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• Streaming without Content-Length in response

  21 décembre 2023, par kain

  I'm using Node.js, Express (and connect), and fluent-ffmpeg.

  



  We want to stream audio files that are stored on Amazon S3 through http.

  



  We have all working, except that we would like to add a feature, the on-the-fly conversion of the stream through ffmpeg.

  



  This is working well, the problem is that some browsers checks in advance before actually getting the file.

  



  Incoming requests containing the Range header, for which we reply with a 206 with all the info from S3, have a fundamental problem : we need to know in advance the content-length of the file.

  



  We don't know that since it is going through ffmpeg.

  



  One solution might be to write out the resulting content-length directly on S3 when storing the file (in a special header), but this means we have to go through the pain of having queues to encode after upload just to know the size for future requests.
It also means that if we change compressor or preset we have to go through all this over again, so it is not a viable solution.

  



  We also noticed big differencies in the way Chrome and Safari request the audio tag src, but this may be discussion for another topic.

  



  Fact is that without a proper content-length header in response everything seems to break or browsers goes in an infinite loop or restart the stream at pleasure.

  



  Ideas ?

  


• ffmpeg extract multiple frames from single input causing SIGSEGV in node.js child_process on lambda env

  11 octobre 2023, par Andrew Still

  I'm trying to dynamically extract multiple different frames from single video input. So the command I'm calling looking like this

  


  ffmpeg -loglevel debug -hide_banner -t 13.269541 -y -ss 0 -i "input-s3-url" -ss 13.269541 -i "same-input-s3-url" -map 0:v -vframes 1 /tmp/ca4cd7a3159743938c5362c171ea2cae.0.png -map 1:v -vframes 1 /tmp/ca4cd7a3159743938c5362c171ea2cae.13.269541.png


  


  It works and everything is good, until I deploy it to lambda. Even though I'm using 10gb of RAM it still failing with error. Locally it works like a charm but not on lambda. I'm not sure what the problem here but i'm regularly (not always) getting SIGSEGV

  


  at ChildProcess.exithandler (node:child_process:402:12)
at ChildProcess.emit (node:events:513:28) 
at ChildProcess.emit (node:domain:489:12)
at maybeClose (node:internal/child_process: 1100:16)
at Process.ChildProcess._handle.onexit (node:internal/child_process:304:5) 
{
code: null, 
killed: false, 
signal: 'SIGSEGV'
cmd: '/opt/bin/ffmpeg -loglevel error -hide_banner -t 131.805393 -y -ss 0 -i "https: //


  


  Double-checked memory usage and it's doesn't look like a reason, but I'm not sure how correct this number

  


  Memory size : 10240 MB Max Memory used : 140 MB

  


  I'm think maybe it's because it's making requests for each input, at least that's what I saw in debug mode, but still have no idea what's the problem here, would appreciate any suggestions/optimizations/help. Thanks

  


  ffmpeg added on lambda using this layer - https://serverlessrepo.aws.amazon.com/applications/us-east-1/145266761615/ffmpeg-lambda-layer

  


• ffmpeg extract multiple frames from single input

  10 octobre 2023, par Andrew Still

  I'm trying to dynamically extract multiple different frames from single video input. So the command I'm calling looking like this

  


  ffmpeg -loglevel debug -hide_banner -t 13.269541 -y -ss 0 -i "input-s3-url" -ss 13.269541 -i "same-input-s3-url" -map 0:v -vframes 1 /tmp/ca4cd7a3159743938c5362c171ea2cae.0.png -map 1:v -vframes 1 /tmp/ca4cd7a3159743938c5362c171ea2cae.13.269541.png


  


  It works and everything is good, until I deploy it to lambda. Even though I'm using 10gb of RAM it still failing with error. Locally it works like a charm but not on lambda. I'm not sure what the problem here but i'm regularly (not always) getting SIGSEGV

  


  

  


  Double-checked memory usage and it's doesn't look like a reason, but I'm not sure how correct this number

  


  

  


  I'm think maybe it's because it's making requests for each input, at least that's what I saw in debug mode, but still have no idea what's the problem here, would appreciate any suggestions/optimizations/help. Thanks

  


  ffmpeg added on lambda using this layer - https://serverlessrepo.aws.amazon.com/applications/us-east-1/145266761615/ffmpeg-lambda-layer