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• How to Write to AVI with OpenCV Python on Windows 10

  29 juillet 2019, par Novak

  I want to write properly formed frames of video data to an AVI.

  All attempts fail.

  What I end up with, after long efforts of debugging, are *.avi files of non-zero length in the desired directory, which will not play with any of multiple video players already installed on my system.

  Please note : High quality answers will be COMPLETE and DETAIL oriented. In particular, questions about writing video with OpenCV tend to generate drive-by responses including little more than another four-letter code to stick in fourcc. Answers which do so without also telling me at a minimum what file extension to use, what file type it will generate, and why it is expected to work over what I give above are unhelpful.

  Here are the salient details of the system :

  Operating System : Windows 10
  Language : Python 3.7, with Anaconda 3
  OpenCV : 4.1.0

  Here Is What I Have Done/Tried :

  Installed FFMPEG as per this link, restarted Anaconda, and verified ffmpeg (ffmpeg -version) from within Anaconda, with the following result :

  ffmpeg version N-94396-g47b6ca0b02 Copyright (c) 2000-2019 the FFmpeg developers
  
  built with gcc 9.1.1 (GCC) 20190716
  
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  
  libavutil      56. 32.100 / 56. 32.100
  
  libavcodec     58. 55.100 / 58. 55.100
  
  libavformat    58. 30.100 / 58. 30.100
  
  libavdevice    58.  9.100 / 58.  9.100
  
  libavfilter     7. 58.100 /  7. 58.100
  
  libswscale      5.  6.100 /  5.  6.100
  
  libswresample   3.  6.100 /  3.  6.100
  
  libpostproc    55.  6.100 / 55.  6.100

  Multiple variations on the theme of :

  import cv2
  
  fourcc = cv2.VideoWriter_fourcc(*"DIVX")
  
  vidout = cv2.VideoWriter(baseDir + "videos\\foo.avi", fourcc, 30, (530, 476))
  
  
  
  for frame in frames:
  
      <do stuff="stuff" to="to" generate="generate" foo="foo">
  
      cv2.imshow("foo", foo)
  
      vidout.write(foo)
  
  vidout.release()
  
  </do>

  Verified shape, dtype, and general viability of output data with cv2.imshow("foo", foo)

  Results : Unplayable AVI files

• "Non-monotonous DTS in output stream 0:0 This may result in incorrect timestamps in the output file." error

  1er août 2019, par petaire

  I’m trying to go from .mkv to .mp4 through ffmpeg. Normally I would use

  ffmpeg -i $1 -codec copy -strict -2 $2

  But on this particular file, I get this error, like, A LOT :

  Non-monotonous DTS in output stream 0:0; previous: 49189232, current: 49189232; changing to 49189233. This may result in incorrect timestamps in the output file.

  I guess it has something to do with the DTS :

  [mp4 @ 0x7f8b14001200] Invalid DTS: 14832 PTS: 13552 in output stream 0:0, replacing by guess
  
  [mp4 @ 0x7f8b14001200] Invalid DTS: 15472 PTS: 12272 in output stream 0:0, replacing by guess

  I would not care if the result was ok, but the sound is out of sync, and the video is "stuttering". Feels like everything is out of sync.

  I’ve tried a lot of things, including -async 1 -vsync 1 , but nothing seems to work.

  Here’s some mediainfo :

  Complete name                            : /Users/petaire/Desktop/CNEWS-2019-07-23_16-00-00h.mkv
  
  Format                                   : Matroska
  
  Format version                           : Version 2
  
  File size                                : 1.19 GiB
  
  Movie name                               : Time-2019-07-23_16:00
  
  Writing application                      : Tvheadend 4.3-1801~g7f952c2ed
  
  Writing library                          : Tvheadend Matroska muxer
  
  Original source form                     : TV
  
  Comment                                  : Time recording
  
  IsTruncated                              : Yes
  
  DATE_BROADCASTED                         : 2019-07-23 16:00:00
  
  
  
  Video
  
  ID                                       : 1
  
  Format                                   : AVC
  
  Format/Info                              : Advanced Video Codec
  
  Format profile                           : High@L4
  
  Format settings                          : CABAC / 4 Ref Frames
  
  Format settings, CABAC                   : Yes
  
  Format settings, ReFrames                : 4 frames
  
  Codec ID                                 : V_MPEG4/ISO/AVC
  
  Width                                    : 1 920 pixels
  
  Height                                   : 1 080 pixels
  
  Display aspect ratio                     : 16:9
  
  Frame rate mode                          : Constant
  
  Frame rate                               : 25.000 fps
  
  Standard                                 : Component
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 8 bits
  
  Scan type                                : MBAFF
  
  Scan type, store method                  : Interleaved fields
  
  Scan order                               : Top Field First
  
  Language                                 : English
  
  Default                                  : Yes
  
  Forced                                   : No
  
  Color range                              : Limited
  
  Color primaries                          : BT.709
  
  Transfer characteristics                 : BT.709
  
  Matrix coefficients                      : BT.709
  
  
  
