[MPlayer-users] -identify

matt ittigson ittigson at pobox.com
Fri Mar 7 22:57:33 CET 2003

i'm interested in using mplayer as a means of gathering file
attributes about movies.  the -identify flag is pretty much perfect
for what i'm looking for.  my question relates to exactly what some of
the fields mean.

i have a file with an mpg extension.  calling identify, i get possibly
three responses to the question of, "what kind of file is this?"

first is the demuxer deciding and reporting that it's an MPEG-PS file
(what does that mean?) in demux_open_stream.  in the next line of the
-identify output it's described as MPEG1 (in video_read_properties).
then the ID_VIDEO_FORMAT field reports that it's 0x10000001.  which
should i take as the general video format (for a non-mplayer
classification of that video)?

then there's the ID_VIDEO_ASPECT field.  in this same mpg, where the
aspect is described as 12 in the video_read_properties call it's
reported as 1.3333 in the identify code.

finally, on the audio side.  the ID_AUDIO_CODEC is described as mp3.
the ID_AUDIO_FORMAT is described as 80.  and there's a whole mess of
information printed out above while the audio codec is being
initialized (in init_best_audio_codec).

thanks for your help in describing these differences.  also, if anyone
has a suggestion for better or more general ways i could be using
mplayer to accomplish my task i appreciate it.  also, how "static" are
these descriptive and codec related names?  if i relied on mplayer as
my "namer" for this project, is there any likelihood that, for
instance, today's MPEG-PS would be something else tomorrow?

verna: come on, tom, you know me a little.      ~    matt ittigson
tom: nobody knows anybody--not that well.	~
verna: you know or you wouldn't be here.	~    ittigson at pobox.com
      - miller's crossing			~

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