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• How do I run ffmpeg v360 filter on a stream with limited memory ?

  21 février 2024, par Dmitry Filippov

  I am currently using ffmpeg python in a microservice for changing a projection of a VR video in S3 bucker. Ideally I would like to use as little memory as possible, reading a video file from s3 as a stream, transcoding it and uploading back into a separate file all in-memory.

  


  However, when I run this code with large videos (above 10GB), the ffmpeg process gets terminated with no exception and boto3 uploads a 0B "file" to s3. When I run this with a small (100MB) video or on my local machine with 16GB RAM, the upload finishes up fine.

  


  Code :

  


    with (
    ffmpeg
    .input(input_url)
    .filter("v360", inputProjection, outputProjection, in_stereo=inputStereo, out_stereo=outputStereo)
    .output('pipe:', format=outputFormat)
    .run_async(pipe_stdout=True)
  ).stdout as dataStream:
     client.upload_fileobj(dataStream, aws_s3_bucket, outputFile)


  


  I expect the ffmpeg to apply the filter to a video as a stream only holding a small section in memory at a time, but instead it seems to try to download the entire video into the local memory before applying the filter (when the script fails, stdout contains either no data or only the metadata of the video)

  


  I cannot support the full download as I am planning to use the script on 100GB+ videos and it needs to run as a microservice in a kubernetes cluster.

  


• How to draw a waveform from an RTSP audio using ffmpeg and Python

  9 mars 2023, par S Andrew

  I have a Hikvision camera. Using ffmpeg, I can extract the audio from it and save it in wav file using below code :

  


  import os
os.system("ffmpeg -i rtsp://admin:password@192.168.0.27:554/Streaming/Channels/101/ -q:a 0 -map a -t 10 file.wav")


  


  It creates file.wav file and when played I can hear the audio recorded from camera. Now I am planning to draw the waveform of these audio's. For this I have below code :

  


  os.system("ffmpeg -i rtsp://admin:password@192.168.0.27:554/Streaming/Channels/101/ -filter_complex showwavespic -frames:v 1 output.png")


  


  and below is the output I get after pressing q

  


  [q] command received. Exiting.

Finishing stream 0:0 without any data written to it.
Output #0, image2, to 'output.png':
  Metadata:
    title           : Media Presentation
    encoder         : Lavf59.26.100
  Stream #0:0: Video: png, rgba, 600x240 [SAR 1:1 DAR 5:2], q=2-31, 200 kb/s, 1 fps, 1 tbn
    Metadata:
      encoder         : Lavc59.36.100 png
frame=    0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x    
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)


  


  and there is no file generated. I tried the above code with and mp3 file and it generated the output.png with waveform. How can I resolve the issue ?

  


• avformat/mov : set correct error code in mov_read_custom

  27 novembre 2017, par Pan Bian

  avformat/mov : set correct error code in mov_read_custom
  In function mov_read_custom(), it returns 0 on the path that av_malloc()
  
  returns a NULL pointer. 0 indicates success. An error code should be
  
  assigned to ret.
  Signed-off-by : Pan Bian <bianpan2016@163.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/mov.c