Sur d’autres sites (10664)

• HLS Streaming on IPad with IOS 7 / 8 causes 10 seconds freezed frame - no clue why

  25 juin 2014, par user3747636

  We have a problem with HLS h.264 mp4 on IPad devices using HLS streaming on IOS 7 and 8 :

  The first 9-15 seconds (the length of the first TS segment) only shows the first key frame (IDR) of the second TS segment, while the sound plays normally. When the second segment begins to play, the video continues as it should.

  HLS segmenter is a wowza with 10 seconds segment length. The encoding software we use is TMPG, latest version (uses x264). The funny thing is, that handbrake, xmedia recode, adobe me deliver videos which work. I am aware of the fact, that this hints to a bug within our encoding software, but if someone already had that problem with another software / segmenter combination and fixed it, I would like to know what the source of the problem was.

  What we already tried :

  • changing almost every setting so that it sticks as close as possible to apple’s recommendations
  • changing GOP structure, GOP length, encoding parameters which influence efficiency of encoding
  • analysis of the TS segments created by wowza, they are fine and begin all with keyframes
  • contact TMPG/Apple/Wowza support

  So, did anyone stumble upon this problem before ? Has anyone solved it ?

  EDIT :

  It seems that TMPGEnc uses a defective x264 implementation. The mediastreamvalidator tool from Apple returned an error stating that our TS segment "does not contain any IDR access unit with a SPS and a PPS" - which it does actually, but obviously in the wrong places if that somehow matters.

• Creating marketing videos

  7 juin 2020, par Cengiz

  I am trying to create a marketing video with multiple images (png/jpg) after adding texts on every single image and of course with their duration. Therefor, I use several ffmpeg commands, because I am not able to do it with just one command.

  



  How can I define a text and a duration for every image before adding it to the video ?

  



  My example batch file :

  



   !/bin/bash

  



  echo "[Start]"
ffmpeg \
 -i '01.jpg' \
 -vf drawtext="\text='Stack Overflow' : fontcolor=white : fontsize=24 : box=1 : boxcolor=black@0.9 : boxborderw=5 : x=(w-text_w)/2 : y=(h-text_h)/2" \
 -codec:a copy \
 -y 'out-a.mp4'
ffmpeg \
 -i '02.jpg' \
 -vf drawtext="\text='Another Text' : fontcolor=white : fontsize=24 : box=1 : boxcolor=black@0.9 : boxborderw=5 : x=(w-text_w)/2 : y=(h-text_h)/2" \
 -codec:a copy \
 -y 'out-b.mp4'
ffmpeg \
 -i '03.jpg' \
 -vf drawtext="\text='Hello World' : fontcolor=white : fontsize=24 : box=1 : boxcolor=black@0.9 : boxborderw=5 : x=(w-text_w)/2 : y=(h-text_h)/2" \
 -codec:a copy \
 -y 'out-c.mp4'
ffmpeg \
 -i out-*.mp4 \
 -vf scale=768x420 \
 -c:v libx264 \
 -r 30 \
 -pix_fmt yuv420p \
 -y 'output.mp4'
echo "[End]"

  



  Thanks to all
Cengiz

  


• Révision 112346 : Nettoyer les referers en enlevant les variables de personnalisation marketing, o...

  6 novembre 2018, par booz@rezo.net