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• How to use FFmpeg(v 4.0) HwAccell in Android

  21 novembre 2018, par 심상원

  I’m making an app that uses FFmpeg on Android to show the screen.

  I have a few questions to ask you.

  std::vector <avhwdevicetype> GetSupportHwDeviceType ()
  
  {
  
      unsigned int idx {};
  
      std::vector <avhwdevicetype> hwDevTypes;
  
  
  
      AVHWDeviceType hwDevType = AVHWDeviceType::AV_HWDEVICE_TYPE_NONE;
  
      while ((hwDevType = av_hwdevice_iterate_types (hwDevType)) ! = AVHWDeviceType::AV_HWDEVICE_TYPE_NONE)
  
      {
  
          __android_log_print (ANDROID_LOG_DEBUG, __func__, "[Index% d]", idx ++);
  
          __android_log_print (ANDROID_LOG_DEBUG, __func__,
  
                          "[Support Device Name% s]", av_hwdevice_get_type_name (hwDevType));
  
  
  
          hwDevTypes.push_back (hwDevType);
  
      }
  
  
  
      return hwDevTypes;
  
  }
  
  </avhwdevicetype></avhwdevicetype>

  I would like to use hardware acceleration with the above function, and as a result I could not find any type.

  At https://trac.ffmpeg.org/wiki/HWAccelIntro, it says that Android can use MediaCodec. Why can not I retrieve any type from Android NDK with GetSupportHwDeviceType () ?

  The Configure argument used while building FFmpeg for Android.

  --disable-asm
  
  --enable-cross-comile
  
  --disable-static
  
  --disable-programs
  
  --disable-doc
  
  --enable-shared
  
  --enable-protocol=file
  
  --enable-pic
  
  --enable-small
  
  --enable-mediacodec
  
  --enable-jni
  
  --enable-decoder=h264_mediacodec
  
  --enable-opengl
  
  
  
  /* The argument was not supported by ./configure --list-hwaccel in FFmpeg v4.0.3. */
  
  
  
  --enable-hwaccel=h264_mediacodec 

• FFmpeg output video file much smaller than uncompressed input audio file, using option to preserve original audio quality

  17 mars 2021, par Jan

  I attempt to create a video slideshow from a number of image files and an audio file in 2 steps :

  


  

  1. Create a temporary video file from a sequence of image files

  


  2. Add an audio file to the temporary video file with a delay of 5 seconds

  


  


  The audio file is an uncompressed stereo wav file, encoded with a sample rate of 44100 Hz and a bit depth of 32 bits, with a size of 40.1 MB. To preserve the lossless quality of the input audio file I use the option -c:a aac -b:a 192k as per Slideshow Wiki. However, the final output video file has a size of only 4.49 MB.

  


  How can the output video file be about 10 times smaller than the input audio file and still preserve the original lossless quality ?

  


  My code :

  


  ffmpeg -f concat -i slide-sequence.txt -c:v libx264 -r 30 -filter_complex format=yuv420p temp.mp4
ffmpeg -i temp.mp4 -i audio.wav -af "adelay=5000|5000" -c:v copy -c:a aac -b:a 192k out.mp4


  


• how to have live video streaming using ffmpeg command or using tcl 8.0 script on windows 10 platform [duplicate]

  16 novembre 2017, par M. D. P

  This question is an exact duplicate of :

  • How to stream live-video display from a webcam using FFMPEG command on tcl version 8.0 and windows 7 ?
    
    1 answer
    

  I am able to capture the video and image by using ffmpeg in tcl script, but I want to have live video streaming for my multiple webcams for tcl version 8.0 on windows 10.

  I tryed :

  ffmpeg -f vfwcap -r 25 -i 0 sample.avi

  for video capturing, it works

  ffmpeg -f vfwcap -r 25 -i 0 

  and I tried this for live video streaming by it didn’t http://wiki.tcl.tk/40194
  So what will be the right command for live video streaming.

  exec [list ffmpeg -f dshow -t 00:00:10 -i "video=Integrated Webcam" -b 5000k -s 1280x720 c :/test/sample-a.avi] &

  also tried with this, still not working