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• Convert PNGs to webm video with transparency

  20 septembre 2016, par sebastian

  I would like to use avconv to convert a series of PNG images to a WebM video, preserving transparency.

  I understand that the pixel format used in the output video must support transparency. So I tried :

  $ avconv -framerate 25 -f image2 -i frames/%03d.png -pix_fmt yuva420p output.webm

  Unfortunately, avconv complains :

  Incompatible pixel format 'yuva420p' for codec 'libvpx-vp9', auto-selecting format 'yuv420p'

  I am using ffmpeg version 2.8.4-1+b1 Copyright (c) 2000-2015 the FFmpeg developers.

• Unable to execute CLI commands through PHP

  13 janvier 2012, par user940154

  OS : ubuntu 11.10
  Webserver : Apache
  Code : PHP
  I am trying to display the output of command "ffmpeg -i " on the webpage using php.
  Required : The webpage should show the information about video (text).
  Whats happening : The webpage shows no text output on running the php code.
  If I was however doing system("ls") the code runs fine and outputs the list of files.
  Here's my code

  <?php
  
   echo "Details of video file:";
  
   system('ffmpeg -i /home/atish/Videos/T2V0040006_Angled_ride_720x576i_FLDCMB.avi');
  
  ?>

  The same command works fine on my shell, and my system has ffmpeg installed. Here's a snapshot of executing this command directly on shell :

  ThinkPad-T420:~/Videos$ ffmpeg -i /home/xx/Videos/T2V0040006_Angled_ride_720x576i_FLDCMB.avi
  
  ffmpeg version git-2012-01-10-7e2ba2d Copyright (c) 2000-2012 the FFmpeg developers
  
  built on Jan 10 2012 12:01:19 with gcc 4.6.1
  
  configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-    amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab
  
    libavutil      51. 34.100 / 51. 34.100
  
    libavcodec     53. 54.100 / 53. 54.100
  
    libavformat    53. 29.100 / 53. 29.100
  
    libavdevice    53.  4.100 / 53.  4.100
  
    libavfilter     2. 58.100 /  2. 58.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0.  6.100 /  0.  6.100
  
    libpostproc    51.  2.100 / 51.  2.100
  
    Input #0, avi, from '/home/atish/Videos/T2V0040006_Angled_ride_720x576i_FLDCMB.avi':
  
    Metadata:
  
    encoder         : Lavf52.23.1
  
    Duration: 00:00:29.00, start: 0.000000, bitrate: 124422 kb/s
  
    Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 720x576, 25 tbr, 25 tbn, 25 tbc
  
    At least one output file must be specified

  I have tried appending "DISPLAY=:0" to my command and also done "xhost +" before running php code, but nothing is helping me out.

  Thanks.

• ffmpeg usage to encode a video to H264 codec format

  20 août 2015, par goldenmean

  I have a *.mp4 video file(MPEG4 video codec) and I am trying to convert this to a H264 video codec format(raw h.264 format) using ffmpeg on Linux(Version - FFmpeg version SVN-r0.5.1-4:0.5.1-1ubuntu1, Copyright (c) 2000-2009 Fabrice Bellard,) using command line as shown below,

  ffmpeg -i input .mp4 output.h264 

  but I get an error saying -

  Unsupported codec for output stream #0.0

  Then when i try this option :

  ffmpeg -i input .mp4 -formats h264 output.h264 

  it still does not work, and gives -

  Seems stream 0 codec frame rate differs from container frame rate: 59.94 (5994/100) -> 29.97 (30000/1001)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Rapture.mp4':
  
    Duration: 00:02:06.44, start: 0.000000, bitrate: 26574 kb/s
  
      Stream #0.0(eng): Video: h264, yuv420p, 1920x1080, 29.97 tbr, 29.97 tbn, 59.94 tbc
  
      Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16

  And then it prints out help on the formats which we get when we do ffmpeg -formats

  When I checked the help, ffmpeg -formats, I see below information related to H264 file format and codec :

  File format : 
  
  
  
  DE h264            raw H.264 video format
  
  
  
  Codecs:
  
  
  
  D V D  h264         H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10

  My questions :

  1. How can I convert the video to a H264 encoded video (raw H264 video format)

  2. When I do ffmpeg -formats, I see many acronyms for the codecs supported, I see many acronyms before the codec name/type such as - D V D S E A, what do they stand for ?

  3. How to use the ffmpeg options -vcodec and -formats ?