would changing either of them cause incompatibility with non-ffmpeg players or just qp ?

  I’m converting from webm to mp4 by the way.

  I was going to test crf 23 and 18 and pick which is best but I can’t seem to find any concrete information on this comparison or about qp.

• Lego Mindstorms RSO Format

  14 juillet 2010, par Multimedia Mike — General

  I recently read a magazine article about Lego Mindstorms. Naturally, the item that caught my eye was the mention of a bit of Lego software that converts various audio file formats to a custom format called RSO that can be downloaded into a Mindstorms project to make the creation output audio. To read different sources, one might be left with the impression that there is something super-duper top secret proprietary about the format. Such impressions do not hold up under casual analysis of a sample file.

  A Google search for "filetype:rso" yielded a few pre-made sample that I have mirrored into the samples archive. The format appears to be an 8-byte header followed by unsigned, 8-bit PCM. More on the wiki. If FFmpeg could gain an RSO file muxer, that would presumably be a heroic feat to the Lego hacking community.

• FFMPEG Install/enable 'libfdk_aac' after installed FFMPEG via PPA

  18 juillet 2017, par Cyberbob

  I have linux MINT 17.3 Kernel 4.4.0-81 all update available. (For different reasons I can’t move to newer version of ubuntu/mint)

  I have installed FFMPEG via PPA (NOT from compiling the source) :

  sudo add-apt-repository ppa:jonathonf/ffmpeg-3 -y
  
  sudo apt-get update
  
  sudo apt-get install -y ffmpeg

  Then I tried to install libfdk-aac with guide :
  https://trac.ffmpeg.org/wiki/CompilationGuide/Quick/libfdk-aac

  sudo apt-get install pkg-config autoconf automake libtool
  
  git clone https://github.com/mstorsjo/fdk-aac.git
  
  cd fdk-aac
  
  ./autogen.sh
  
  ./configure --enable-shared --enable-static
  
  make
  
  sudo make install
  
  sudo ldconfig

  But I’m still receive from FFMPEG : "unknown encoder ’libfdk_aac’"

  How can I check if "libfdk_aac’ is correctly installed and HOW CAN I ACTIVATE / ENABLE the ’libfdk_aac’ on FFMPEG ?

  If is not possible in my situation, and if I’m obliged to remove all ffmpeg and follow this :
  https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu