Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
MPEG_STAT(1)		    General Commands Manual		  MPEG_STAT(1)

NAME
       mpeg_stat - analyzes MPEG-1 encoded bitstreams

SYNOPSIS
       mpeg_stat  [ -all basename ] [ -block_info filename ] [ -dct ] [	-end N
       ] [ -histogram filename ] [ -offsets filename ] [ -qscale filename ]  [
       -quiet  ]  [ -rate filename ] [ -ratelength N ] [ -time ] [ -size file-
       name ] [	-start N ] [ -syslog filename ]	[ -userdata filename ] [ -ver-
       ify ] [ file_name ]

DESCRIPTION
       mpeg_stat  decodes mpeg-1 encoded bitstreams collecting varying amounts
       of statistics.  Errors are sent to stderr, basic	statistics to  stdout.
       The  basic  information	is the pattern of frames used, number of bytes
       for each	frame type, the	specified parameters, and lengths of  vectors.
       For  each frame type, the average size, compression rate, Q-factor, and
       time to decode are given.  Wherever a filename is requested  -  can  be
       used to denote stdin/out.

OPTIONS
       -all   basename	 :  records  information  from	all  options  (qscale,
	      block_info, etc.)	into files with	 basenames  of	basename  (For
	      wizards,	-all  foo  -block_info bar will	record all options BUT
	      -block_info into files of	the form foo.*).

       -block_info filename : records information about	every block into  file
	      filename.	  Useful  for  detailed	analysis and to	make specifics
	      files for	re-encoding (see block2spec).  The format is:

	      frame frame# IPB-type mv-scale temporal_ref

	      slice slice# q-scale

	      block block# IPB-type Q-scale bits  block-type  <vectors-if-any>
		     <cbp> <dct	decode>
       Numbering  starts  at  0	 (except slices) and all motion	vectors	are in
       half-pel	units <X Y>.

       -dct : enables the decoded dct values to	be output into the block file.

       -end N :	causes mpeg_stat to finish collecting statistics at frame N.

       -histogram filename : summaries the overall statisitcs for  each	 frame
	      type into	the file.

       -offsets	 filename : record the offset of every picture,	GOP, and slice
	      into file	filename.

       -quiet :	toggles	the display of the frame-types as they are parsed (and
	      custom quantization matrices) [default: on].

       -qscale	filename  : writes Q factor and	custom quantization matrix in-
	      formation	into file filename.  The Q-factor and number of	blocks
	      of that quality (ignoring	skipped	blocks)	for each type of frame
	      is recorded.

       -rate filename :	record the bit rate at every picture (after the	 first
	      second)  into the	file filename.	Also collect minimum and maxi-
	      mum bit rate encountered in the summary information.   (Rate  is
	      the number of bits used per second, at every frame).

       -ratelength N : Change the measurement period for rate to N, so it will
	      measure the total	rate required over any N frame	period	(after
	      the first	N, of course).

       -size  filename : stores	information about the type (I,P,B) and size of
	      each frame in file filename (one frame per line).

       -start N	: causes mpeg_stat to begin collecting statistics at frame  N.
	      (Preceding  frames  will	be parsed, but few statistics are col-
	      lected (the system layer counters	will sill be running).)	 -sys-
	      log  filename  :	describes the parsing of the system layer into
	      the file filename.  Note this option is not turned on  by	 -all.
	      -time : prints the amount	of time	total and per-frame type aver-
	      ages to decode.  This will give an estimate of time in  a	 soft-
	      ware  player,  but  is not generally useful, so it is off	by de-
	      fault.  -userdata	filename : dumps user data fields into a file.
	      Can be read in ASCII.  -verify : does more work to check the va-
	      lidity of	the sequence.  Slows down the statistics, so it	is op-
	      tional.

