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• How to implement a command line of ffmpeg with ffmpeg static lib ?

  19 novembre 2014, par JackPearse

  I need a simple ffmpeg conversion task to be done inside an application :

  ffmpeg -i input_file.m4v -vcodec copy -acodec copy -vbsf h264_mp4toannexb output_file.ts

  This works well using the terminal. I’ve successfully compiled ffmpeg’s static lib. Some examples work perfectly, that means the lib is working. How do I implement the behaviour of the above command line with this library ?

  I looked into ffmpeg.c. But there is so much code inside that it took me hours to get an idea on how it works. Finally I still don’t really understand the whole structure.

  I would be very happy if someone could help me understanding how to use the library to do the very same what the example command line does. (At the end I just want to transmux mp4 files to ts files without reencoding)

  Thanks in advance

  Jack

• ffmpeg set buf_len

  2 avril 2013, par Jeetendra_Nath_Jha

  I have been taken input from the device file /dev/video49.

  using ffmpeg, following command writing from the terminal :

  ffmpeg -f video4linux2 -i /dev/video49 -target ntsc-vcd -s 1920x1080 pixfmt:yuv420p -vstats -bufsize 225k -an -f mpegts -vcodec mpeg4 udp://127.0.0.1:10000?pkt_size=1316

  but it gives an error given below :

  ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Mar 20 2013 15:06:14 with gcc 4.4.3 (Ubuntu 4.4.3-4ubuntu5.1)
  
    configuration: 
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
  [video4linux2,v4l2 @ 0x95862a0] buf_len[0] = 1048576 < expected frame size 3110400
  
  /dev/video49: Cannot allocate memory

  I don't know how to set the buf_len here...

  because in an error it says that the buf_len is need to be set.

• Python : Matplotlib Animation FFmpeg, RuntimeError : No MovieWriters available

  10 décembre 2017, par ib-

  The problem I am getting is in code similar to this example :
  https://matplotlib.org/examples/animation/basic_example_writer.html

  The error :

  RuntimeError : No MovieWriters available occurs at Writer = animation.writers['ffmpeg'] in the example above.

  I am using mac, I have installed ffmpeg using brew, and even installed it with conda even though I am not using anaconda for this particular code.

  I am positive that it is installed - I have used it in terminal to change files but it is not working within the program.

  Thanks !