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• Ffmpeg is blocking the input video file while using GStreamer as backend with EmguCv VideoCapture [closed]

  9 octobre 2023, par Riya Sharma

  I am getting the error -
cannot access the file because it is being used by another process

  


  I am using EmguCV VideoCapture object inorder to capture input video and converting it to frames.
The frames are being saved in memory. Once all the frames are captured, i am trying to delete the input file. After that ffmpeg is being used inorder to convert the frames to the output video.

  


  When i am using reader=new VideoCapture(filepath) ; everything works fine but when i use the following -

  


  string pipeline=“filesrc location=filepath ! decodebin ! videoconvert ! appsink” ;
reader=new VideoCapture(pipeline,VideoCapture.API.Gstreamer) ;

  


  The code starts giving error -
cannot access the file because it is being used by another process

  


  Using resource monitor, got to know that ffmpeg is blocking the input file.

  


  I am using GStreamer at the input end whereas Ffmpeg at the output end. So Ffmpeg should not access the input file but still it is accessing and blocking it and therefore the input file is not getting deleted.

  


  Does anyone have any idea on how to resolve this issue ?

  


• libswscale : GBRAP input & output and GBRAP16 input support

  6 mai 2013, par Paul B Mahol

  libswscale : GBRAP input & output and GBRAP16 input support
  Signed-off-by : Paul B Mahol <onemda@gmail.com>
  

  • [DH] libavcodec/utils.c
  • [DH] libswscale/input.c
  • [DH] libswscale/output.c
  • [DH] libswscale/swscale.c
  • [DH] libswscale/swscale_internal.h
  • [DH] libswscale/swscale_unscaled.c
  • [DH] libswscale/utils.c
  • [DH] tests/ref/fate/filter-pixdesc
  • [DH] tests/ref/fate/filter-pixfmts-copy
  • [DH] tests/ref/fate/filter-pixfmts-field
  • [DH] tests/ref/fate/filter-pixfmts-hflip
  • [DH] tests/ref/fate/filter-pixfmts-il
  • [DH] tests/ref/fate/filter-pixfmts-null
  • [DH] tests/ref/fate/filter-pixfmts-pad
  • [DH] tests/ref/fate/filter-pixfmts-scale
  • [DH] tests/ref/fate/filter-pixfmts-vflip

• avformat_write_header() doesn't work when writing data to memory instead of file

  12 novembre 2020, par Mohamed Kandeel

  i want to resample a given input format from memory to memory everything is good so far.

  


  but when trying to get the output header from ffmpeg it doesn't work.

  


  here i allocate the context and pass the write_buffer function pointer so that it doesn't write to a file but instead it will call my function with the required data

  


  unsigned char * aviobuffer = (unsigned char *) av_malloc (32768);
AVIOContext * avio = avio_alloc_context (aviobuffer, 32768,1, NULL, NULL, write_buffer, NULL);

AVFormatContext* containerContext;
avformat_alloc_output_context2(&containerContext, NULL, "s16le", NULL);
containerContext->pb = avio;


  


  here is my write_buffer function

  


  std::vector<char>* data;&#xA;int write_buffer(void *opaque, uint8_t *buf, int buf_size)&#xA;{&#xA;    std::vector<char> tmp;&#xA;    tmp.assign(buf, buf &#x2B; buf_size);&#xA;    data->insert(data->end(), tmp.begin(), tmp.end());&#xA;    return buf_size;&#xA;}&#xA;</char></char>

  


  now when i call avformat_write_header() it doesn't call my write_buffer() function + it returns 0 which means success.

  


  int ret = avformat_write_header(containerContext, NULL);


  


  after that i call the appropriate functions to get the data body itself and my write_buffer() get called normally so i am now left with the data body with no header !!

  


  how can i get the output header anyways ?