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• Algorithm when recording SegmentTimeline of MPEG-DASH MPD in shaka packager

  25 mars 2021, par jgkim0518

  I packaged a media stream by mpeg-dash transcoded video at twice the speed and audio at normal speed.
Here is the command :

  


  ffmpeg -re -stream_loop -1 -i timing_logic.mp4 -c:v hevc_nvenc -filter:v "setpts=2*PTS" -c:a libfdk_aac -map 0:v -map 0:a -f mpegts udp://xxx.xxx.xxx.xxx:xxxx?pkt_size=1316


  


  The source information used here is as follows :

  


  Input #0, mpegts, from '/home/test/timing_logic/timing_logic.mp4':
Duration: 00:00:30.22, start: 1.400000, bitrate: 16171 kb/s
Program 1
Metadata:
service_name : Service01
service_provider: FFmpeg
Stream #0:0[0x100]: Video: hevc (Main 10) (HEVC / 0x43564548), yuv420p10le(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 50 fps, 50 tbr, 90k tbn, 50 tbc
Stream #0:1[0x101](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, fltp, 128 kb/s Stream mapping:
Stream #0:0 -> #0:0 (hevc (native) -> hevc (hevc_nvenc))
Stream #0:1 -> #0:1 (mp2 (native) -> aac (libfdk_aac))
Press [q] to stop, [?] for help
frame= 0 fps=0.0 q=0.0 size= 0kB time=-577014:32:22.77 bitrate= -0.0kbits/s speed=N/A
frame= 0 fps=0.0 q=0.0 size= 0kB time=-577014:32:22.77 bitrate= -0.0kbits/s speed=N/A
Output #0, mpegts, to 'udp://xxx.xxx.xxx.xxx:xxxx?pkt_size=1316':
Metadata:
encoder : Lavf58.45.100
Stream #0:0: Video: hevc (hevc_nvenc) (Main 10), p010le, 3840x2160 [SAR 1:1 DAR 16:9], q=-1--1, 2000 kb/s, 50 fps, 90k tbn, 50 tbc
Metadata:
encoder : Lavc58.91.100 hevc_nvenc
Side data:
cpb: bitrate max/min/avg: 0/0/2000000 buffer size: 4000000 vbv_delay: N/A
Stream #0:1(eng): Audio: aac (libfdk_aac), 48000 Hz, stereo, s16, 139 kb/s
Metadata:
encoder : Lavc58.91.100 libfdk_aac


  


  My shaka packager command is :

  


  packager \ 'in=udp://xxx.xxx.xxx.xxx:xxxx,stream=video,init_segment=/home/test/timing_logic/package/video/0/video.mp4,segment_template=/home/test/timing_logic/package/video/0/$Time$.m4s' \
'in=udp://xxx.xxx.xxx.xxx:xxxx,stream=audio,init_segment=/home/test/timing_logic/package/audio/0/audio.mp4,segment_template=/home/test/timing_logic/package/audio/0/$Time$.m4a' \
--segment_duration 5 --fragment_duration 5 --minimum_update_period 5 --min_buffer_time 5 \
--preserved_segments_outside_live_window 24 --time_shift_buffer_depth 40 \
--allow_codec_switching --allow_approximate_segment_timeline --log_file_generation_deletion \
--mpd_output $OUTPUT/$output_mpd.mpd &


  


  Looking at the mpd generated as a result of packaging, the duration of the audio is twice that of the video, and the number of segments is half.
The following is the content of mpd :

  


