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• Taking care of silent priming frames converting mp4 to ts ?

  13 février 2019, par keepitterron

  videoOutputSettings = [
  
    AVVideoCodecKey: AVVideoCodecH264,
  
    AVVideoWidthKey: width,
  
    AVVideoHeightKey: height,
  
    AVVideoCompressionPropertiesKey: [
  
      AVVideoAverageBitRateKey: avgBitRate,
  
      AVVideoExpectedSourceFrameRateKey: fps,
  
      AVVideoProfileLevelKey: AVVideoProfileLevelH264BaselineAutoLevel
  
    ]
  
  ]
  
  audioOutputSettings = [
  
    AVFormatIDKey: kAudioFormatMPEG4AAC,
  
    AVSampleRateKey: 44100,
  
    AVNumberOfChannelsKey: 2
  
  ]

  I record a video + audio with AVCaptureSession (screen, camera and mic in OSX) and i encode it with AVAssetWriter (AVFileType.mp4), swapping the writers every 6 seconds.
  Every time a new part is written, a nodeJS app will be notified and using ffmpeg will convert it to ts with

  ffmpeg -y -i generatedFile.mp4 -c copy -copyts -muxdelay 0 -muxpreload 0 outputFile.ts

  I’ll manually write a m3u8 looking like :

  #EXTM3U
  
  #EXT-X-VERSION:3
  
  #EXT-X-TARGETDURATION:7
  
  #EXT-X-MEDIA-SEQUENCE:0
  
  #EXT-X-PLAYLIST-TYPE:VOD
  
  #EXTINF:6.140227,
  
  11214532343c4cae953d45e94a1660ea-0.ts
  
  #EXTINF:6.284218,
  
  11214532343c4cae953d45e94a1660ea-1.ts
  
  #EXTINF:6.099999999999998,
  
  11214532343c4cae953d45e94a1660ea-2.ts
  
  #EXTINF:6.133333,
  
  11214532343c4cae953d45e94a1660ea-3.ts
  
  #EXTINF:6.133333,
  
  11214532343c4cae953d45e94a1660ea-4.ts
  
  #EXTINF:6.100000000000001,
  
  11214532343c4cae953d45e94a1660ea-5.ts
  
  #EXTINF:6.133333,
  
  11214532343c4cae953d45e94a1660ea-6.ts
  
  #EXTINF:6.199999999999996,
  
  11214532343c4cae953d45e94a1660ea-7.ts
  
  #EXTINF:6.0666670000000025,
  
  11214532343c4cae953d45e94a1660ea-8.ts
  
  #EXT-X-ENDLIST

  The issue is : I have audio gaps between parts and I believe is AAC’s priming frames not being handled correctly.
  Am I correct in assuming so ?

  example file

  ❯ afinfo 11.mp4
  
  File:           11.mp4
  
  File type ID:   mp4f
  
  Num Tracks:     1
  
  ----
  
  Data format:     2 ch,  44100 Hz, 'aac ' (0x00000000) 0 bits/channel, 0 bytes/packet, 1024 frames/packet, 0 bytes/frame
  
                  no channel layout.
  
  estimated duration: 6.128617 sec
  
  audio bytes: 87558
  
  audio packets: 266
  
  bit rate: 113407 bits per second
  
  packet size upper bound: 401
  
  maximum packet size: 401
  
  audio data file offset: 577163
  
  optimized
  
  audio 270272 valid frames + 2112 priming + 0 remainder = 272384
  
  format list:
  
  [ 0] format:      2 ch,  44100 Hz, 'aac ' (0x00000000) 0 bits/channel, 0 bytes/packet, 1024 frames/packet, 0 bytes/frame
  
  Channel layout: Stereo (L R)
  
  ----

  example file

  ❯ ffprobe -v error -show_format -show_streams 1.mp4
  
  [STREAM]
  
  index=0
  
  codec_name=h264
  
  codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
  
  profile=Baseline
  
  codec_type=video
  
  codec_time_base=1/60
  
  codec_tag_string=avc1
  
  codec_tag=0x31637661
  
  width=1920
  
  height=1080
  
  coded_width=1920
  
  coded_height=1088
  
  has_b_frames=0
  
  sample_aspect_ratio=1:1
  
  display_aspect_ratio=16:9
  
  pix_fmt=yuv420p
  
  level=40
  
  color_range=tv
  
  color_space=bt709
  
  color_transfer=bt709
  
  color_primaries=bt709
  
  chroma_location=bottom
  
  field_order=unknown
  
  timecode=N/A
  
  refs=1
  
  is_avc=true
  
  nal_length_size=4
  
  id=N/A
  
  r_frame_rate=30/1
  
  avg_frame_rate=30/1
  
  time_base=1/600
  
  start_pts=3600
  
  start_time=6.000000
  
  duration_ts=7260
  
  duration=12.100000
  
  bit_rate=4227137
  
  max_bit_rate=N/A
  
  bits_per_raw_sample=8
  
  nb_frames=183
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  DISPOSITION:default=1
  
