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• ffmpeg can't transcode DVD ac3 audio stream, but VLC can play it

  21 février 2020, par RalphORama

  I’m attempting to transcode a DVD to a single MKV file. I’ve had success in the past with other DVDs, but I’m running into an error I haven’t seen before.

  First I concatenate the VOB files I want to transcode :

  cat VTS_02_1.VOB VTS_02_2.VOB VTS_02_3.VOB > WMAV.VOB

  ffprobe output :

  $ ffprobe -analyzeduration 100M -probesize 100M WMAV.VOB                                                                         Input #0, mpeg, from 'WMAV.VOB':
  
    Duration: 01:05:19.42, start: 0.300300, bitrate: 5686 kb/s
  
      Stream #0:0[0x1bf]: Data: dvd_nav_packet
  
      Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, smpte170m, top first), 720x480 [SAR 32:27 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
  
      Stream #0:2[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
  
  Unsupported codec with id 100357 for input stream 0

  Then I run this command to transcode the file :

  ffmpeg -analyzeduration 100M -probesize 100M \
  
    -i WMAV.VOB \
  
    -map 0:1 -map 0:2 \
  
    -c:v libx264 -preset slow -tune film -crf 21 \
  
    -c:a aac -b:a 192k \
  
    wmav.mkv

  However, when I include -c:a aac, I get thousands of errors like this :

  Error while decoding stream #0:2: Error number -16976906 occurred
  
  [ac3 @ 000002bd24d8eec0] expacc 127 is out-of-range
  
  [ac3 @ 000002bd24d8eec0] error decoding the audio block

  There doesn’t seem to be any issue with the audio stream since it plays back fine in VLC. The transcode succeeds if I use -c:a copy.

  What is causing this error and how could I fix the problem ?

• FFMPEG use -strict -2

  21 août 2020, par GILO

  Hi I've been recently using the command below

  


  Ffmpeg -i song.mp3 -loop 1 -i image.jpg -filter_complex \
"[0:a]showfreqs=mode=line:ascale=log:fscale=log:s=1280x518[sf]; \
 [0:a]showwaves=s=1280x202:mode=p2p[sw]; \
 [sf][sw]vstack[fg]; \
 [1:v]scale=1280:-1,crop=iw:720[bg]; \
 [bg][fg]overlay=shortest=1:format=auto,format=yuv420p,drawtext=fontfile=/usr/share/fonts/TTF/Vera.ttf:fontcolor=white:x=10:y=10:text='\"Rated80s Prophets Prey\" by Comics On Film'[out]" \
-map "[out]" -map 0:a -c:v libx264 -preset fast -crf 18 -c:a libopus output.mp4 


  


  from this post Showfreqs and showwaves over background image ?.

  


  


  However I changed the output file to from output.mkv to output.mp4 as I would prefer to use mp4

  


  


  I get the below error

  


  [mp4 @ 0x7f962b816800] opus in MP4 support is experimental, add '-strict -2' if you want to use it.
Could not write header for output file #0 (incorrect codec parameters ?) : Experimental feature
Error initializing output stream 0:0 —
[libopus @ 0x7f962b819800] 1 frames left in the queue on closing

  


  The main information from that error is

  


  


  opus in MP4 support is experimental, add '-strict -2' if you want to use it.

  


  


  but where do I use -strict -2 within the command to make the command possible

  


• How to fix corrupt video caused by amix filter - FFMPEG

  22 octobre 2019, par EJL

  I am trying to put text and audio in a video using FFMPEG. It is weird because the output is corrupted and the video timeline stop counting the video time currently playing. And also, some portions of the video are missing and even freezing/hanging.

  I already tried to search for this including updating my computers OS (Centos 7). Also, updating, upgrading ffmpeg build in my unit but still no luck.

  I am generating the video using this command :

  ffmpeg -i input.mp4 \
  
  -i mouse_click.mp3 \
  
  -i typing.mp3 \
  
  -filter_complex "[0:v]drawbox=enable='between(t,84,87)':y=ih-ih/5:color=black@1.0:width=iw:height=72:t=max,drawbox=enable='between(t,97,102)':y=ih-ih/5:color=black@1.0:width=iw:height=72:t=max,drawbox=enable='between(t,100,101)':x=622:y=682:w=93:h=31:color=red,drawtext=enable='between(t,84,86)':fontfile=fonts/RobotoBoldCondensed.ttf:text='Enter "admin-pc"...':fontcolor=white:fontsize=24:x=50:y=h-h/5+20,drawtext=enable='between(t,98,99)':fontfile=fonts/RobotoBoldCondensed.ttf:text='Finding "Use express settings"...':fontcolor=white:fontsize=24:x=50:y=h-h/5+20,drawtext=enable='between(t,100,101)':fontfile=fonts/RobotoBoldCondensed.ttf:text='Text Found':fontcolor=white:fontsize=24:x=50:y=h-h/5+20[video];[1]adelay=102000|102000,volume=15dB[s1];[2]adelay=84000|84000,volume=15dB[s0];[s0][s1] amix=inputs=2:duration=first:dropout_transition=0,dynaudnorm [click_sound]" \
  
  -map "[video]" \
  
  -map "[click_sound]" \
  
  -pix_fmt yuv420p \
  
  -c:a mp3 output.mp4

  I tried to remove the audio script by removing these lines :

  [1]adelay=102000|102000,volume=15dB[s1] ;
  [2]adelay=84000|84000,volume=15dB[s0] ;
  [s0][s1] amix=inputs=2:duration=first:dropout_transition=0,dynaudnorm [click_sound]

  and removing the

  -map "[click_sound]"

  , the video is working fine and is not corrupted. I believe it is becuase of the amix filter or something else but I cannot figure it out.

  The output should be a working video.

  Any response will be appreciated. Thank you.