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• FFMPEG H.264 encoding for HTML5 (and ultimately MPEG-DASH)

  18 juin 2015, par Thane Thomson

  I want to convert an MP4 file to an MPEG-DASH video capable of being played through the DASH-IF HTML5 player on Chrome. I use FFMPEG and MP4Box (from GPAC) to transcode the video and then split it, and keep getting a MEDIA_ERR_SRC_NOT_SUPPORTED error on the JavaScript console.

  From the (very sparse) information available online (see this Chromium thread), it would appear as though Chrome natively only supports MP4 files with the Constrained Baseline encoding profile, and is very strict on only supporting the "avc1.42E01E,mp4a.40.2" codecs.

  I have tried pretty much everything I can to encode the video from the command line, prior to splitting with MP4Box, with FFMPEG to get an H.264 video encoding with codec profile "avc1.42E01E", but it just keeps giving me "avc1.42C01E". Here’s one of the (many) FFMPEG commands I’ve tried :

  ffmpeg -y -i Sintel_-_Third_Open_Movie_by_Blender_Foundation.mp4 -profile:v baseline -level:v 30 -acodec libvo_aacenc -vcodec libx264 sintel-recoded.mp4

  According to the ITU-T standard, sections 7.4.2.1.1 and A2.1-A2.3, a video encoding of "avc1.42E01E" implies constraint flags of 0xE0 (constraint_set flags 0, 1 and 2 are set), whereas "avc1.42C01E" implies constraint flags of 0xC0 (constraint_set flags 0 and 1 are set). The former (0xE0) implies conformance to the Baseline, Main and Extended profiles, whereas the latter (0xC0) implies conformance to only the Baseline and Main profiles.

  Apparently, FFMPEG doesn’t support the Extended profile for H.264.

  Does anyone perhaps have any advice as to how to encode an MP4 file as "avc1.42E01E" ? Ideally with FFMPEG, but I am open to using other encoders ?

• Framerate live streaming webm with dash and ffmpeg

  14 mai 2016, par Jones

  I am streaming a live video with ffmpeg and dash.js using
  these instructions. It works well except that the video is playing at a too high framerate. No framerate is specified in the manifest.
  Creating the Chunks :

  SET VP9_LIVE_PARAMS=-speed 6 -threads 8 -static-thresh 0 -max-intra-rate 300 -deadline realtime -lag-in-frames 0 -error-resilient 1
  
  ffmpeg -re -r 25 -i tcp://localhost:8891 ^
  
  -map 0:0 ^
  
    -pix_fmt yuv420p ^
  
    -c:v libvpx-vp9 ^
  
      -s 800x600 -keyint_min 25 -g 25 %VP9_LIVE_PARAMS% ^
  
      -f webm_chunk ^
  
      -header "webm_live/glass_360.hdr" ^
  
      -chunk_start_index 1 ^
  
    webm_live\glass_360_%%d.chk ^

  Creating the Manifest :

  ffmpeg ^
  
    -f webm_dash_manifest -live 1 ^
  
     -r 25 ^
  
    -i webm_live/glass_360.hdr ^
  
    -c copy ^
  
    -map 0 ^
  
    -r 25 ^
  
    -framerate 25 ^
  
    -f webm_dash_manifest -live 1 ^
  
      -adaptation_sets "id=0,streams=0" ^
  
      -chunk_start_index 1 ^
  
      -chunk_duration_ms 1000 ^
  
      -time_shift_buffer_depth 7200 ^
  
      -minimum_update_period 7200 ^
  
    webm_live/glass_live_manifest.mpd

  Manifest :

  <?xml version="1.0" encoding="UTF-8"?>
  
  <mpd xmlns="urn:mpeg:DASH:schema:MPD:2011" type="dynamic" minbuffertime="PT1S" profiles="urn:mpeg:dash:profile:isoff-live:2011" availabilitystarttime="2016-03-30T13:02:53Z" timeshiftbufferdepth="PT7200S" minimumupdateperiod="PT7200S">
  
  <period start="PT0S">
  
  <adaptationset mimetype="video/webm" codecs="vp9" bitstreamswitching="true" subsegmentalignment="true" subsegmentstartswithsap="1">
  
  <contentcomponent type="video"></contentcomponent>
  
  <segmenttemplate timescale="1000" duration="1000" media="glass_$RepresentationID$_$Number$.chk" startnumber="1" initialization="glass_$RepresentationID$.hdr"></segmenttemplate>
  
  <representation bandwidth="1000000" width="800" height="600" codecs="vp9" mimetype="video/webm" startswithsap="1"></representation>
  
  </adaptationset>
  
  </period>
  
  </mpd>

  Any Ideas how to fix this ?

• Is it possible to stream multi framerate videos using MPEG-DASH ?

  7 mars 2016, par Diago mysskin

  I transcoded a mp4 video to several framerates like 5FPS, 10FPS .. 30FPS and used MP4Box to segment them to play in DASH IF player.

  FFMPEG Command to generate multi framerate videos with same resolution :

  ffmpeg -i fball.mp4 -f mp4 -vcodec libx264 -profile:v high -vf scale=1280 :-1 -b:v 2000k -minrate 2000k -maxrate 2000k -bufsize 2000k -nal-hrd cbr -g 120 -keyint_min 120 -r 60.0 -flags +cgop -sc_threshold 0 -pix_fmt yuv420p -threads 0 -x264opts keyint=120:min-keyint=120:sps-id=1 -an -y fball_720p_60fps.mp4

  ffmpeg -i fball.mp4 -f mp4 -vcodec libx264 -profile:v high -vf scale=1280 :-1 -b:v 1000k -minrate 1000k -maxrate 1000k -bufsize 1000k -nal-hrd cbr -g 60 -keyint_min 60 -r 30.0 -flags +cgop -sc_threshold 0 -pix_fmt yuv420p -threads 0 -x264opts keyint=60:min-keyint=60:sps-id=1 -an -y fball_720p_30fps.mp4

  FFMPEG command to extract audio :

  ffmpeg -i fball.mp4 -acodec aac -b:a 128k -vn -strict -2 -y fball_audio.mp4

  MP4Box command for segmentation :

  MP4Box -frag 2000 -dash 2000 -rap -base-url ./segments/ -profile main -segment-name /segments/%s_ -out dash/fball_dash.mpd fball_720p_24fps.mp4 fball_720p_30fps.mp4 fball_720p_60fps.mp4 fball_audio.mp4

  1. Segment Duration : 2 seconds

  2. GOP length : segment duration x FPS of video

  3. Resolution : 720p for all videos

  Result is VIDEO DECODE error or stalls while switching framerate.

  Am I making any mistake while transcoding ?
  Is it possible to stream Multi frame rate videos using MPEG DASH ?