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• Ubuntu reduce video size with ffmepg and change format

  27 juillet 2015, par Arnas Pečelis

  I want to watermark, reduce weigth, resize and change format for selected videos.
  Also I need to keep quality as high as it possible.

  Now what I have :

  ffmpeg -i prepared/video.mp4 -i units/video_watermark.png -filter_complex overlay=10:10 -codec:a copy moved/video_test.mp4

  and I’m watermarking video, but the quality drops a lot. Also I have :

  ffmpeg -i prepared/video.mp4 -s 1280x720 -b 512k -vcodec mpeg1video -acodec copy

  but also I need to reduce weight also as lot as possible. The reconstructed videos will be shown as movies online. My question would be - is it possible to do it one line and change format to .mp4 ?

  PS. I have constructed command :

  ffmpeg -i downloaded/movie/movie.avi -c:v libx264 -acodec libfaac -b:a 64k -preset ultrafast -vf "movie=units/video_watermark.png [watermark]; [in][watermark] overlay=10:10 [out]" -movflags faststart prepared/movie.mp4

  but it returns me error :

  ffmpeg version 2.7.1 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
  
    configuration:
  
    libavutil      54. 27.100 / 54. 27.100
  
    libavcodec     56. 41.100 / 56. 41.100
  
    libavformat    56. 36.100 / 56. 36.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 16.101 /  5. 16.101
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.100 /  1.  2.100
  
  Unrecognized option 'preset'.
  
  Error splitting the argument list: Option not found

• Problems loading G.729 decoder with FFmpeg API

  20 juillet 2015, par gapc

  I built a class with the use of the FFmpeg API to decode several audio files (mp3, ogg, G.729, etc) and load them into a data structure as raw audio data. Now for example when I run the following code :

  codec = avcodec_find_decoder(AV_CODEC_ID_G729);
  
  if (codec == NULL){
  
      printf("Codec not found");
  
      exit(1);
  
  }

  The program will indeed output the error message, but if I load mp3 or ogg codecs there’s no issue.

  So to double check I executed in the terminal ffmpeg -decoders to see if the decoder is supported (which I also checked online) and outputs :

  A....D g729                 G.729

  I need the decoder for G.729. Is there anything I’m missing or doing something wrong ? Is there a different way to load this decoder ? Any suggestions would be greatly appreciated.

  The FFmpeg version installed is 2.7.1 on a Debian system

  API use example : https://www.ffmpeg.org/doxygen/2.7/decoding_encoding_8c-example.html

• Using ffmpeg ffprobe with Visual C++

  11 juillet 2015, par astracat111

  I have the following command line that gives me the duration of a video file :

  ffprobe.exe -i Video.mp4 show_entries format=duration -v quiet -of csv="p=0"

  When I run this, I get back the duration of my video successfully, running it from a command prompt. Now, I’m kind of a beginner with C++, so I’m not sure how I could get that duration to be put into a float inside of my program. I’ve looked through a lot of articles and question and answer forums online and I’ve found possible answers with...using stdout/stdin to grab the information...? I’m not sure.

  My strategy right now is to use CreateProcess() to run the process, then WaitForSingleObject(), then somehow use some command to grab the output data from the ffprobe process. Perhaps the data I’m looking for can be retrieved through the CreateProcess() function ? I feel like I’m very close, but I’m in serious need of help with this...

  As a side note, since I’m using Visual C++ Express 2010, I do not have access to MFC.

  If anyone could lead me in the right direction to this information it would be greatly appreciated.