  DISPOSITION:dub=0
  
  DISPOSITION:original=0
  
  DISPOSITION:comment=0
  
  DISPOSITION:lyrics=0
  
  DISPOSITION:karaoke=0
  
  DISPOSITION:forced=0
  
  DISPOSITION:hearing_impaired=0
  
  DISPOSITION:visual_impaired=0
  
  DISPOSITION:clean_effects=0
  
  DISPOSITION:attached_pic=0
  
  DISPOSITION:timed_thumbnails=0
  
  TAG:creation_time=2019-02-13T13:21:51.000000Z
  
  TAG:language=und
  
  TAG:handler_name=Core Media Video
  
  [/STREAM]
  
  [STREAM]
  
  index=1
  
  codec_name=aac
  
  codec_long_name=AAC (Advanced Audio Coding)
  
  profile=LC
  
  codec_type=audio
  
  codec_time_base=1/44100
  
  codec_tag_string=mp4a
  
  codec_tag=0x6134706d
  
  sample_fmt=fltp
  
  sample_rate=44100
  
  channels=2
  
  channel_layout=stereo
  
  bits_per_sample=0
  
  id=N/A
  
  r_frame_rate=0/0
  
  avg_frame_rate=0/0
  
  time_base=1/44100
  
  start_pts=272991
  
  start_time=6.190272
  
  duration_ts=545352
  
  duration=12.366259
  
  bit_rate=115688
  
  max_bit_rate=128000
  
  bits_per_raw_sample=N/A
  
  nb_frames=269
  
  nb_read_frames=N/A
  
  nb_read_packets=N/A
  
  DISPOSITION:default=1
  
  DISPOSITION:dub=0
  
  DISPOSITION:original=0
  
  DISPOSITION:comment=0
  
  DISPOSITION:lyrics=0
  
  DISPOSITION:karaoke=0
  
  DISPOSITION:forced=0
  
  DISPOSITION:hearing_impaired=0
  
  DISPOSITION:visual_impaired=0
  
  DISPOSITION:clean_effects=0
  
  DISPOSITION:attached_pic=0
  
  DISPOSITION:timed_thumbnails=0
  
  TAG:creation_time=2019-02-13T13:21:51.000000Z
  
  TAG:language=und
  
  TAG:handler_name=Core Media Audio
  
  [/STREAM]
  
  [FORMAT]
  
  filename=1.mp4
  
  nb_streams=2
  
  nb_programs=0
  
  format_name=mov,mp4,m4a,3gp,3g2,mj2
  
  format_long_name=QuickTime / MOV
  
  start_time=6.000000
  
  duration=12.366259
  
  size=3317034
  
  bit_rate=2145860
  
  probe_score=100
  
  TAG:major_brand=mp42
  
  TAG:minor_version=1
  
  TAG:compatible_brands=mp41mp42isom
  
  TAG:creation_time=2019-02-13T13:21:51.000000Z
  
  [/FORMAT]

  Is there a way I can generate ts files with the encoder delay being taken care of ?

• How do I draw a line over a video whose width equals the current timeframe using FFMPEG

  19 août 2019, par Martin Mbae

  I am trying to draw a line across a video to show the progress of the video.

  Using FFMPEG I am able to draw a line using this code

  ffmpeg -i video.mp4 -vf drawbox=w=10:h=10:color=pink:t=fill output.mp4

  I, however want to alter the width of the line to be equal to "Total number of frames divided by the current frame"

  I am using this code

  ffmpeg -i video.mp4 -vf drawbox=w="%{frame_num/120}":h=10:color=pink:t=fill output.mp4

  which is giving me this error

  [Eval @ 00000072037fe4f0] Undefined constant or missing ’(’ in ’%frame_num/120’

  I have also tried the code below which is also not giving me what I want.

  ffmpeg -i video.mp4 -vf drawbox=w='text=%{frame_num/120}':h=10:color=pink:t=fill output.mp4

  How do I go about this. Specifically how to set the width of the box to be equal to the number of the current frame

• split the video into five chunks using ffmpeg and batch script

  21 janvier 2019, par RJFF

  I want to split videos into five chunks using ffmpeg

  the first chunk represents 20% of the whole video
  the second chunk represents 40% of the whole video
  the third chunk represents 60% of the whole video
  the fourth chunk represents 80% of the whole video

  the fifth chunk represents 100% of the whole video

  I write the algorithm but I do not know how to write the batch code :
  1. find the duration of the video
  2. store the duration in variable
  3. divided the duration by 5
  4. split the video

  I want a batch script that takes the duration of the video then store the value of duration in the variable

  this is how I can take the duration of the video

  ffmpeg -i C:\video-splitter-master\1.avi 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }'

  but how I can store the duration value in the variable ?

  can you please help me ?