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• ffmpeg - HLS stream audio error between segmets

  2 février 2019, par Carl

  I have a huge amount of mp4 files to create HLS segments from, more than 200 hours worth of files. I don’t see the point of re-encoding these videos because they are already in mp4 format. I’m using the following command which copies the video into segments instead of encoding it again.

  ffmpeg -i filename.mp4 -codec: copy -start_number 0 -hls_time 4 -hls_list_size 0 -f hls filename.m3u8

  The problem is when it comes to stitching these segments, I’m getting micro audio errors between segments. It’s hard to explain but imagine somebody turning audio off for 0.1 seconds. I doesn’t happen in all of the segments but in 20%-30% of them. Is there anything I can do stop these errors from popping up apart from reencoding all the videos. There are no problems with video btw.

  Here’s media info from one of the files :

  General
  Complete name : C :\video_test\video_file.mp4
  Format : MPEG-4
  Format profile : Base Media / Version 2
  Codec ID : mp42 (isom/iso2/avc1/mp41/mp42)
  File size : 45.7 MiB
  Duration : 7 min 34 s
  Overall bit rate mode : Variable
  Overall bit rate : 844 kb/s
  Writing application : Lavf53.32.100
  

  Video
  ID : 1
  Format : AVC
  Format/Info : Advanced Video Codec
  Format profile : High@L4
  Format settings, CABAC : Yes
  Format settings, RefFrames : 8 frames
  Codec ID : avc1
  Codec ID/Info : Advanced Video Coding
  Duration : 7 min 34 s
  Bit rate : 767 kb/s
  Width : 1 280 pixels
  Height : 720 pixels
  Display aspect ratio : 16:9
  Frame rate mode : Constant
  Frame rate : 30.000 FPS
  Color space : YUV
  Chroma subsampling : 4:2:0
  Bit depth : 8 bits
  Scan type : Progressive
  Bits/(Pixel*Frame) : 0.028
  Stream size : 41.5 MiB (91%)
  Writing library : x264 core 136
  Encoding settings : cabac=1 / ref=8 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=6 / psy=0 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=48 / lookahead_threads=5 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=0 / keyint=60 / keyint_min=30 / scenecut=0 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

  Audio
  ID : 2
  Format : AAC
  Format/Info : Advanced Audio Codec
  Format profile : LC
  Codec ID : 40
  Duration : 7 min 34 s
  Bit rate mode : Variable
  Bit rate : 72.0 kb/s
  Maximum bit rate : 96.0 kb/s
  Channel(s) : 2 channels
  Channel positions : Front : L R
  Sampling rate : 44.1 kHz
  Frame rate : 43.066 FPS (1024 SPF)
  Compression mode : Lossy
  Stream size : 3.92 MiB (9%)
  Language : English
  Default : Yes
  Alternate group : 1
  

  Edit : I just tried copying video and reencoding the audio with the following command but problem still persists.

  ffmpeg -i filename.mp4 -vcodec copy -c:a aac -ar 48000 -b:a 128k -start_number 0 -hls_time 4 -hls_list_size 0  -f hls filename.m3u8

• ffmpeg HLS Multiple Audio Renditions

  28 mai 2020, par sylvain

  How can I convert an mp4 video file having inside 3 audio tracks (english, german and french) to an HLS playlist having :

  



  

  • one videofile.m3u8 and its corresponding segmentsfile.ts

  


  • one audiofile-english.m3u8 and its corresponding segmentsfile.aac

  


  • one audiofile-german.m3u8 and its corresponding segmentsfile.aac

  


  • one audiofile-french.m3u8 and its corresponding segmentsfile.aac

  


  • one masterfile.m3u8 like that :

  


  



  #EXTM3U

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="medium",NAME="#1 Fre",DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="fre",URI="medium/planete_interdite_500_h264_240p_audio1_fre.m3u8"

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="medium",NAME="#2 Eng",DEFAULT=NO,AUTOSELECT=YES,LANGUAGE="eng",URI="medium/planete_interdite_500_h264_240p_audio2_eng.m3u8"

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="medium",NAME="#3 Fre",DEFAULT=NO,AUTOSELECT=YES,LANGUAGE="de",URI="medium/planete_interdite_500_h264_240p_audio1_de.m3u8"

#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=3274000, CODECS="avc1.66.30,mp4a.40.2",RESOLUTION=854x480,AUDIO="medium"
medium/planete_interdite_2080_q264_480p.m3u8


  


• using ffmpeg to resize video with black bars

  23 juillet 2018, par Jens S

  i have a video with resolution 720:576 and i want it to have the ratio 16:9, e.g. 1024:576 with black bars on the sides. don’t know if it matters, but i am working with ffmpeg for windows. After research i tried the solution i found on 2 related questions :

  -i .\video.mp4 -vf scale=1024:576:force_original_aspect_ratio=decrease,pad=1024:576:(ow-iw)/2:(oh-ih)/2,setsar=1 out.mp4

  but i get an output that "ow-iw" was not recognized. Here is the complete output. unfortunatly it is in german(as am i) if u tell me how to change the output language i will provide it in english :

  ow-iw : Die Benennung "ow-iw" wurde nicht als Name eines Cmdlet, einer Funktion, einer Skriptdatei oder eines ausführbaren Programms erkannt. Überprüfen Sie die Schreibweise des
  
  Namens, oder ob der Pfad korrekt ist (sofern enthalten), und wiederholen Sie den Vorgang.
  
  In Zeile:1 Zeichen:119
  
  + ... :576:force_original_aspect_ratio=decrease,pad=1024:576:(ow-iw)/2:(oh- ...
  
  +                                                             ~~~~~
  
      + CategoryInfo          : ObjectNotFound: (ow-iw:String) [], CommandNotFoundException
  
      + FullyQualifiedErrorId : CommandNotFoundException