Recherche avancée

Sur d’autres sites (13083)

• crystalhd : Revert back to letting hardware handle packed b-frames

  16 octobre 2016, par Philip Langdale

  crystalhd : Revert back to letting hardware handle packed b-frames
  I’m not sure why, but the mpeg4_unpack_bframes bsf is not
  
  interacting well with seeking. Looking at the code, it should be
  
  ok, with possibly one warning shown, but I see it getting stuck
  
  for an extended period of time after a seek where a packed frame
  
  is cached to be shown later.
  So, I gave up on that and went back to making the old hardware
  
  based path work. Turns out that it wasn’t broken except that some
  
  samples have a 6 byte drop packet which I wasn’t accounting for.
  Now it works again and seeks are good.
  

  • [DH] libavcodec/crystalhd.c

• Using ffmpeg to encode web dash and audio drift

  1er octobre 2016, par John Joske

  I’m trying to use ffmpeg to create webm-dash encoded files from a usb web cam. Adapted from this example http://wiki.webmproject.org/adaptive-streaming/instructions-to-do-webm-live-streaming-via-dash

  I have managed to get something nearly works with the following command :

  ffmpeg -f video4linux2 -framerate 30 -s 640x360 -i /dev/video0
  -thread_queue_size 512 -f alsa -ar 44100 -ac 2 -i hw:2 -map 0:0 -pix_fmt yuv420p -c:v libvpx-vp9 -s 640x360 -keyint_min 60 -g 60 -speed 6 -tile-columns 4 -frame-parallel
  1 -threads 8 -static-thresh 0 -max-intra-rate 300 -deadline realtime
  -lag-in-frames 0 -error-resilient 1 -f webm_chunk -header video_360.hdr" -chunk_start_index 1 video_360_%d.chk -map 1:0 -c:a libvorbis -b:a 128k -ar 44100
  -f webm_chunk -copytb 1 -audio_chunk_duration 2000 -header video_171.hdr -chunk_start_index 1 video_171_%d.chk

  However over a period of time the audio chunks slowly get behind the video chunks, can anyone suggest a way to ensure they stay the same.

• Facebook live video can only be previewed while streaming my Mac screen

  24 janvier 2017, par iownthegame

  I use the following ffmpeg command to share my screen streaming to Facebook.

  

  ffmpeg -f avfoundation -r 10 -video_size 352x288 -i "0" -c:v h264 -f flv 
  
  "rtmp://rtmp-api.facebook.com:80/rtmp/1269140699772419?ds=1&a=AaYsXcYcdHQrrrUF"

  then I can see the video preview scenes
  

  however, once I press the ’Go Live’ button, and go to my facebook page, I can find a post said I am Live Now. When I press the ’play button’, there are only black scenes that last for 1 2 seconds, and the video ends.

  

  And there is also a weird thing, the video can be played when I end up the live stream. When refreshing the page, I can find a post said I was Live, the video of this post can be played successfully.

  Anyone knows why the video can be watched when previewing and finishing live but not the exact live moment ?

  [updated]

  During the live streaming period, if I press the play button, there are only 1 2 seconds black scenes and the live stream ends.
  

  However if I press the video frame again, another modal pops up then I can see the live streaming. Is it a facebook bug ?