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• Streaming a webcam to a web server to be streamed on web

  19 octobre 2012, par gazzwi86

  I intend on streaming a web cam from a Raspberry Pi to a server, which can then serve the stream up to users over the web. I would ideally like the stream to work across all browsers with minimal complication, so the current mjpeg format I presume would not be ideal.

  Firstly, I would like to know if ffmpeg is the right tool for the job as its what I'm experimenting with at the moment ? I also looked at using ffmpeg and motion but didnt see the need for motion as I don't need motion detection. My config for ffmpeg is listed below :

  I installed via apt-get :

  apt-get install ffmpeg

  I have create a config file /etc/ffserver.conf containing the following :

  Port 80
  
  BindAddress 0.0.0.0
  
  MaxClients 10
  
  MaxBandwidth 50000
  
  NoDaemon
  
  
  
  <feed>
  
      file /tmp/webcam.ffm
  
      FileMaxSize 10M
  
  </feed>
  
  
  
  <stream>
  
      Feed webcam.ffm
  
      Format mpjpeg
  
      VideoSize 640x480
  
      VideoFrameRate 15
  
      VideoBitRate 2000
  
      VideoQMin 1
  
      VideoQMax 10
  
      strict -1
  
  </stream>

  I have created a file in the sbin called webcam.sh containing the following :

  ffserver -f /etc/ffserver.conf & ffmpeg -v verbose -r 5 -s 640x480 -f video4linux2 -i /dev/video0 http://localhost/webcam.ffm

  Running the above starts the stream but at the moment viewing http://webcam.mjpeg starts a file downloading which seems not to start in chrome and doing the same with and html file with the stream in a img tag doesnt work.

• Transcode to ogg or webm, writing the file as it goes

  22 juillet 2020, par Mark Smith

  I need to transcode files (mp3, flac, m4a and others) to ogg or webm. (This is because I need them to play on Firefox 60.9 which does not support most of these, and flacs are too large. I cannot update the browser.)

  


  ffmpeg can do the transcoding, but when transcoding to ogg or webm, depending on the exact configuration, either 0 bytes or a few kB is written immediately, and then nothing more until the transcoding is complete (even using -flush_packets 1) — hence I cannot start playing the audio.

  


  By comparison, if I transcode to mp3, the file is written progressively and I can start playing immediately.

  


  Is it possible to transcode to ogg or webm in such a way that the file is written as the transcoding happens, and I can start playing it (almost) immediately ?

  


  Configurations I have tried :

  


  ffmpeg -i orig.m4a -c:a libvorbis -flush_packets 1 vorbis.ogg
ffmpeg -i orig.m4a -c:a libopus -flush_packets 1 opus.ogg
ffmpeg -i orig.m4a -c:a libvorbis -flush_packets 1 vorbis.webm
ffmpeg -i orig.m4a -c:a libopus -flush_packets 1 opus.webm


  


  This is running on Debian (Raspian stretch, specifically) and I would like to do it without adding dependencies from outside of the Debian/Raspian archives, if possible. Sticking with ffmpeg would be my ideal choice but will consider others.

  


• libavcodec/tiff : Process SubIFDs tag with multiple entries

  30 mai 2019, par Nick Renieris

  libavcodec/tiff : Process SubIFDs tag with multiple entries
  SubIFDs that were part of more than single-sized "SubIFDs" tags were
  
  being ignored due to existing code ignoring that case.
  This patch makes is so the first entry is read, which is not ideal
  
  but enough for some DNG images present in the wild to be decodeable
  
  More specifically, the first SubIFD which we would process with this
  
  patch is the main image and the second one is a second thumbnail,
  
  which is not as important to decode.
  In DNG images with the .tiff extension, it solves the issue where
  
  the TIFF thumbnail in IFD 0 was incorrectly parsed (related
  
  confusion : [1]).
  Embedded thumbnails for DNG images can still be decoded with the
  
  "-thumbnail" option.
  Related to ticket : https://trac.ffmpeg.org/ticket/4364
  [1] : https://superuser.com/questions/546879/creating-video-from-dng-images-with-ffmpeg
  Signed-off-by : Nick Renieris <velocityra@gmail.com>
  

  • [DH] libavcodec/tiff.c