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• FFMPEG M3U8 Download Is Shortened When Processed

  19 décembre 2022, par Devin Dixon

  I am downloading an m3u8 stream with FFMPEG as such :

  


  timeout 60m ffmpeg -i [feed_url] -movflags isml+frag_keyframe+faststart -bsf:a aac_adtstoasc -vcodec copy -c copy [save_file].mp4


  


  

  • The timeout will automatically end the stream after 60. minutes

  


  • The -movflags isml+frag_keyframe+faststart makes sure the moov atom is present for partial downloads and if the stream is cut off.

  


  


  This works fine when I play it in Quicktime or Safari.The stream is then uploaded to another server and it gets processed with this ffmpeg command :

  


  ffmpeg  -i [input_file] -y  -f mp4 -pix_fmt yuv420p -c:v libx264 -c:a aac -filter_complex "scale='if(gt(iw,1920),1920,-1)':'if(gt(ih,1080),1080,-1)':force_original_aspect_ratio=decrease" -crf 20 -movflags faststart -max_muxing_queue_size 9999 -attempt_recovery 1 -max_recovery_attempts 3 -f mp4 [output_file]


  


  When the above command is run, sometimes this error occurs :

  


  [mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] Packet corrupt (stream = 0, dts = 53801910).=  64x     
[NULL @ 0xaaaafcd649b0] Invalid NAL unit size (1186 > 532).
[NULL @ 0xaaaafcd649b0] missing picture in access unit with size 542
/code/partners/tmp/video_634d29a2e1f6e.mp4: corrupt input packet in stream 0
[h264 @ 0xaaaafd1211f0] Invalid NAL unit size (1186 > 532).
[h264 @ 0xaaaafd1211f0] Error splitting the input into NAL units.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] stream 0, offset 0x3802b2: partial file
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] stream 0, offset 0x380791: partial file
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] stream 0, offset 0x380c38: partial file
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] stream 0, offset 0x380f8d: partial file
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] stream 0, offset 0x38137a: partial file
Error while decoding stream #0:0: Invalid data found when processing input
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xaaaafcd63b70] stream 0, offset 0x381750: partial file
[mp4 @ 0xaaaafcd743d0] Starting second pass: moving the moov atom to the beginning of the file
frame= 8967 fps=923 q=-1.0 Lsize=    5683kB time=00:09:57.60 bitrate=  77.9kbits/s speed=61.5x    
video:5580kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.843884%


  


  When this error occurs, the video is cut short. If the full video is 60 minutes that error occurs at the 10 minute mark, the converted video will only be 10 minutes. What is that error and how can I get ffmpeg to stop cutting the output video short ?

  


• aacdec_usac : fix typo in fac_length

  2 juin 2024, par Lynne

  aacdec_usac : fix typo in fac_length
  The spec says :
  
  fac_length = (window_sequence==EIGHT_SHORT_SEQUENCE) ? ccfl/16 : ccfl/8 ;
  The length used was flipped for short vs long.
  

  • [DH] libavcodec/aac/aacdec_usac.c

• Audio drifts when concatenating clips

  18 septembre 2015, par user230013

  I am trying to concatenate a bunch of short, 1-second video clips in ts format using the following command :

  var convertCommand = "cd clips; ffmpeg -y -i concat:\"" + convertedFilenames.join("|") + "\" -c:a aac -strict experimental -bsf:a aac_adtstoasc \"" + user._id + ".mp4\"; mv \"" + user._id + ".mp4\" \"full/" + user._id + ".mp4\"";

  This works great, however, the audio "drifts" very slowly, and after about 15 seconds, the audio has been delayed by about 1 second.

  Is there a way I can encode audio differently to avoid this ? Does this have to do with these commands ?

  -c:a aac -strict experimental -bsf:a aac_adtstoasc 

  For completion, this is the script used to trim the clips first into 1 second clips :

  cd clips; ffmpeg -y -i ./converted/${1}.ts -ss 00:00:00 -t 00:00:01 -vcodec libx264 -acodec libvo_aacenc -y  ./converted/${1}_trimmed.ts;       

  Thanks a lot in advance.