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• How to use ffmpeg to stream a playlist of clips that are in very different formats ? [closed]

  21 septembre 2024, par gulagkulak

  I'm trying to use ffmpeg to stream a playlist of video files that are all in very different formats, sizes, and aspect ratios.

  


  The problem is that often when the video changes I get a spinning wheel of death on the target streaming sites and some kinda error in the ffmpeg output.

  


  Sometimes it's [flv @ 0x7f5c10686200] Failed to update header with correct duration.

  


  Or [flv @ 0x7f5c10686200] Failed to update header with correct filesize.

  


  Or a whole bunch of [aost#0:1/aac @ 0x8947680] Non-monotonic DTS; previous: 82536459, current: 78988751; changing to 82536460. This may result in incorrect timestamps in the output file.

  


  Or it starts dropping every single frame. I think it happens when it changes from a progressive to deinterlaced file or vice-versa.

  


  How do I make ffmpeg more resilient so it can handle every kind of file thrown at it and output a continuous stream at 1920x1080 and 30fps h264 to a streaming server ?

  


  This is the command I'm using :

  


  ffmpeg -stream_loop -1 -re -f concat -i playlist.txt -threads 4 -c:v libx264 -preset ultrafast \
-b:v 2000k -maxrate 2000k -g 30 -c:a aac -b:a 128k -strict -2 -fflags +genpts+discardcorrupt \
-async 1 -map 0 -r 30 -s 1920x1080 -bufsize 6000k -flags +cgop -fflags +igndts \
-f tee -rtsp_transport tcp -max_delay 1000 \
"[f=flv:onfail=ignore]rtmp://xxxxxxxxxxxxxxx.com/live/xxxxxxxxxxxxxxx|[f=flv:onfail=ignore]rtmp://xxxxxxxxxxxxxxx.com/live/xxxxxxxxxxxxxxx"


  


  And it's not working. ffmpeg just fails in a variety of ways. I've spent two days trying to figure this out.

  


  Even used handbrake to try and pre-encode the video files to the same exact format, but even then ffmpeg fails in similar ways, just less often.

  


  After re-encoding with handbrake I tried to concat the videos together with ffmpeg and ended up with a large video where the sound breaks for some parts of it and it stops being seekable in VLC after a certain timecode.

  


  I think I'm missing some important ffmpeg flag or option.

  


• NodeJS piping with ffmpeg

  8 février 2014, par Gnap

  I wanted to do a HTTP live stream on a screen cast with using ffmpeg, nodejs and html5 . I wanted it to be as real time as possible. However, I find that my video received by the client was behind by 1 2 seconds (On Chrome/Chromium). I am using vp8/webm as my codec.

  I have eliminated the following factors as such :
  1) Network : I have tried serving and receiving the video file locally by stating the video source to be 127.0.0.1:PORT or localhost:PORT
  2) ffmpeg encoding speed:I have tried outputting the file locally, it the "delay" seems to be negligible.
  3) Chrome internal buffer. The buffer was accounted to be 0.07s 0.08s.

  On the nodeJS side, I have a child process that runs the ffmpeg command, and did a ffmpeg.stdout.pipe(res) ; <— ffmpeg is child_process.spawn(...)

  So it seems that the ffmpeg.std.pipe(res) of nodejs seems to be the one delaying the video stream. Am I correct in assuming so ? Is there anyway that I may reduce the delay ?

• avutil/aes : Don't use out-of-bounds index

  21 octobre 2022, par Andreas Rheinhardt

  avutil/aes : Don't use out-of-bounds index
  Up until now, av_aes_init() uses a->round_key[0].u8 + t
  
  as dst of memcpy where it is intended for t to greater
  
  than 16 (u8 is an uint8_t[16]) ; given that round_key itself
  
  is an array, it is actually intended for the dst to be
  
  in a latter round_key member. To do this properly,
  
  just cast a->round_key to unsigned char*.
  This fixes the srtp, aes, aes_ctr, mov-3elist-encrypted,
  
  mov-frag-encrypted and mov-tenc-only-encrypted
  
  FATE-tests with (Clang-)UBSan.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavutil/aes.c