using FFMPEG commands , can i get the default values of any media file, like resolution, audio codec, video codec..etc

like for eg. if i enter the outp开发者_如何学Cut extension '.avi' , i should get the default audio codec used , default video codec used , etc... Is there a command for this ?

I presume you mean the libavcodec API that the ffmpeg project make available?

void avcodec_get_context_defaults(AVCodecContext *s); is probably the function you want. If you mean the ffmpeg binary, that would be a better question for superuser.

Just take a stab here; you would need to declare a codec context and retrieve it from the video stream.

Did you try ffmpeg -i [FILE_NAME]? The Stream #0.0 line will give you the file metadata information. See sample below:

$ ffmpeg -i file.asf
FFmpeg version SVN-r18725, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --enable-libmp3lame --disable-mmx --enable-nonfree
  libavutil     50. 3. 0 / 50. 3. 0
  libavcodec    52.28. 0 / 52.28. 0
  libavformat   52.32. 0 / 52.32. 0
  libavdevice   52. 2. 0 / 52. 2. 0
  libswscale     0. 7. 1 /  0. 7. 1
  built on May  1 2009 10:33:46, gcc: 4.3.2

Seems stream 0 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 14.99 (15000/1001)
Input #0, asf, from 'ZAMYjD41wOjJzpJK2Lk8.asf':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0.0: Video: mpeg4, yuv420p, 640x480, 14.99 tbr, 1k tbn, 1k tbc
At least one output file must be specified