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• create an Json file as an output from a ffmpeg command line

  22 juin 2020, par ringola27

  I am trying to put the output I get from a ffmpeg command into a json file.
So I tried :

  


  ffmpeg -i 2.y4m -i netflixboxing.y4m -lavfi "libvmaf=model_path=/usr/local/share/model/vmaf_v0.6.1.pkl" -f null - > out.json 


  


  I get an empty json file. Do i have to specify which information I need in my json file ?

  


  I hope someone can help me.

  


• video playing with paperclip ffmpeg

  30 mars 2014, par Ameya Savale

  I've been having problems playing uploaded videos in my ruby on rails app.

  So I am using the paperclip-ffmpeg gem to process my videos when uploaded, and I am able to create a thumbnail of the video but I am not able to play the video. When I right click on the video I am able to download and I can play it using the player on my computer but I am not able to play it in my view. Also when I right click on it the options for "play", "skip", etc. are all blocked. Here is my model :

  class Video < ActiveRecord::Base
  
      has_attached_file :clip, :styles => {
  
              :medium => { :geometry => "640x480", :format => 'flv'},
  
              :thumb => {:geometry => "100x100#", :format => 'jpg', :time => 10}
  
          }, :processors => [:ffmpeg]
  
      do_not_validate_attachment_file_type(:clip)
  
  end

  And here is my view :

  <table class="table">
  
                      <tr>
  
                          <th>Video</th>
  
                          <th>Title</th>
  
                          <th>Caption</th>
  
                      </tr>
  
                      &lt;% @video.each do |video| %>
  
                          <tr>
  
                              <td>
  
                                  &lt;%= image_tag video.clip.url(:thumb) %>
  
                                  &lt;%= video_tag video.clip.url(:medium) %>
  
                              </td>
  
                              <td>
  
                                  &lt;%= label_tag video.title %>
  
                              </td>
  
                              <td>
  
                                  &lt;%= label_tag video.caption %>
  
                              </td>
  
                          </tr>
  
                      &lt;% end %>
  
                  </table>

  I have also tried using the videojs_rails gem but I wasn't able to play the video using that either. I would greatly appreciate it if someone could help me out, I've been searching for an answer everywhere but haven't come across one that has worked for me.

  Thanks in advance

• avformat/mpegtsenc : Changed Video PES packet length to 0.

  12 avril 2014, par Graham Booker

  avformat/mpegtsenc : Changed Video PES packet length to 0.
  The rational for this is another issue that plex has exposed.  When it is
  
  conducting a transcode of video to HLS for streaming, my father noticed
  
  artifacts when played on his GoogleTV (NSZ-GT1).  He sent me a test file
  
  and I reproduced it on my device of the same model.  It is important to
  
  note that the artifacts were not present when streaming to VLC or QuickTime
  
  Player.  I copied the command-line that plex used, and conducted all of the
  
  following tests using FFmpeg git.
  Transcode to HLS : artifacts on playback
  
  Transcode to TS : playback is fine
  
  Cat HLS segments into a single TS : playback is fine
  
  Segment single TS file to segments : artifacts on playback
  
  Segment single TS file to segments using Apple’s HLS segmenter : playback is
  
  fine
  At this point I carefully examined the differences between Apple’s HLS
  
  segmenter output and FFmpeg’s.  Among the considerable differences, I
  
  noticed that the video PES packets always had a 0 length.  So I continued :
  Transcode to HLS using FFmpeg with 0 length PES packets : playback is fine.
  
  Segment single TS to segments with 0 length PES packets : playback is fine.
  All failures mentioned are only on the GTV since it is the only player on
  
  which I could reproduce artifacts.  I only tested the GTV, VLC, and
  
  QuickTime Player though, so my test case is limited.  I do not know if
  
  other players exhibit this issue.
  Since it was useful last time, I have uploaded the test file as
  
  hls_pes_packet_length.m4v along with its associated txt file which contains
  
  the transcode command-line that was used.
  Reviewed-by : Kieran Kunhya <kierank@obe.tv>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/mpegtsenc.c
  • [DH] tests/ref/lavf/ts