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• PySceneDetect FFmpeg Not Available

  14 août 2023, par Dmitriy Pushkarev

  I already installed FFmpeg and this is available in terminal I can convert video and etc, but it's completely not available in PySceneDetect.

  


  pip installed FFmpeg-python and FFmpeg library and FFmpeg itself in system.

  


  PySceneDetect returns :

  


  ffmpeg could not be found on the system. Please install ffmpeg to enable video output support.


  


  I think trouble with path, but can't put path in PySceneDetect. I can use path to binary FFmpeg, only in ffmpeg-python library, like this and it's working

  


  This code working fine :

  


  Here i using only FFmpeg-python library

  


  stream = ffmpeg.input('vi0.mp4')
stream = ffmpeg.filter(stream, 'fps', fps=10, round='up')
stream = ffmpeg.output(stream, 'vi1.mp4')
ffmpeg.run(stream,cmd='./ffmpeg')


  


  But can't it to get work with PySceneDetect

  


  print(scenedetect.video_splitter.is_ffmpeg_available())


  


  return False

  


  split_video_ffmpeg(video_path, scene_list, show_progress=False)


  


  returns "ffmpeg could not be found on the system. Please install ffmpeg to enable video output support."

  


• How to run a video on chromium/lubuntu smoothly on a low-end machine ?

  29 juillet 2020, par Altuğ Ceylan

  the cpu of the machine is Atom X5-Z8350 with a ram size of 4 GB. It does not have an external gpu.
The problem is that when it runs a video on chromium such as a youtube video, it stutters and fps drop happens. I found out that the cpu supports h264 and vp8, and chromium only supports vp-8 and vp-9. Therefore, I used ffmpeg to transcode a video I downloaded from youtube to see if it was going to help.
I used the following script from my github repository which also contains driver update scripts etc

  


  
#$1 input filename
#$2 good realtime best
#$3 --cpu-used for best and good deadline valid values are from 0 to 5 for realtime 0 to 15
#$4 tile columns allow multi threading use powers of 2 eg 2=4
#$5 no threads to use
#$6 minrate around 2k is good for 1080p60
#$7 out filename
# -b:v bitrate 512k maybe too low for 720p30 try 1500k to 2000k 
#for fast/quality use realtime 6-7 
#for very good quality use good 2
start=$(date +%s.%N)
ffmpeg -i $1 -r 30 -g 90 -s 1280x720 -aspect 16:9 -c:v libvpx -deadline $2 -row-mt 1 -b:v 2500k -threads $5 -tile-columns $4 -cpu-used $3 -minrate $6 -bufsize 3000k -maxrate 3000k -crf 30 -frame-parallel 1 $7.webm
duration=$(echo "$(date +%s.%N) - $start" | bc)
execution_time=`printf "%.2f seconds" $duration`
echo "Script Execution Time: $execution_time"



  


  I changed crf to 5, -r to 120 -s to 1920x1080 and passed $2 as realtime, $3 as 7, $4 as 2 , $5 as 4, $6 as 2000k, I used the following video https://www.youtube.com/watch?v=jZKvJY6gDfg. It was a lot better than before, the chromium was having hard time running 720p30 but now it actually ran the 1080p120 video with minor tear and fps drops. How can I prevent the tears and the fps drops from happening ?

  


• FFmpeg(C/libav) VPX to mpeg2video stream cannot be reproduce in VLC

  21 septembre 2017, par caiomcg

  I am currently trying to transcode a VPX(VP8/VP9) video to a mpeg2video and stream it over UDP with mpegts.

  I have initialized all of the contexts and the streams and as long as I stream it to ffplay it works, if I send the stream to VLC or another player, the receiver only display the first frame and do nothing else. If I do the same thing through the command line it works flawlessly - ffmpeg -re -i video.webm -an -f mpegts udp://127.0.0.1:8080

  My output context :

  this->output_codec_ctx_->codec_type    = AVMEDIA_TYPE_VIDEO; // Set media type
  
  this->output_codec_ctx_->pix_fmt       = AV_PIX_FMT_YUV420P; // Set stream pixel format
  
  this->output_codec_ctx_->time_base.den = ceil(av_q2d(input_stream->r_frame_rate));     // Add the real video framerate. Eg.: 29.9
  
  this->output_codec_ctx_->time_base.num = 1;                  // Numerator of the framerate. Eg.: num/29.9
  
  this->output_codec_ctx_->width         = input_stream->codecpar->width;  // Video width
  
  this->output_codec_ctx_->height        = input_stream->codecpar->height; // Video height
  
  this->output_codec_ctx_->bit_rate      = 400000; // Video quality
  
  this->output_codec_ctx_->gop_size      = 12;
  
  this->output_codec_ctx_->max_b_frames  = 2;
  
  this->output_codec_ctx_->framerate     = this->input_codec_ctx_->framerate;
  
  this->output_codec_ctx_->sample_aspect_ratio     = this->input_codec_ctx_->sample_aspect_ratio;

  My av_dump :

  Output #0, mpegts, to 'udp://127.0.0.1:20010':
  
    Metadata:
  
      encoder         : Lavf57.72.101
  
      Stream #0:0: Video: mpeg2video (Main), 1 reference frame, yuv420p, 480x640 (0x0), q=2-31, 400 kb/s, SAR 1:1 DAR 3:4, 24 fps, 24 tbr, 90k tbn

  FFMPEG av_dump :

  Output #0, mpegts, to 'udp://127.0.0.1:20010':
  
    Metadata:
  
      title           : Tears of Steel
  
      encoder         : Lavf57.72.101
  
      Stream #0:0: Video: mpeg2video (Main), yuv420p, 480x640 [SAR 1:1 DAR 3:4], q=2-31, 200 kb/s, 24 fps, 90k tbn, 24 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.96.101 mpeg2video
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1

  Any ideia on what I may be doing wrong ?