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• command line closes too fast inside python using ffmpeg

  18 février 2014, par user3012914

  I am using python to create a Macro Module inside MevisLab environment. I wanted to use ffmpeg in command prompt inside Python. The Problem is the command prompt closes too fast that i couldnt read while executing ffmpeg.

  My code

    t = 'ffmpeg -r'+str(ctx.field("FrameRate").value)+'-f image2 -pix_fmt yuv44p -s 1920x1080 -i'+path+'%0d.png -vodec libx264 -crf 15'+path+'.mp4'
  
  
  
  os.system(t)

• Python SWIG bindings with SomeType ** as function argument

  2 mai 2013, par vericule

  I couldn't find any working Python bindings for ffmpeg, so I decided to generate one with SWIG. Generation was quick and easy (no customization, just default SWIG interface), but these a problem using some functions like int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options); from libavformat/avformat.h. Using C this can be run simply by :

  AVFormatContext *pFormatCtx = NULL;
  
  int status;
  
  status = avformat_open_input(&pFormatCtx, '/path/to/my/file.ext', NULL, NULL);

  In Python I try following :

  >>> from ppmpeg import *
  
  >>> av_register_all()
  
  >>> FormatCtx = AVFormatContext()
  
  >>> FormatCtx
  
   >
  
  >>> avformat_open_input(FormatCtx, '/path/to/my/file.ext', None, None)
  
  Traceback (most recent call last):
  
     File "<stdin>", line 1, in <module>
  
  TypeError: in method &#39;avformat_open_input&#39;, argument 1 of type &#39;AVFormatContext **&#39;
  
  </module></stdin>

  Problem is that Python do not have & equivalent. I tried to use cpointer.i and its pointer_class (%pointer_class(AVFormatContext, new_ctx)), but new_ctx() returns pointer and this is not I want definitely. %pointer_class(AVFormatContext *, new_ctx) is illegal and gives syntax error. I would be grateful for any help. Thanks.

  EDIT :
  I forgot to mention I tried to use typemaps, but don't know how to write custom typemap for struct and documentation has only examples for basic types like int or float...

• FFmpeg returning an error - What does it mean ?

  19 mars 2013, par user1031947

  I am using FFmpeg, libmp3lame & libx264 along with the node fluent-ffmpeg module. This is my first foray into processing uploaded videos.

  From node, I use the following code to process an uploaded video :

  var proc = new ffmpeg({ source: src, nolog: true })
  
      .usingPreset( "podcast" )
  
      .withAudioCodec( "libmp3lame" )
  
      .saveToFile( dest, function( retcode, err ){
  
           if( err ) throw err;
  
           ...
  
      });

  When I try to process a video, this fails with the following error, which I don't understand. I am hoping someone here can help point me in the right direction. Thanks !

  > ffmpeg version 0.8.5-6:0.8.5-1, Copyright (c) 2000-2012 the Libav
  
  > developers   built on Jan 13 2013 12:05:48 with gcc 4.7.2
  
  > *** THIS PROGRAM IS DEPRECATED *** This program is only provided for compatibility and will be removed in a future release. Please use
  
  > avconv instead.
  
  > 
  
  > Seems stream 0 codec frame rate differs from container frame rate:
  
  > 5994.00 (5994/1) -> 29.97 (2997/100) Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
  
  > '/home/ssp/resources/tmp/32111bf4217e87c23328ec81c56c7d02':  
  
  > Metadata:
  
  >     major_brand     : M4VP
  
  >     minor_version   : 1
  
  >     compatible_brands: M4VPM4A mp42isom
  
  >     creation_time   : 2008-08-26 17:28:47   Duration: 00:00:08.01, start: 0.000000, bitrate: 944 kb/s
  
  >     Stream #0.0(eng): Video: h264 (Constrained Baseline), yuv420p, 480x272, 815 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 5994 tbc
  
  >     Metadata:
  
  >       creation_time   : 2008-08-26 17:28:47
  
  >     Stream #0.1(eng): Audio: aac, 44100 Hz, stereo, s16, 124 kb/s
  
  >     Metadata:
  
  >       creation_time   : 2008-08-26 17:28:47 [buffer @ 0xb685a0] w:480 h:272 pixfmt:yuv420p [scale @ 0xb63280] w:480 h:272 fmt:yuv420p ->
  
  > w:320 h:176 fmt:yuv420p flags:0x4 [libx264 @ 0xb67c20] VBV maxrate
  
  > unspecified, assuming CBR [libx264 @ 0xb67c20] using cpu capabilities:
  
  > MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX [libx264 @ 0xb67c20]
  
  > profile Main, level 1.3 Output #0, m4v, to
  
  > '/home/ssp/resources/users/11/026468c8f4ea1beee0a585ebc2208137.m4v':  
  
  > Metadata:
  
  >     major_brand     : M4VP
  
  >     minor_version   : 1
  
  >     compatible_brands: M4VPM4A mp42isom
  
  >     creation_time   : 2008-08-26 17:28:47
  
  >     encoder         : Lavf53.21.1
  
  >     Stream #0.0(eng): Video: libx264, yuv420p, 320x176, q=10-51, 512 kb/s, 90k tbn, 29.97 tbc
  
  >     Metadata:
  
  >       creation_time   : 2008-08-26 17:28:47
  
  >     Stream #0.1(eng): Audio: libmp3lame, 44100 Hz, 1 channels, s16, 128 kb/s
  
  >     Metadata:
  
  >       creation_time   : 2008-08-26 17:28:47 Stream mapping:   Stream #0.0 -> #0.0   Stream #0.1 -> #0.1 Press ctrl-c to stop encoding frame=  240 fps=154 q=11.0 Lsize=     642kB time=7.97 bitrate=
  
  > 659.3kbits/s     video:516kB audio:126kB global headers:0kB muxing overhead 0.000000% frame I:1     Avg QP:15.35  size:  9995 [libx264 @
  
  > 0xb67c20] frame P:77    Avg QP:13.25  size:  5419 [libx264 @ 0xb67c20]
  
  > frame B:162   Avg QP:18.31  size:   625 [libx264 @ 0xb67c20]
  
  > consecutive B-frames:  2.5% 12.5% 30.0% 55.0% [libx264 @ 0xb67c20] mb
  
  > I  I16..4:  9.1%  0.0% 90.9% [libx264 @ 0xb67c20] mb P  I16..4:  2.1% 
  
  > 0.0%  2.8%  P16..4: 18.0% 29.9% 44.8%  0.0%  0.0%    skip: 2.3% [libx264 @ 0xb67c20] mb B  I16..4:  0.1%  0.0%  0.0%  B16..8: 35.2%
  
  > 20.2%  1.9%  direct:14.5%  skip:28.1%  L0:26.3% L1:38.1% BI:35.6% [libx264 @ 0xb67c20] coded y,uvDC,uvAC intra: 83.7% 91.7% 84.7% inter:
  
  > 27.7% 43.4% 13.9% [libx264 @ 0xb67c20] i16 v,h,dc,p: 20% 29% 42%  9% [libx264 @ 0xb67c20] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 29% 20%  4% 
  
  > 8%  6%  9%  3%  4% [libx264 @ 0xb67c20] i8c dc,h,v,p: 60% 19% 16%  5%
  
  > [libx264 @ 0xb67c20] Weighted P-Frames: Y:2.6% UV:0.0% [libx264 @
  
  > 0xb67c20] ref P L0: 75.6% 13.5%  8.0%  2.8%  0.1% [libx264 @ 0xb67c20]
  
  > ref B L0: 94.5%  5.5% [libx264 @ 0xb67c20] kb/s:528.00