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• Is it possible to redirect the messages libffmpeg prints to stderr ?

  11 mars, par wallefan

  I'm writing a program that uses libffmpeg to do some transcoding internally, but I find it has a tendency to print a lot of things to the process's stderr. I want to redirect those messages somewhere more intelligent.

  


  To be clear, I am NOT talking about spawning the ffmpeg executable as a subprocess and redirecting its stdio ! That is trivial in any programming language. I'm using ffmpeg as a C library (well, Rust bindings around a C library in my case) and I'm wondering if libffmpeg provides a hook for writing to stderr that I can override.

  


  If no such hook exists, would my best bet be to fork a child process with stdio redirection and only use libffmpeg from that subprocess ? That feels really hacky to me, especially since it would be really nice to not have to send the results libffmpeg spits out across a process boundary.

  


• Am I missing a timeout param in FFMPEG ?

  5 mai 2020, par Dave Stein

  I'm running an ffmpeg command like this :

  



  ffmpeg -loglevel quiet -report -timelimit 15 -timeout 10 -protocol_whitelist file,http,https,tcp,tls,crypto -i ${inputFile} -vframes 1 ${outputFile} -y

  



  This is running in an AWS Lambda function. My Lambda timeout is at 30 seconds. For some reason I am getting "Task timed out" messages still. I should note I log before and after the command, so I know it's timing out during this task.

  



  Update

  



  In terms of the entire lambda execution I do the following :

  



  


  • Invoke a lambda to get an access token. This lambda makes on API request. It has a timeout of 5 seconds. The max time was 660MS for one request.

  


  • Make another API request to verify data. The max time was 1.6 seconds.

  


  • Run FFMPEG

  


  



  timelimit is supposed to Exit after ffmpeg has been running for duration seconds in CPU user time.. Theoretically this shouldn't run more than 15 seconds then, plus maybe 2-3 more before the other requests.

  



  timeout is probably superfluous here. There were a lot of definitions for it in the manual, but I think that was mainly waiting on input ? Either way, I'd think timelimit would cover my bases.

  



  Update 2

  



  I checked my debug log and saw this :

  



  Reading option '-timelimit' ... matched as option 'timelimit' (set max runtime in seconds) with argument '15'.
Reading option '-timeout' ... matched as AVOption 'timeout' with argument '10'.


  



  Seems both options are supported by my build

  



  Update 2

  



  I have updated my code with a lot of logs. I definitively see the FFMPEG command as the last thing that executes, before stalling out for the 30 second timeout

  



  Update 3
I can reproduce the behavior by pointing at a track instead of full manifest. I have set the command to this :

  



  ffmpeg -loglevel debug -timelimit 5 -timeout 5  -i 'https://streamprod-eastus-streamprodeastus-usea.streaming.media.azure.net/0c495135-95fa-48ec-a258-4ba40262e1be/23ab167b-9fec-439e-b447-d355ff5705df.ism/QualityLevels(200000)/Manifest(video,format=m3u8-aapl)' -vframes 1 temp.jpg -y

  



  A few things here :

  



  

  1. I typically point at the actual manifest (not the track), and things usually run much faster

  


  2. I have lowered the timelimit and timeout to 5. Despite this, when i run a timer, the command runs for 15 seconds every time. It outputs a bunch of errors, likely due to this being track rather than full manifest, and then spits out the desired image.

  


  



  The full output is at https://gist.github.com/DaveStein/b3803f925d64dd96cd45ae9db5e5a4d0

  


• hwcontext_vulkan : improve public header documentation

  22 mai 2020, par Lynne

  hwcontext_vulkan : improve public header documentation
  Some things like using ImageLists were from a really old version that
  
  still used multiplanar images.
  

  • [DH] libavutil/hwcontext_vulkan.h