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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 ?

     


  


  


• Is there any library in python or can we use FFMPEG to detect the appearance of the lines pattern in video that is shown in the image attached below ? [closed]

  21 septembre 2022, par Shreyas R

  Video defect appearing frame

  


  Hi All,

  


  I am trying to find a way to detect the appearance of this lines pattern embedded in the link below.
If I get any match of this pattern in a video, I need to record that particular timestamp of the video where I got the pattern match.

  


  My idea is to take the image and compare it against the video to find for approximate match percentage. If I get it, then I record that particular timestamp within a .txt file.

  


  Is there any better way to achieve this ?
I think we can use Python or FFMPEG video filters to get a solution for this.

  


  It would really help if anyone can support with a solution. Thanks

  


  Update :
I got a reference where they have proposed a solution similar to my concern.

  


  https://aws.amazon.com/blogs/media/metfc-automatically-compare-two-videos-to-find-common-content/

  


  So we can try to achieve some output from this solution.