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• Révision 22712 : Cette branche devient la version 3.2.0-dev

  7 janvier 2016, par cedric@yterium.com

  La constante _DEV_PLUGINS qui ne marchait pas très bien est remplacée par la constante _DEV_VERSION_SPIP_COMPAT qui indique que la branche est compatible avec une autre version de SPIP et que tous les plugins qui marchent avec cette autre version sont présumés marcher avec la version courante.

  Pendant la phase de dev on definit cette constante par defaut à la dernière version stable, pour faciliter l’utilisation avec le parc de plugin qui fonctionne dans cette version stable. Quand on passera en beta/rc/release, la definition de la constante sera supprimée

• MPEG-DASH - Multiplexed Representations Issue

  26 avril 2017, par Mike

  I’m trying to learn ffmpeg, MP4Box, and MPEG-DASH, but I’m running into an issue with the .mp4 I’m using. I’m using ffmpeg to demux the mp4 with this command :

  ffmpeg -i test.mp4 -c:v copy -g 72 -an video.mp4 -c:a copy audio.mp4

  Once the two files are created, I use MP4Box to segment the files for the dash player using this command :

  MP4Box -dash 4000 -frag 1000 -rap -segment-name segment_ output.mp4

  Which does create all the files I think I need. Then I point the player to the output_dash.mpd and nothing happens except a ton of messages in the console :

  [8] EME detected on this user agent! (ProtectionModel_21Jan2015) 
  
  [11] Playback Initialized 
  
  [21] [dash.js 2.3.0] MediaPlayer has been initialized 
  
  [64] Parsing complete: ( xml2json: 3.42ms, objectiron: 2.61ms, total: 0.00603s) 
  
  [65] Manifest has been refreshed at Wed Apr 12 2017 12:16:52 GMT-0600 (MDT)[1492021012.196]  
  
  [72] MediaSource attached to element.  Waiting on open... 
  
  [77] MediaSource is open! 
  
  [77] Duration successfully set to: 148.34 
  
  [78] Added 0 inline events 
  
  [78] No video data. 
  
  [79] No audio data. 
  
  [79] No text data. 
  
  [79] No fragmentedText data. 
  
  [79] No embeddedText data. 
  
  [80] Multiplexed representations are intentionally not supported, as they are not compliant with the DASH-AVC/264 guidelines 
  
  [81] No streams to play.

  Here is the MP4Box -info on the video I’m using :

  * Movie Info *
  
      Timescale 1000 - Duration 00:02:28.336
  
      Fragmented File no - 2 track(s)
  
      File suitable for progressive download (moov before mdat)
  
      File Brand mp42 - version 512
  
      Created: GMT Wed Feb  6 06:28:16 2036
  
  
  
  File has root IOD (9 bytes)
  
  Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
  
  Visual PL: Not part of MPEG-4 Visual profiles (0xfe)
  
  Audio PL: Not part of MPEG-4 audio profiles (0xfe)
  
  No streams included in root OD
  
  
  
  iTunes Info:
  
      Name: Rogue One - A Star Wars Story
  
      Artist: Lucasfilm
  
      Genre: Trailer
  
      Created: 2016
  
      Encoder Software: HandBrake 0.10.2 2015060900
  
      Cover Art: JPEG File
  
  
  
  Track # 1 Info - TrackID 1 - TimeScale 90000 - Duration 00:02:28.335
  
  Media Info: Language "Undetermined" - Type "vide:avc1" - 3552 samples
  
  Visual Track layout: x=0 y=0 width=1920 height=816
  
  MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
  
  AVC/H264 Video - Visual Size 1920 x 816
  
      AVC Info: 1 SPS - 1 PPS - Profile High @ Level 4.1
  
      NAL Unit length bits: 32
  
      Pixel Aspect Ratio 1:1 - Indicated track size 1920 x 816
  
  Self-synchronized
  
  
  
  Track # 2 Info - TrackID 2 - TimeScale 44100 - Duration 00:02:28.305
  
  Media Info: Language "English" - Type "soun:mp4a" - 6387 samples
  
  MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
  
  MPEG-4 Audio MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 44100
  
  Synchronized on stream 1
  
  Alternate Group ID 1

  I know I need to separate the video and audio and I think that’s where my issue is. The command I’m using probably isn’t doing the right thing.

  Is there a better command to demux my mp4 ?
  Is the MP4Box command I’m using best for segmenting the files ?
  If I use different files, will they always need to be demuxed ?

  One thing to mention, if I use the following commands everything works fine, but there is no audio because of the -an which means it’s only video :

  ffmpeg -i test.mp4 -c:v copy -g 72 -an output.mp4
  
  
  
  MP4Box -dash 4000 -frag 1000 -rap -segment-name segment_ output.mp4

  UPDATE

  I noticed that the video had no audio stream, but the audio had the video stream which is why I got the mux error. I thought that might be an issue so I ran this command to keep the unwanted streams out of the outputs :

  ffmpeg -i test.mp4 -c:v copy -g 72 -an video.mp4 -c:a copy -vn audio.mp4

  then I run :

  MP4Box -dash 4000 -frag 1000 -rap -segment-name segment_ video.mp4 audio.mp4

  now I no longer get the Multiplexed representations are intentionally not supported... message, but now I get :

  [122] Video Element Error: MEDIA_ERR_SRC_NOT_SUPPORTED 
  
  [123] [object MediaError] 
  
  [125] Schedule controller stopping for audio 
  
  [126] Caught pending play exception - continuing (NotSupportedError: Failed to load because no supported source was found.)

  I tried playing the video and audio independently through Chrome and they both work, just not through the dash player. Ugh, this is painful to learn, but I feel like I’m making progress.

• Serving static video content directly vs. via adaptive streaming protocols (HLS, DASH)

  7 mai 2020, par astralmaster

  Is there an advantage of serving static video content (not a live stream) via adaptive streaming protocols such as HLS or DASH over serving them directly as files using HTTP server in terms of speed ?

  



  Example case is when you have a 500MB mp4 h264+AAC video that you have to serve on a website via HTML5 video element. Would you rather serve it directly, since most popular browsers implement functions such as seek without downloading the whole file first ; or would you rather use ffmpeg or similar solution to create HLS chunks from the mp4 file and instead provide .m3u8 playlist source to the HTML5 video element. Is there a real advantage in terms of speed of doing this ?

  



  Which one would you implement if you had hundreds of video files all served as static content ?