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• upload video stream and audio stream on iOS

  18 juillet 2015, par ronan

  Here’s the needs : People record their video via my App and upload stream to our website, you know, like a live show.

  When they are recording, the network goes bad, then record audio instead of video.
  And when audience watch, first comes the video, in a certain time comes the audio with a static picture.

  How am I supposed to do that ? Thanks.

• Unusual results extracting VP9 pkt_size with ffprobe as compared to H.264

  26 novembre 2016, par Jeff S.

  I’m trying to graph the bitrate over time for H.264 and VP9 videos by extracting the frame size with ffprobe, but many of the VP9 videos are showing significantly lower bitrate and total size than both the file size would indicate and that ffprobe reports.

  Can someone point me in the right direction for finding the missing bytes ?

  For example :

  # The extracted values and the ffprobe values are very close for mp4
  
  Video Codec: h264
  
  Video Bitrate: 0.668869
  
  Frame Bitrate: 0.665552571931
  
  Video Size: 6381536.0
  
  Frame Total Size: 6349891
  
  
  
  # The extracted values and the ffprobe values are very different for some vp9 videos
  
  Video Codec: vp9
  
  Video Bitrate: 0.600966
  
  Frame Bitrate: 0.375144984531
  
  Video Size: 5730519.0
  
  Frame Total Size: 3577195

  Below is what I’m using for validation. Note that the sample videos do not contain audio.

  import subprocess
  
  import json
  
  
  
  def export_video_info(video_id):
  
      proc = subprocess.Popen(['ffprobe',
  
          '-v', 'quiet', '-print_format', 
  
          'json', '-show_format',
  
          '-show_streams', '-show_frames',
  
          video_id
  
          ],
  
          stdout=subprocess.PIPE,
  
      )
  
      return proc.communicate()[0]
  
  
  
  # Example video:  https://www.youtube.com/watch?v=g_OdgCrnzYo
  
  # youtube-dl --id -f 135 https://www.youtube.com/watch?v=g_OdgCrnzYo
  
  # youtube-dl --id -f 244 https://www.youtube.com/watch?v=g_OdgCrnzYo
  
  video_list = ['g_OdgCrnzYo.mp4', 'g_OdgCrnzYo.webm']
  
  
  
  '''
  
  Format for every frame: 
  
  
  
      {
  
          "media_type": "video",
  
          "key_frame": 0,
  
          "pkt_pts": 84484,
  
          "pkt_pts_time": "84.484000",
  
          "pkt_dts": 84484,
  
          "pkt_dts_time": "84.484000",
  
          "best_effort_timestamp": 84484,
  
          "best_effort_timestamp_time": "84.484000",
  
          "pkt_duration": 33,
  
          "pkt_duration_time": "0.033000",
  
          "pkt_pos": "7103361",
  
          "pkt_size": "28",
  
          "width": 854,
  
          "height": 480,
  
          "pix_fmt": "yuv420p",
  
          "sample_aspect_ratio": "1:1",
  
          "pict_type": "P",
  
          "coded_picture_number": 0,
  
          "display_picture_number": 0,
  
          "interlaced_frame": 0,
  
          "top_field_first": 0,
  
          "repeat_pict": 0
  
      },
  
  '''
  
  
  
  
  
  # NOTE: videos do not include audio
  
  for video in video_list:
  
      output = json.loads(export_video_info(video))
  
      ff_bitrate = float(output['format']['bit_rate']) / 10**6
  
      ff_duration = float(output['format']['duration'])
  
      ff_codec = output['streams'][0]['codec_name']
  
      ff_size = float(output['format']['size'])
  
      frame_size_sum = 0
  
      for val, items in enumerate(output['frames']):
  
          if output['frames'][val]['media_type'] == 'video': 
  
              frame_size_sum += int(output['frames'][val]['pkt_size'])
  
  
  
      frame_bitrate = frame_size_sum / ff_duration * 8 / 10**6
  
      print('Video Codec: {}\nVideo Bitrate: {}\nFrame Bitrate: {}\nVideo Size: {}\nFrame Total Size: {}\n\n'.format(ff_codec, ff_bitrate, frame_bitrate, ff_size, frame_size_sum))

• ffmpeg generate overlay complex filter for audio with background image

  8 janvier 2016, par user1793606

  I am experimenting with ffmpeg and would like to generate overlay complex filter for audio with background image. The code normally works, except for when adding -filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a
  it crashes. I found the example code at https://trac.ffmpeg.org/wiki/Waveform Any help is appreciated.

  Command '['c:/ffmpeg/bin\\ffmpeg.exe', '-y', '-loop', '1', '-r', '1', '-i', 'temp\\bg.png', '-i', 'test.mp3', '-filter_complex', '[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]', '-map', '[v]', '-map', '0:a', '-c:v', 'libx264', '-preset', 'ultrafast', '-tune', 'stillimage', '-crf', '15', '-pix_fmt', 'yuv420p', '-strict', 'experimental', '-c:a', 'aac', '-b:a', '256k', '-shortest', '-threads', '0', 'done/test.mp4']'

  EDIT 1 :

  I tested this with the new verson : ffmpeg -y -i input.mp3 -i background.png -filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a -c:v libx264 -c:a copy output.mp4

  It generates an output file, but only the waveform, no background included. My end goal is to generate the waveform over the background.