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• ffmpeg running on windows with java

  24 décembre 2013, par Karn_way

  I have simple test class as

  public static void main(String[] args) throws IOException {
  
  
  
           String[] line = {"ffmpeg -i D:\\hadoop-video\\testVideo\\xyz.mp4 %d.png"};
  
           Runtime.getRuntime().exec(line);
  
  
  
      }

  when I try to run this I am getting

  Exception in thread "main" java.io.IOException: Cannot run program "ffmpeg -i D:/hadoop-video/testVideo/xyz.mp4 %d.png": CreateProcess error=2, The system cannot find the file specified
  
      at java.lang.ProcessBuilder.start(Unknown Source)
  
      at java.lang.Runtime.exec(Unknown Source)
  
      at java.lang.Runtime.exec(Unknown Source)
  
      at ImageTest.main(ImageTest.java:13)
  
  Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified

  however file is present on my windows7 machine with location

  D:\hadoop-video\testVideo\xyz.mp4

  i tried removing .mp4 and then run also not working . please suggest what might be wrong

• Saving highest quality video from video-capture card

  23 décembre 2013, par DusteD

  I have a machine with 2x3 3ghz dual-core xeon and 4x10krpm scsi 320 disks in raid0.
  The capture card is an osprey 560 64 bit pci card.
  Operating system is currently Windows Server 2003.

  The video-stream that I can open with VLC using direct show is rather nice quality.
  However, trying to save this video-stream without loss of quality has proven quite difficult,
  using the h264 codec I am able to achieve a satisfying quality, however, all 4 cores jump to 100% load after a few second and then it start dropping frames, the machine is not powerful enough for realtime encoding. I've not been able to achieve satisfying mpeg1 or 4 quality, no matter which bitrate I set..

  Thing is, the disks in this machine are pretty fast even by todays standard, and they are bored.. I don't care about disk-usage, I want quality.
  I have searched in vain for a way to pump that beautiful videostream that I see in VLC onto the disk for later encoding, I reckon the disks would be fast enough, or maybe something which would apply a light compression, enough that the disks can keep up, but not so much as to loose visible quality.

  I have tried FFMPEG as it seems capable of streaming a yuv4 stream down to the disk, but ofcause FFMPEG is unable to open the dshow device ( same error as this guy Ffmpeg streaming from capturing device Osprey 450e fails )

  Please recommend a capable and (preferably) software which can do this.

• Why do I get different codecs on Windows and Linux with same code ?

  27 janvier 2016, par user3277340

  I am using the API version of FFMPEG to generate a MP4 file from a series of images. I specify the output by calling

  AVFormatContext *oc = NULL ;
  avformat_alloc_output_context2 (&oc,NULL,"mp4",NULL) ;

  Running the exact same code on Windows and Linux I get different codecs assigned. On Windows, the value of oc->oformat->video_code is AV_CODEC_ID_H264 (28), but on Linux I get AV_CODEC_ID_MPEG4.

  I tracked this down because on Windows my calls to avcodec_encode_video2(.,.,.,&got_packet) were always returning got_packet=0 so I never called av_interleaved_write_frame. I added a NULL AVFrame at the end to flush the video. But it was very small and did not contain the images I expected to see there.

  But on Linux everything worked just fine. So I went ahead and manually changed the value of oc->oformat->video_code and I got the expected results.

  My questions :

  1) Why do I get different codec types on different platforms with the same code ? Is there a parameter I need to set to force MPEG4 ?

  2) Is it "legal" to change this parameter after the call to avformat_alloc_output_context2 ? My concern is that "oc" has been properly initialized and, with the change, something may be inconsistent.

  3) Is there a way to force the MPEG4 codec on any machine ?

  Thanks.