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• opus_celt : rename structures to better names and reorganize them

  11 février 2017, par Rostislav Pehlivanov

  opus_celt : rename structures to better names and reorganize them
  This is meant to be applied on top of my previous patch which
  
  split PVQ into celt_pvq.c and made opus_celt.h
  Essentially nothing has been changed other than renaming CeltFrame
  
  to CeltBlock (CeltFrame had absolutely nothing at all to do with
  
  a frame) and CeltContext to CeltFrame.
  
  3 variables have been put in CeltFrame as they make more sense
  
  there rather than being passed around as arguments.
  
  The coefficients have been moved to the CeltBlock structure
  
  (why the hell were they in CeltContext and not in CeltFrame ??).
  Now the encoder would be able to use the exact context the decoder
  
  uses (plus a couple of extra fields in there).
  FATE passes, no slowdowns, etc.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/opus.h
  • [DH] libavcodec/opus_celt.c
  • [DH] libavcodec/opus_celt.h
  • [DH] libavcodec/opus_pvq.c
  • [DH] libavcodec/opus_pvq.h
  • [DH] libavcodec/opusdec.c
  • [DH] libavcodec/opustab.c
  • [DH] libavcodec/opustab.h

• FFMpeg is writing a matplotlib animation with diminishing quality

  3 mars 2017, par Bryan Stafford

  I am trying to create a bunch of animations that follow the paths National Hockey League teams travel during the current season. Currently, my animation looks like this.

  As you can see, the animation begins decently sharp but within 2 seconds the quality bottoms out and everything is grainy.

  The relevant code is this :

  ani = animation.FuncAnimation(fig, update, frames=len(all_x + 20), 
  
                                interval=75, repeat=False)
  
  filepath =  map_team + '.mp4'
  
  ani.save(filepath, writer='ffmpeg', fps=30)
  
  plt.tight_layout()
  
  plt.show()

  I have chosen FFMpeg as my writer because I hope to put about 30 graphics online and the MP4 format keeps each file around 1.5MB. If there’s a way to keep the graphics sharp, with low file sizes, and able to be uploaded onto Imgur, I would love to do that with my project.

  Thanks.

• Create video from images, add audio and animation within images without FFMPEG in Android

  28 février 2017, par Vivek Bhatt

  I want to create a video from multiple images without using FFMPEG in Android. Also i have to multiple audios over it. And at last there should be some animation within each images. I have tried this using FFMPEG, but it is taking hell lot of time, let say , 4-5 min for 10 photos. Is there any other way for this or any efficient way ?

  There is 3 way process.

  1. First i create video from each image with audio and added text.
  2. Then i concatenate all the videos into a single video.
  3. At last, i add a background audio to the concatenated video.

  I am sharing the commands here :

  1.
  String[] cmds = "-y"
  , "-r", "1", "-vcodec", "mjpeg" ,"-loop", "1", "-t", "1"
  , "-i", image
  , "-i", audio
  , "-vf"
  , "zoompan=z=’if(lte(zoom,1),1.1,max(1.001,zoom-0.0015))’:d=125,drawbox=y=ih/PHI:color=black@0.4:width=iw:height=120:t=max,drawtext=fontfile=/storage/emulated/0/ffmpeg/font.ttf:text="+text+":fontcolor=white:fontsize=60:x=(w-tw)/2:y=(h/PHI)+th"
  , "-c:v", "libx264"
  , "-preset", "ultrafast", "-t", "5", "-c:a", "aac", "-b:a", "128k", "-pix_fmt", "yuv420p"
  , "video1.mp4" ;

  2.

  String cmd = "-y -i video1.mp4 -i video2.mp4 -i video3.mp4 -filter_complex concat=n=3:v=1:a=1 -preset ultrafast concat_video.mp4 ;

  3.

  cmd = "-y -i bg_audio.mp3 -i concat_video.mp4 -shortest -preset ultrafast -filter_complex [a1][a2]amerge,pan=stereo:c0