  Audio
  
  ID                                       : 2
  
  Format                                   : E-AC-3
  
  Format/Info                              : Enhanced AC-3
  
  Commercial name                          : Dolby Digital Plus
  
  Codec ID                                 : A_EAC3
  
  Bit rate mode                            : Constant
  
  Bit rate                                 : 128 Kbps
  
  Channel(s)                               : 2 channels
  
  Channel layout                           : L R
  
  Sampling rate                            : 48.0 KHz
  
  Frame rate                               : 31.250 fps (1536 SPF)
  
  Compression mode                         : Lossy
  
  Delay relative to video                  : -757ms
  
  Language                                 : French
  
  Service kind                             : Complete Main
  
  Default                                  : Yes
  
  Forced                                   : No
  
  
  
  Text
  
  ID                                       : 3
  
  Format                                   : DVB Subtitle
  
  Codec ID                                 : S_DVBSUB
  
  Codec ID/Info                            : Picture based subtitle format used on DVBs
  
  Language                                 : French
  
  Default                                  : Yes
  
  Forced                                   : No

  Any idea ?

• Unrecognized option 'txt_format' in ffmpeg latest version

  26 novembre 2020, par RecklessSergio

  I am trying to convert subtitles from scenarist closed captions(scc) to webvtt(vtt)

  



  But I am getting some special characters, so going through ffmpeg documentation https://trac.ffmpeg.org/wiki/ExtractSubtitles
I got to know about the option -txt_format. But when I am using it, ffmpeg is throwing an error saying

  



  "Unrecognized option 'txt_format'.
Error splitting the argument list : Option not found"

  



  FFMPEG VERSION : 
ffmpeg version 4.1.4 Copyright (c) 2000-2019 the FFmpeg developers
 built with gcc 9.1.1 (GCC) 20190716

  



  Below is the trace level log :

  



  


  


  ffmpeg version 4.1.4 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.1.1 (GCC) 20190716
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100
Splitting the commandline.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'trace'.
Reading option '-i' ... matched as input url with argument '223163.scc'.
Reading option 'test.vtt' ... matched as output url.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option loglevel (set logging level) with argument trace.
Successfully parsed a group of options.
Parsing a group of options: input url 223163.scc.
Successfully parsed a group of options.
Opening an input file: 223163.scc.
[NULL @ 0000025d22799500] Opening '223163.scc' for reading
[file @ 0000025d2279a600] Setting default whitelist 'file,crypto'
Probing scc score:100 size:2048
[scc @ 0000025d22799500] Format scc probed with size=2048 and score=100
[scc @ 0000025d22799500] Before avformat_find_stream_info() pos: 38022 bytes read:38022 seeks:0 nb_streams:1
[scc @ 0000025d22799500] All info found
[scc @ 0000025d22799500] stream 0: start_time: -9223372036854776.000 duration: -9223372036854776.000
[scc @ 0000025d22799500] format: start_time: -9223372036854.775 duration: -9223372036854.775 bitrate=0 kb/s
[scc @ 0000025d22799500] After avformat_find_stream_info() pos: 38022 bytes read:38022 seeks:0 frames:0
Input #0, scc, from '223163.scc':
  Duration: N/A, bitrate: N/A
    Stream #0:0, 0, 1/1000: Subtitle: eia_608
Successfully opened the file.
Parsing a group of options: output url test.vtt.
Successfully parsed a group of options.
Opening an output file: test.vtt.
File 'test.vtt' already exists. Overwrite ? [y/N] y
[file @ 0000025d227d1c40] Setting default whitelist 'file,crypto'
Successfully opened the file.
Output #0, webvtt, to 'test.vtt':
  Metadata:
    encoder         : Lavf58.20.100
    Stream #0:0, 0, 1/1000: Subtitle: webvtt
    Metadata:
      encoder         : Lavc58.35.100 webvtt
Stream mapping:
  Stream #0:0 -> #0:0 (eia_608 (cc_dec) -> webvtt (native))
Press [q] to stop, [?] for help
cur_dts is invalid (this is harmless if it occurs once at the start per stream)
    Last message repeated 1 times
No more output streams to write to, finishing.
size=      19kB time=00:18:28.36 bitrate=   0.1kbits/s speed=2.26e+04x
video:0kB audio:0kB subtitle:10kB other streams:0kB global headers:0kB muxing overhead: 88.647011%
Input file #0 (223163.scc):
  Input stream #0:0 (subtitle): 411 packets read (19101 bytes); 349 frames decoded;
  Total: 411 packets (19101 bytes) demuxed
Output file #0 (test.vtt):
  Output stream #0:0 (subtitle): 349 frames encoded; 349 packets muxed (10244 bytes);
  Total: 349 packets (10244 bytes) muxed
349 frames successfully decoded, 0 decoding errors
[AVIOContext @ 0000025d22799c80] Statistics: 0 seeks, 2 writeouts
[AVIOContext @ 0000025d227a2880] Statistics: 38022 bytes read, 0 seeks