  &lt;?xml version="1.0" encoding="UTF-8"?>&#xA;&#xA;<mpd xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-live:2011" minbuffertime="PT5S" type="dynamic" publishtime="2021-03-23T10:01:57Z" availabilitystarttime="2021-03-23T09:59:55Z" minimumupdateperiod="PT5S" timeshiftbufferdepth="PT40S">&#xA;<period start="PT0S">&#xA;<adaptationset contenttype="audio" segmentalignment="true">&#xA;<representation bandwidth="140020" codecs="mp4a.40.2" mimetype="audio/mp4" audiosamplingrate="48000">&#xA;<audiochannelconfiguration schemeiduri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"></audiochannelconfiguration>&#xA;<segmenttemplate timescale="90000" initialization="/home/test/timing_logic/package/audio/0/audio.mp4" media="/home/test/timing_logic/package/audio/0/$Time$.m4a" startnumber="16">&#xA;<segmenttimeline>&#xA;<s t="6751436" d="449280"></s>&#xA;<s t="7200716" d="451200"></s>&#xA;<s t="7651916" d="449280"></s>&#xA;<s t="8101196" d="374400"></s>&#xA;<s t="8551196" d="449280"></s>&#xA;<s t="9000476" d="451200"></s>&#xA;<s t="9451674" d="449280"></s>&#xA;<s t="9900956" d="449280"></s>&#xA;<s t="10350236" d="451200"></s>&#xA;<s t="10801434" d="374400"></s>&#xA;</segmenttimeline>&#xA;</segmenttemplate>&#xA;</representation>&#xA;</adaptationset>&#xA;<adaptationset contenttype="video" width="3840" height="2160" framerate="90000/3600" segmentalignment="true" par="16:9">&#xA;<representation bandwidth="1520392" codecs="hvc1.2.4.L153" mimetype="video/mp4" sar="1:1">&#xA;<segmenttemplate timescale="90000" initialization="/home/test/timing_logic/package/video/0/video.mp4" media="/home/test/timing_logic/package/video/0/$Time$.m4s" startnumber="19">&#xA;<segmenttimeline>&#xA;<s t="16954440" d="900000" r="4"></s>&#xA;</segmenttimeline>&#xA;</segmenttemplate>&#xA;</representation>&#xA;</adaptationset>&#xA;</period>&#xA;</mpd>&#xA;

  


  When looking at the MPD, it seems that the shaka packager checks the PTS or DTS of the TS when creating a segment and recording the contents of the SegmentTimeline.
But I couldn't understand even by looking at the MPEG standard documentation and the DASH-IF documentation.

  


  My question is whether the packager refers to PTS or DTS when creating a segment.
How are SegmentTimeline's S@t and S@d recorded ?
What algorithm is the SegmentTimeline recorded with ? Please help me. Thank you.

  


• Bash : Create copy of music files in different format and folder

  13 mai 2021, par Brett Sjoholm

  I'm trying to create a bash scipt to simply automate finding my flac files and creating an alac copy of them in a separate folder. Just so I have my little itunes folder. Want to automate because so many.

  


  So I find my flac folders within my Eminem folder....

  


  :~$ find /mnt/music/Eminem -type d -name *FLAC
    /mnt/music/Eminem/2009 Relapse FLAC
    /mnt/music/Eminem/1996 Infinite FLAC
    /mnt/music/Eminem/1999 The Slim Shady LP FLAC
    /mnt/music/Eminem/2000 Marshall Mathers LP FLAC


  


  Now instead of going into each folder and converting manually using something like

  


      ffmpeg -i track.flac -acodec alac track.m4a...


  


  How do I, within a bash script, take these multiple folders. Create an ALAC copy of the contents in /mnt/music/iTunes using FFMpeg ?

  


  New folder will be...

  


  /mnt/music/iTunes/Eminem/2009 Relapse ALAC/track.m4a


  


  All flac folders have FLAC at the end in the same folder structure.

  


  /mnt/music/Artist/Year Album FLAC


  


  I understand most of the locating, copying, converting, manually terminal command stuff but when it comes to putting it into a bash script. I don't understand how I take the output of each command and use it for another. The list of folder for example. Don't know how to automate doing all the steps for each.

  


  Kind of long winded but any help will be much appreciated. Even some videos you recommend for learning.

  


• Anomalie #4830 : extraire_date extravagant

  6 juillet 2021

  Pourquoi pas. Je te propose (ou quelqu’un) de faire une PR pour ça.
  Il faudrait ajouter en même temps des tests unitaires parce que bon.
  Ci dessous un code valide qui fait la demande.

  Ce qui me gène tout de même c’est le [^0-9]* dans la regex (déjà présente dans l’ancienne fonction) qui du coup peut chercher une date coupée dans un grand texte…
  Tel que : "En 2012 à l’orée du bois se trouvait 10 chevaux et 4 biches.", qui sort la date "2012-10-04" (ou 2012-10-01 avant cette proposition).
  Donc l’usage est possiblement assez limité de cette fonction si laissée telle quelle.

