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• ffmpeg decode multiple streams at same time

  29 février 2012, par broschb

  I am using ffmpeg to decode a file and play it back on an android device. I have this working and would now like to decode two streams at the same time. I have read some comments regarding needing to use av_lockmgr_register() call with ffmpeg, unfortunately I am not sure how to use these and how the flow would work when using these locks.

  Currently I have seperate threads on the java side making requests through JNI to native code that is communicating with ffmpeg.

  Do the threads need to be on the native(NDK) side, or can I manage them on the java side ? And do I need to do any locking, and if so how does that work with ffmpeg ?

  ***UPDATE
  I have this working now, it appears that setting up the threads at the java sdk level transfers into separate threads at the native level. With that I was able to create a struct with my variables, and then pass a variable to the native layer to specify what struct to use for each video. So for I have needed to use any mutexs or locks at the native level, and haven't had any issues.

  Does anyone know of potential gotchas I may encounter by not doing so with ffmpeg ?

• 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.

• MP4 to DASH (bash script)

  13 mars 2017, par francesco.galgani

  I have a web site in which users can upload video files. I want to stream all of them using DASH to obtain an adaptive bitrate streaming. So I wrote a bash script (to run by cron) that converts all mp4 files to DASH, but it doesn’t work properly : what is wrong ?

  For example, using the following script, I obtained :
  https://www.informatica-libera.net/dash_faq/stream.mpd

  It validates, but it doesn’t play. I tested it on :
  http://dash-mse-test.appspot.com/dash-player.html?url=https%3A%2F%2Fwww.informatica-libera.net%2Fdash_faq%2Fstream.mpd&autoplay=on&adapt=auto&flavor=

  Thank you for any help.
  The code :

  #!/bin/bash
  
  
  
  # THIS SCRIPT CONVERTS EVERY MP4 (IN THE CURRENT FOLDER AND SUBFOLDER)
  
  # TO A MULTI-BITRATE VIDEO IN MP4-DASH
  
  # For each file "videoname.mp4" it creates a folder "dash_videoname" 
  
  # containing a dash manifest file "stream.mpd" and subfolders containing 
  
  # video segments.
  
  
  
  # mp4dash documentation and download: https://www.bento4.com/developers/dash/
  
  
  
  MYDIR=$(dirname $(readlink -f ${BASH_SOURCE[0]}))
  
  SAVEDIR=$(pwd)
  
  
  
  # Check programs
  
  if [ -z "$(which ffmpeg)" ]; then
  
      echo "Error: ffmpeg is not installed"
  
      exit 1
  
  fi
  
  
  
  if [ -z "$(which mp4dash)" ]; then
  
      echo "Error: mp4dash is not installed"
  
      exit 1
  
  fi
  
  
  
  cd "$MYDIR"
  
  
  
  TARGET_FILES=$(find ./ -type f -name "*.mp4")
  
  for f in $TARGET_FILES
  
  do
  
    f=$(basename "$f") # fullname of the file
  
    f="${f%.*}" # name without extension
  
  
  
    if [ ! -d "dash_${f}" ]; then
  
      echo "Converting \"$f\" to multi-bitrate video in MPEG-DASH"
  
  
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 1500k -vf "scale=-2:720" -f mp4 -pass 1 -y /dev/null
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 1500k -vf "scale=-2:720" -f mp4 -pass 2 "${f}_1500.mp4"
  
  
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 800k -vf "scale=-2:540" -f mp4 -pass 1 -y /dev/null
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 800k -vf "scale=-2:540" -f mp4 -pass 2 "${f}_800.mp4"
  
  
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 400k -vf "scale=-2:360" -f mp4 -pass 1 -y /dev/null
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 400k -vf "scale=-2:360" -f mp4 -pass 2 "${f}_400.mp4"
  
  
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 200k -vf "scale=-2:180" -f mp4 -pass 1 -y /dev/null
  
      ffmpeg -y -i "${f}.mp4" -c:a libfdk_aac -ac 2 -ab 128k -c:v libx264 -x264opts 'keyint=24:min-keyint=24:no-scenecut' -b:v 200k -vf "scale=-2:180" -f mp4 -pass 2 "${f}_200.mp4"
  
  
  
      rm -f ffmpeg*log*
  
  
  
      mp4fragment "${f}_1500.mp4" "${f}_1500_fragmented.mp4"
  
      mp4fragment "${f}_800.mp4" "${f}_800_fragmented.mp4"
  
      mp4fragment "${f}_400.mp4" "${f}_400_fragmented.mp4"
  
      mp4fragment "${f}_200.mp4" "${f}_200_fragmented.mp4"
  
  
  
      rm -f "${f}_1500.mp4" "${f}_800.mp4" "${f}_400.mp4" "${f}_200.mp4"
  
  
  
      mp4dash -v -o "dash_${f}" "${f}_1500_fragmented.mp4" "${f}_800_fragmented.mp4" "${f}_400_fragmented.mp4" "${f}_200_fragmented.mp4"
  
  
  
      rm -f "${f}_1500_fragmented.mp4" "${f}_800_fragmented.mp4" "${f}_400_fragmented.mp4" "${f}_200_fragmented.mp4"
  
  
  
      fi
  
  
  
  done
  
  
  
  cd "$SAVEDIR"