Recherche avancée

Sur d’autres sites (6636)

• Creating MOV from PNGs with ffmpeg : playback issue in older quicktime (7.6.6)

  15 avril 2013, par Jim Lindstrom

  I'm using ffmpeg to create a MOV file from a series of images. When I view the movie in Quicktime 7.7.x, it looks great (left image). When I view in Quicktime 7.6.6 I get this weird issue (on the right) :

  
  

  Any idea even what this is, much less how to fix it ?

  Details

  My source images are a mix of PNGs and JPGs that I pre-process with ImageMagick (to draw text, captions, etc). I store intermediate results as MPCs, and final frames as PNMs.

  To draw the above frame, I'm doing this :

  convert -background none -fill white -font my_font.ttf -pointsize 132 -gravity \
  
          center -size 945x550 caption:"Stills Demo" background-template.png     \
  
          +swap -composite -resize 1920x1080! /tmp/title_screen4338355.png
  
  convert -auto-orient /tmp/title_screen4338355.png -resize 100% -type TrueColor \
  
          /tmp/1b2764754ce6e420986ed74b942bcf67.mpc
  
  convert /tmp/1b2764754ce6e420986ed74b942bcf67.mpc -set option:distort:viewport \
  
          1920x1080+0+0  +distort SRT '960.0,540.0 1.0 0 960.0,540.0'            \
  
          /tmp/stills-project-6224/video_frames/img_0000.pnm

  I render frames with ffmpeg like so :

  ffmpeg -y -f image2 -i /tmp/stills-project-6224/video_frames/img_%04d.pnm      \
  
         -i /tmp/soundtrack_8702693.wav -vcodec libx264 -pix_fmt yuvj444p        \
  
         -b:v 2200k  -r 25 -strict experimental                                  \
  
         /tmp/stills-project-6224/video_rendered/output.mov

  The rest of the video is fine. The other images are photos (jpgs or pngs) that I process in the same way. I have also noticed that if I don't apply text to this background-template, the image shows up fine, so I think the issue has something to do with either how I'm processing or saving that image.

• How do I alter my FFMPEG command to make my HTTP Live Streams more efficient ?

  17 octobre 2014, par Robert

  I want to reduce the muxing overhead when creating .ts files using FFMPEG.

  Im using FFMPEG to create a series of transport stream files used for HTTP live streaming.

  ./ffmpeg -i myInputFile.ismv \
  
           -vcodec copy \
  
           -acodec copy \
  
           -bsf h264_mp4toannexb \
  
           -map 0 \
  
           -f segment \
  
           -segment_time 10\
  
           -segment_list_size 999999 \
  
           -segment_list output/myVarientPlaylist.m3u8 \
  
           -segment_format mpegts \
  
           output/myAudioVideoFile-%04d.ts

  My input is in ismv format and contains a video and audio stream :

  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x240, 348 kb/s, 29.97 tbr, 10000k tbn, 59.94 tbc
  
  Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 63 kb/s

  There is an issues related to muxing that is causing a large amout of overhead to be added to the streams. This is how the issue was described to me for the audio :

  

  So for a given aac stream, the overhead will be 88% (since 200 bytes will map to 2 x 188 byte packets).

  For video, the iframe packets are quite large, so they translate nicely into .ts packets, however, the diffs can be as small as an audio packet, therefore they suffer from the same issue.

  The solution is to combine several aac packets into one larger stream before packaging them into .ts. Is this possible out of the box with FFMPEG ?

• FFMpeg Commands definition in library source code

  25 janvier 2013, par SKC

  I tried running the ffmpeg commands from Android activity using an emulator in Windows OS, but i get errors.
  I tried keeping both my resource files in /mnt/sdcard as well the application package within /data/data, but none of the options worked out for running the ffmpeg commands.

  These are the following approach i had taken while running the command through an android activity.
  (Command to convert a series if images into a video)
  Approach 1 :

      String[] cmd =new String[4];
  
      cmd[0]="/data/data/com.example.commandlineffmpeg/files/ffmpeg";
  
      cmd[1]="-i";
  
      cmd[2]="/data/data/com.example.commandlineffmpeg/images/bpc_%03d.png";
  
      cmd[3]="/data/data/com.example.commandlineffmpeg/out/out.avi";
  
  
  
      Process p = Runtime.getRuntime().exec(cmd, null, new File("/data/data/com.example.ffmpegnew/out"));

  I have solved this, basically there was system permission issues and hence we were not allowed to access the system properties required to run the FFMpeg commands.
  Thus we need to sign the apps with the system certificates and hence we can use FFMpeg commands directly from any android activity.