[FFmpeg-trac] #678(undetermined:new): Warn that filtering is disabled when copying streams

[FFmpeg]

#678: Warn that filtering is disabled when copying streams
-------------------------------------+-------------------------------------
               Reporter:  llogan     |                  Owner:
                   Type:             |                 Status:  new
  enhancement                        |              Component:
               Priority:  wish       |  undetermined
                Version:  git-       |               Keywords:
  master                             |               Blocking:
             Blocked By:             |  Analyzed by developer:  0
Reproduced by developer:  0          |
-------------------------------------+-------------------------------------
 Some users assume they can copy a video steam and perform filtering [1].
 FFmpeg does not give any feedback that the filter is being ignored.

 Current behavior:
 {{{
 $ ffmpeg -i hop.mp4 -c copy -vf crop=iw:ih-20 -y out.mpg
 ffmpeg version N-35078-g7831788, Copyright (c) 2000-2011 the FFmpeg
 developers
   built on Nov 22 2011 10:36:32 with gcc 4.6.2
   configuration: --prefix=/usr --enable-gpl
   libavutil    51. 26. 0 / 51. 26. 0
   libavcodec   53. 36. 0 / 53. 36. 0
   libavformat  53. 21. 0 / 53. 21. 0
   libavdevice  53.  4. 0 / 53.  4. 0
   libavfilter   2. 49. 0 /  2. 49. 0
   libswscale    2.  1. 0 /  2.  1. 0
   libpostproc  51.  2. 0 / 51.  2. 0
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'hop.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     creation_time   : 1970-01-01 00:00:00
     encoder         : Lavf52.32.0
   Duration: 00:00:10.13, start: 0.000000, bitrate: 563 kb/s
     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
 640x480, 559 kb/s, 30 fps, 30 tbr, 30 tbn, 60 tbc
     Metadata:
       creation_time   : 1970-01-01 00:00:00
       handler_name    :
 [mpeg @ 0x1d17860] VBV buffer size not set, muxing may fail
 Output #0, mpeg, to 'out.mpg':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     creation_time   : 1970-01-01 00:00:00
     encoder         : Lavf53.21.0
     Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p, 640x480,
 q=2-31, 559 kb/s, 30 fps, 90k tbn, 30 tbc
     Metadata:
       creation_time   : 1970-01-01 00:00:00
       handler_name    :
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
 Press [q] to stop, [?] for help
 frame=  304 fps=  0 q=-1.0 Lsize=     700kB time=00:00:10.06 bitrate=
 569.6kbits/s
 video:692kB audio:0kB global headers:0kB muxing overhead 1.166920%
 }}}

 Example warning: "Filtering is disabled when copying streams."

 Of course the message could be more specific as to what streams are
 affected and what filters are actually disabled.

 [1] http://ffmpeg.org/pipermail/ffmpeg-user/2011-November/003175.html

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/678>
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