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• librosa can't load wav file in aws lambda docker

  30 novembre 2022, par Luka Savic

  I have an AWS Lambda function created using Docker.
I have librosa installed, ffmpeg installed using the solution from this question : install ffmpeg on amazon ecr linux python

  


  I checked in a Lambda function with os.system("ffmpeg -version") and I managed to get valid output, stating different versions and parts of ffmpeg.

  


  Problem is that when I do librosa.load(wav_file) it gives the following error :

  


  /your/path/.venv/lib/python3.9/site-packages/librosa/util/decorators.py:88: UserWarning: PySoundFile failed. Trying audioread instead.
  return f(*args, **kwargs) 


  


  From what I've read, librosa should natively support .wav files, even without ffmpeg, and even though I have ffmpeg installed, it doesn't work.

  


  One more information, .wav file was downloaded, player, and loaded with librosa on my local PC without any problems. I tried also on different wav and mp3 files, and the problems were still there.

  


• Why does ffmpeg hang indefinitely when composing videos ?

  11 octobre 2022, par Brendan Hill

  I am executing ffmpeg commands in a Java microservice (which runs dockerised in kubernetes in a temporary pod created by KEDA from an Amazon SQS queue... but unlikely to be relevant).

  


  About 30% of the time, the ffmpeg process hangs indefinitely :

  


  
/usr/local/bin/ffmpeg 
     -i /tmp/transcode-3b928f5f-3cd9-4cd6-9175-b7c1621aa7ce13592236077853079159/person1.mkv 
     -i /tmp/transcode-3b928f5f-3cd9-4cd6-9175-b7c1621aa7ce13592236077853079159/person2.mkv
     -filter_complex [0:v][1:v]hstack=inputs=2[v];[0:a]aresample=async=1000[0sync];[1:a]aresample=async=1000[1sync];[0sync][1sync]amix[a] 
     -map [v] 
     -map [a] 
     -c:v libx264 
     -crf 18 
     -ac 2 
     -vsync 1 
     -r 25 
     -shortest /tmp/transcode-3b928f5f-3cd9-4cd6-9175-b7c1621aa7ce13592236077853079159/composed.mp4



  


  This causes the Java code to wait indefinitely :

  


  
        Process proc = Runtime.getRuntime().exec(cmd);

        StreamConsumer outConsumer = new StreamConsumer(proc.getInputStream(), stdout);
        StreamConsumer errConsumer = new StreamConsumer(proc.getErrorStream(), stderr);

        // execute data read/write in separate threads
        outExecutor.submit(outConsumer);
        errorExecutor.submit(errConsumer);

        proc.waitFor() // Hangs indefinitely, with ~30% probability



  


  It is not specifically about the video files because they generally work on retry (with similar 30% failure probability so sometimes several retries are necessary). Of course, since it hangs indefinitely instead of exiting with failure, it has to wait hours before we risk another retry.

  


  


  1. Why is ffmpeg hanging indefinitely and how to fix ?

     


  


  2. Can I get ffmpeg to fail early instead of hanging indefinitely (so I can trigger retry immediately) ?

     


  


  3. I see many questions and posts about ffmpeg hanging indefinitely. Is ffmpeg inherently unstable ?

     


  


  


• swscale/aarch64 : vscale optimization

  13 août 2022, par Swinney, Jonathan

  swscale/aarch64 : vscale optimization
  Use scalar times vector multiply accumlate instructions instead of
  
  vector times vector to remove the need for replicating load instructions
  
  which are slightly slower.
  On AWS c7g (Graviton 3, Neoverse V1) instances :
  
  yuv2yuvX_8_0_512_accurate_neon :  1144.8  987.4
  
  yuv2yuvX_16_0_512_accurate_neon : 2080.5 1869.4
  Signed-off-by : Jonathan Swinney <jswinney@amazon.com>
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libswscale/aarch64/output.S