  <span class="CodeRay">
  <span class="comment">/**
   * Extrait une date d'un texte et renvoie le résultat au format de date SQL
   *
   * L'année et le mois doivent être numériques.
   * Le séparateur entre l'année et le mois peut être un `-`, un `:` ou un texte
   * quelconque ne contenant pas de chiffres.
   *
   * Si un numéro de jour valide n'est pas indiqué, le résultat est alors le 1er du mois.
   *
   * @link https://www.spip.net/5516
   * @param string $texte
   *    Texte contenant une date tel que `2008-04`
   * @return string
   *    Date au format SQL tel que `2008-04-01`
   **/</span>
  <span class="keyword">function</span> <span class="function">extraire_date</span>(<span class="local-variable">$texte</span>) {
      <span class="comment">// format = 2001-08-12 ou 2001-08</span>
      <span class="local-variable">$has_date</span> = <span class="predefined">preg_match</span>(
          <span class="string"><span class="delimiter">"</span><span class="content">,
          # une annee
          (?P<annee>[1-2][0-9]</annee></span><span class="content">{</span><span class="content">3})
          # des caracteres sans numeros
          [^0-9]*
          # un mois
          (?P<mois>1[0-2]|0?[1-9])
          (?:
              # des caracteres sans numeros
              [^0-9]*
              # un jour
              (?P<jour>3[0-1]|[1-2][0-9]|0?[1-9])
          )?
          ,x</jour></mois></span><span class="delimiter">"</span></span>, 
          <span class="local-variable">$texte</span>, 
          <span class="local-variable">$regs</span>
      );
      <span class="keyword">if</span> (<span class="local-variable">$has_date</span>) {
          <span class="local-variable">$date</span> = [
              <span class="local-variable">$regs</span>[<span class="string"><span class="delimiter">"</span><span class="content">annee</span><span class="delimiter">"</span></span>], 
              <span class="predefined">sprintf</span>(<span class="string"><span class="delimiter">"</span><span class="content">%02d</span><span class="delimiter">"</span></span>, <span class="local-variable">$regs</span>[<span class="string"><span class="delimiter">"</span><span class="content">mois</span><span class="delimiter">"</span></span>]), 
              <span class="predefined">sprintf</span>(<span class="string"><span class="delimiter">"</span><span class="content">%02d</span><span class="delimiter">"</span></span>, <span class="local-variable">$regs</span>[<span class="string"><span class="delimiter">"</span><span class="content">jour</span><span class="delimiter">"</span></span>] ?? <span class="string"><span class="delimiter">"</span><span class="content">01</span><span class="delimiter">"</span></span>) 
          ];
          <span class="keyword">return</span> <span class="predefined">implode</span>(<span class="string"><span class="delimiter">"</span><span class="content">-</span><span class="delimiter">"</span></span>, <span class="local-variable">$date</span>);
      }
  }
  </span>
  Télécharger

  ---

  #SQUELETTE 
  
  
  
  #SET{liste,#LISTE{
  
      "Une date 2020 01",
  
      "Une date 2020 12 autre",
  
      "Une date 2020 autre 12 autre",
  
      "Une date 2021 12 01",
  
      "Une date 2021 12 00",
  
      "Une date 2021 12 31",
  
      "Une date 2021 12 32",
  
      "Une date 2021 autre 12 date 21",
  
      "En 2012 à l’orée du bois se trouvait 10 chevaux et 4 biches." 
  
  }}
  
  
  
  <dl>
  
  
  
  <dt>#VALEUR</dt>
  
  <dd>[(#VALEUR|extraire_date)]</dd>
  
  
  
  </dl>

  ---

  Sortie :

  Une date 2020 01
      2020-01-01
  Une date 2020 12 autre
      2020-12-01
  Une date 2020 autre 12 autre
      2020-12-01
  Une date 2021 12 01
      2021-12-01
  Une date 2021 12 00
      2021-12-01
  Une date 2021 12 31
      2021-12-31
  Une date 2021 12 32
      2021-12-03
  Une date 2021 autre 12 date 21
      2021-12-21
  En 2012 à l’orée du bois se trouvait 10 chevaux et 4 biches.
      2012-10-04 
  Télécharger