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• FFmpeg stream extraction modifies subtitles [closed]

  21 mai 2024, par user18812922

  I have a video with the following ffprobe output :

  


  Input #0, matroska,webm, from 'video.mkv':
  Metadata:
    title           : Video - 01
    creation_time   : 2021-07-14T02:49:59.000000Z
    ENCODER         : Lavf58.29.100
  Duration: 00:22:57.28, start: 0.000000, bitrate: 392 kb/s
  Chapters:
    Chapter #0:0: start 0.000000, end 86.169000
      Metadata:
        title           : Opening
    Chapter #0:1: start 86.169000, end 641.266000
      Metadata:
        title           : Part A
    Chapter #0:2: start 641.266000, end 651.359000
      Metadata:
        title           : Eyecatch
    Chapter #0:3: start 651.359000, end 1286.160000
      Metadata:
        title           : Part B
    Chapter #0:4: start 1286.160000, end 1356.355000
      Metadata:
        title           : Ending
    Chapter #0:5: start 1356.355000, end 1376.876000
      Metadata:
        title           : Preview
  Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt709), 854x480 [SAR 1280:1281 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
      Metadata:
        DURATION        : 00:22:56.959000000
  Stream #0:1(eng): Audio: vorbis, 48000 Hz, stereo, fltp (default)
      Metadata:
        title           : English [FLAC 2.0]
        DURATION        : 00:22:57.278000000
  Stream #0:2(jpn): Audio: vorbis, 48000 Hz, stereo, fltp
      Metadata:
        title           : Japanese [FLAC 2.0]
        DURATION        : 00:22:57.276000000
  Stream #0:3(eng): Subtitle: ass (ssa)
      Metadata:
        title           : Signs and Songs [FMA1394/Redc4t]
        DURATION        : 00:22:51.090000000
  Stream #0:4(eng): Subtitle: ass (ssa)
      Metadata:
        title           : English [FMA1394/Redc4t]
        DURATION        : 00:22:51.090000000
  Stream #0:5(eng): Subtitle: hdmv_pgs_subtitle (pgssub), 1920x1080
      Metadata:
        title           : Full English Retail
        DURATION        : 00:22:51.120000000
  Stream #0:6: Attachment: ttf
      Metadata:
        filename        : 8bitoperator.ttf
        mimetype        : application/x-truetype-font
  Stream #0:7: Attachment: ttf
      Metadata:
        filename        : Cabin-Bold.ttf
        mimetype        : application/x-truetype-font
  Stream #0:8: Attachment: ttf
      Metadata:
        filename        : calibrib.ttf
        mimetype        : application/x-truetype-font
  Stream #0:9: Attachment: ttf
      Metadata:
        filename        : daniel_0.ttf
        mimetype        : application/x-truetype-font
  Stream #0:10: Attachment: ttf
      Metadata:
        filename        : DEATH_FONT.TTF
        mimetype        : application/x-truetype-font
  Stream #0:11: Attachment: ttf
      Metadata:
        filename        : Dominican.ttf
        mimetype        : application/x-truetype-font
  Stream #0:12: Attachment: ttf
      Metadata:
        filename        : gishabd.ttf
        mimetype        : application/x-truetype-font
  Stream #0:13: Attachment: ttf
      Metadata:
        filename        : PATRICK_0.TTF
        mimetype        : application/x-truetype-font
  Stream #0:14: Attachment: ttf
      Metadata:
        filename        : Qlassik-Medium.ttf
        mimetype        : application/x-truetype-font
Unsupported codec with id 98304 for input stream 6
Unsupported codec with id 98304 for input stream 7
Unsupported codec with id 98304 for input stream 8
Unsupported codec with id 98304 for input stream 9
Unsupported codec with id 98304 for input stream 10
Unsupported codec with id 98304 for input stream 11
Unsupported codec with id 98304 for input stream 12
Unsupported codec with id 98304 for input stream 13
Unsupported codec with id 98304 for input stream 14


  


  I am trying to extract the subtitles, edit them and reattach them to the video.
(I need my program to do that so I don't want to use other software)

  


  Command 1

  


  ffmpeg -i video.mkv -map 0:3 -c:s ssa subs.ass
ffmpeg -i video.mkv -i subs.ass -map 0 -map -0:s -map 1 -c copy out.mkv


  


  Command 2

  


  ffmpeg -i video.mkv -map 0:3 subs.ass
ffmpeg -i video.mkv -i subs.ass -map 0 -map -0:s -map 1 -c copy out.mkv


  


  Command 3

  


  ffmpeg -i video.mkv -map 0:3 subs.srt
ffmpeg -i video.mkv -i subs.srt -map 0 -map -0:s -map 1 -c copy out.mkv


  


  Command 4

  


  ffmpeg -i video.mkv -map 0:3 subs.srt
ffmpeg -i subs.srt subs.ass
ffmpeg -i video.mkv -i subs.ass -map 0 -map -0:s -map 1 -c copy out.mkv


  


  Command 5

  


  ffmpeg -i video.mkv -map 0:3 subs.ass
ffmpeg -i subs.ass subs.srt
ffmpeg -i video.mkv -i subs.srt -map 0 -map -0:s -map 1 -c copy out.mkv


  


  The problem

  


  After extraction the subtitles seem to be really quick, meaning they are displayed and disappear really quickly.

