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• ffmpeg mp4 to webm through icecast server livestream

  24 juin 2021, par Aporie

  I'm trying to stream huge MP4 videos (2.5Go) on an icecast server. After playing a lot with ffmpeg options to get the best quality/speed encoding settings, I'm facing a strange issue.

  



  If I launch my ffmpeg streaming and load the video in the browser I can see it, but if I try to join it after 30s, I just get a black screen with the bottom video player bar.

  



  Is there somewhere we can see errors ? And where ? I don't really get if the error is coming from ffmpeg / icecast / my web browser ...

  



  If somebody can give me a clue.

  



  Here is my setup on ffmpeg :

  



  ./ffmpeg -i stream/my_video.mp4 \
        -acodec libopus -b:a 64k \
        -vcodec libvpx -b:v 500K -crf 25 -vf scale=640:360 -content_type video/webm \
        -loop 365 \
        icecast://source:Password@server:8000/live.webm


  


• MPEG-DASH not working. MPD validation fails

  16 novembre 2017, par Marko36

  I am trying to serve video using MPEG-DASH. No success. I have tried the following :

  Following the instructions on webproject.org, using FFMPEG, I have created several variants of the original video and the DASH MPD manifest, containing metadata. However, the manifest does not validate using http://dashif.org/conformance.html. This validator itself is quite useless, as it provides unusable info about the error. I have found in a post from 2014, that one of the errors generated by FFMPEG is capital letters in some metadata (not a critical one, but could have been fixed for years !). Other errors detected, but not described. No tangible info from any of these other validators either : http://www-itec.uni-klu.ac.at/dash/?page_id=605 (produces rubbish info), https://github.com/Eyevinn/dash-validator-js (throws an exception)

  Following instructions on mozilla.org, produces the same non-working result, as the instructions are nearly identical (including same resolution*bitrate sets), except that Mozilla omits the use of dash.js, which is deemed necessary by the rest of the internet.

  This guide on Bitmovin, utilizing x264 and MP4Box does not work either. Going by the instructions, I have to recode the original x264 video twice. The final version of videos are in some cases twice the size of their intermediate versions and 720p video is actually larger than its 1080p, higher bitrate counterpart. No need to go further. (Yet, this is the only way that actually produced segments..)

  I have spent 3 days on the above, read about all there is on the web from the other frustrated adopters, and ran out of options. I would really apreciate some pro tips ! Thanks !

• sync dumped rtp streams [duplicate]

  2 octobre 2017, par Pawel K

  This question already has an answer here :

  • Read dumepd RTP stream in libav
    
    1 answer
    

  I need a bit of a guidance. I am writing a bit of an application to parse two streams of RTP data to get the actual video (h264) and audio (PCM alaw), it’s not a RTSP client but a rather dump parser (Interleved RTP/RTCP).
  Question is now how to synchronise these both streams ?

  I know I need to do some calculations between timestamps from packets and NTP from RTCP (I research it currently) but what then how to prepare two tracks to mux them into some container like matroska (using for instance ffmpeg) ? Do I have to create some empty frames for audio to lengthen it or stretch somehow I don’t have a clue how to approach it.