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• How can I get ffmpeg to start downloading a stream at a specific time ?

  9 mai 2019, par FiskFan1999

  If I know that a livestream is starting in a few hours, and I know the url of the livestream. If the stream is currently happening I have no problem using ffmpeg to save the stream to file. However, I am currently looking all over the web to find if there is a way for me to schedule a command to execute in the future. I have tried using "at", but that still seems to run the command in the present. I am wondering if "at" is the answer to my problem or if it is something else ? Thank you.

  I have tried using the at command and looking for other applications on MacOS to schedule commands.

  Here is an example of the ffmpeg command that works perfectly for my intentions when I type it into the command line at present. What I am hoping is that I can get ffmpeg to start reading from the stream at a specific date and time and start writing to file from there.

  ffmpeg -loglevel panic -nostdin -i [WEB_URL] -c:a aac -b:a 320k -crf 33 out.mp4

  Here is my unsuccessful attempt to use at :

  at 22:53; ffmpeg -loglevel panic -nostdin -i [WEB_URL] -c:a aac -b:a 320k -crf 33 out.mp4 & 

  What I expected was for ffmpeg to work as if I had entered in the command at the instant I scheduled the job for. However, ffmpeg started working immediately.

• Where can I get 16-bit video sequences ? [on hold]

  9 mai 2017, par govind

  I understand that I can create 16-bit videos from 8-bit ones, but I want to work on actual 16-bit data (for a class project) and not just the bit-shifted pixel values. I just want to extract and work on the 16-bit Luma component from the video.

  https://media.xiph.org/ has 16-bit raw contents but the file size is 500GB. I would like to limit my downloads to 1-2 GB.
  The footnote at https://media.xiph.org/video/derf/ says "These were converted from 16-bit linear RGB to Y’CbCr", can I get the source from which these conversion took place.

  I could create my own content with some custom pattern but that’s not an option since I want to work on natural-looking imagery.

  I do understand that regular monitors can only display 8-bit. I also understand that it’s not a typical StackOverflow question, but I have already spent 2 hours online searching for it. Any links will be appreciated. Thanks in advance.

• avformat/flvenc : avoid 24bit timestamp truncation for FLV metadata

  26 novembre 2021, par asilvestre

  avformat/flvenc : avoid 24bit timestamp truncation for FLV metadata
  FLV AMF tags have a 24bit field for timestamps plus an 8bit for extended
  
  timestamps.
  All FLV AMF tags except when we write metadata handle this correctly
  
  using the put_timestamp function.
  Until now when writing metadata we were only using the first
  
  24 bits and thus the timestamp value was wraping around 4 hours 40
  
  minutes (16,800,000 ms, max 24 bit value 16,777,216) of playback.
  This commit fixes this applying this same function put_timestamp
  
  for the metadata FLV tag.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavformat/flvenc.c