  


  For example the first subtitle is as follows in srt :

  


  1&#xA;00:00:03,100 --> 00:00:03,560&#xA;<font face="Dominican" size="77" color="#f7f7f7">Within the spreading darkness</font>&#xA;

  


  Now, in srt it also has wrong size but I assume that's because of the conversion from ass to srt.

  


  If I reattach the subtitle file in the video and open it, it is displayed and disappears way too fast and it doesn't match the original subtitles in the video.

  


  (ie, the original video subtitles are showing for at least a second)

  


  Expected behaviour

  


  The subtitles should be displayed for the same duration as the original subtitles.

  


  NOTE

  


  It's my first question for ffmpeg related issues so feel free to ask me for anything else you may need.

  


  UPDATE 1

  


  I realized that the subtitles were ok for the timings as they had the same line multiple times, so the problem for not playing is something else.

  


  Example of the file

  


  1&#xA;00:00:03,100 --> 00:00:03,560&#xA;<font face="Dominican" size="77" color="#f7f7f7">Within the spreading darkness</font>&#xA;&#xA;2&#xA;00:00:03,560 --> 00:00:04,650&#xA;<font face="Dominican" size="77" color="#f7f7f7">Within the spreading darkness</font>&#xA;&#xA;3&#xA;00:00:04,650 --> 00:00:05,100&#xA;<font face="Dominican" size="77" color="#f7f7f7">Within the spreading darkness</font>&#xA;

  


  So the problem is that VLC doesn't show more than the first subtitle.

  


  The strange thing is when I use the below command

  


  ffmpeg -i video.mkv -i subs.srt -map 0 -map -0:s -map 1 -c copy -c:s subrip out.mkv


  


  Then more lines of the subtitle (but not all) play.

  


  It stops at the 17th line.

  


  I believe that's an encoder's problem ? but I really don't know.

  


  Also what I noticed is that VLC stops the subtitles but Windows Media Player (Windows 11 version) display the subtitles correctly even after the 17th line.

  


  BUT, if I add subtitles from another video they are played correctly in both VLC and Windows Media Player.

  


  Update 2
As @Gyan said in his answer I should use the following command

  


  ffmpeg -i video.mkv -map 0:3 -c:s copy subs.ass


  


  But then if I attach the subs again with

  


  ffmpeg -i video.mkv -i subs.ass -map 0 -map -0:s -map 1 -c copy -c:s ass out.mkv


  


  The subtitles show up to 17th line in both VLC and Windows Media Player.

  


  or

  


  ffmpeg -i video.mkv -i .\subs.ass -map 0 -map -0:s -map 1 -c copy out.mkv


  


  The subtitles do not show up at all. (Not even in Windows Media Player)

  


• Reject multiple headers of the same type.

  7 janvier 2015, par Tim Terriberry

  Reject multiple headers of the same type.
  A common application pattern is to call vorbis_synthesis_headerin()
  
   and count how many times it succeeds.
  
  If you feed it multiple valid comment headers, they will all
  
   succeed, meaning you can be fooled into think you have a valid
  
   Vorbis file despite never seeing a setup header.
  
  This patch makes libvorbis reject multiple headers of the same type,
  
   preventing this from occurring.
  git-svn-id : http://svn.xiph.org/trunk/vorbis@19426 0101bb08-14d6-0310-b084-bc0e0c8e3800
  

  • [DH] lib/info.c

• Slicing video on several short clips of different lengths in one go

  1er décembre 2019, par Igniter

  I’ve got time codes using which I want to slice a short MP4 video (average length 5-7 minutes)

  [ 0, 15, 35, 52, 142, 215, ...] // time codes in seconds

  Usually there are 5-7 time codes meaning that I need to create 5-7 clips out of my initial video
  The fist clip is from start to 15 sec, the second one is from 15 sec to 35 sec, 35-52, etc.

  It’s trivial operation in Bash but I’m using ffmpeg on NodeJS and I’d like to do it without iteration in one go

  // Slicing a single clip
  
  ffmpeg -i input.mp4 -ss 0 -to 15 -c copy clip-01.mp4
  
  
  
  // Same command in NodeJS
  
  ffmpeg(`/tmp/${id}/input.mp4`)
  
    .renice(5)
  
    .outputOptions([
  
      '-ss 0',
  
      '-to 15',
  
      '-c copy'
  
    ])
  
    .on('end', () => {})
  
    .on('error', (e, stdout, stderr) => {})
  
    .save(`/tmp/${id}/clip-01.mp4`);

  No need for re-encoding, no need for precise timestamps (1 second out of sync is OK)
  Any thoughts or ideas would be greatly appreciated !