EXAMPLE
       Decoding	the flowergarden sequence (mpeg_stat -quiet flower.mpg)	should
       produce the following statistics:

       Reading /u/smoot/mpg/flower.mpg

       Frame  sequence	as  to	be  displayed:	 BBPBBPBBPBBPBBIBBPBBPBBPBBPB-
       BIBBPBBPBBPBBPBBIBBPBBPBBPBBPBBIBBPBBPBBPBBPBBI		BBPBBPBBPBBPB-
       BIBBPBBPBBPBBPBBIBBPBBPBBPBBPBBIBBPBBPBBPBBPBBIBBPBBPBBPBBPBB

       Searching  for  constant	 frame	 type	sequence...pattern   detected:
       IBBPBBPBBPBBPBB

       SUMMARY:

       Total Bytes read: 0. Total number of frames: 150.  Length is 5.01 sec

       Width:  352	Height:	240 Avg. Frame Size: 4786 bytes	+ 6 bits  (av-
       erage rate 1147692.76 bits/sec)

       Total Compression Rate:	1.89 % of uncompressed 24 bit images
			       =  0.45 bits per	pixel

       Number of Macroblocks [width * height = sum]: 22	x 15 = 330  per	 frame
       Skipped Macroblocks = 4389 (9.46%), Coded Macroblocks = 41992 (90.54%)

       Total Time Decoding: 8.611 secs.	0.05721	sec/frame or 17.11 frames/sec.

       MPEG-Viewer requirements:
	       Pixel aspect ratio of 0.6735
	       Required	display	speed: 29.97 frames/sec
	       Specified bit rate is 1.00 MBits/sec (2500 * 400bits/sec)
	       Requested buffer	size is	8K ints	(16 bits).
	       And  the	 constrained  parameter	 flag  is on.	    The	stream
       meets the constrained parameter requirements.

       Length of vectors in pixels:
	       Horizontal forward vectors, maximum :  39       average:	  6
	       Vertical	forward	vectors, maximum   :  22       average:	  1

	       Horizontal backward vectors, maximum:  29       average:	  5
	       Vertical	backward vectors, maximum  :  16       average:	  1

       Frame specific information:

	   10  I FRAMES, average is:
	       Size: 17323 bytes + 1 bits (24.13%)
	       Compression Rate:  6.84%
	       Q Factor	[scales	quantization matrix]: 11.15
	       Time to Decode: 0.114039	secs.

	   40  P FRAMES, average is:
	       Size: 8031 bytes	+ 0 bits (44.74%)
	       Compression Rate:  3.17%
	       Q Factor	[scales	quantization matrix]: 10.85
	       Time to Decode: 0.075342	secs.

	   100 B FRAMES, average is:
	       Size: 2235 bytes	+ 4 bits (31.13%)
	       Compression Rate:  0.88%
	       Q Factor	[scales	quantization matrix]: 15.01
	       50.59% interpolated Macro Blocks
	       Time to Decode: 0.044516	secs.

NOTES
       The analyzer expects MPEG-1 video streams only. It  can	handle	multi-
       plexed  MPEG  streams  (video+audio  streams),  but mostly analyzes the
       video portion.

       Some streams do not end with the	proper	sequence  end  code  and  will
       probably	generate an "Improper sequence end code." error	when done.  In
       general mpeg_stat attempts to catch and alert its user to errors	in the
       stream.	 Such errors are glossed over in mpeg_play.  Be	aware that er-
       rors can	disturb	statistics gathering, generating odd results.

       This player can handle XING data	files. Be aware	that XING makes	no use
       of  temporal  redundancy	 or motion vector information. In other	words,
       they do not use any P or	B frames in their streams. Instead, XING  data
       is simply a sequence of I frames.

HISTORY
       The  analyzer is	based on the UC	Berkeley mpeg_play player by Ketan Pa-
       tel, Brian Smith, Henry Chi-To Ma, and Kim Man Liu.  It was modified at
       the  Technical University of Berlin, Germany, Dept. of Computer Science
       by Tom Pfeifer, Jens Brettin, Harald  Masche,  Alexander	 Schulze,  and
       Dirk  Schubert.	 It has	been further modified to collect much more in-
       formation by Steve Smoot	(UC Berkeley).

BUGS
       No statistics should be collected before	the  start  frame.   Sometimes
       system  layer  streams  will  indicate that they	lack proper end	codes,
       when they have them.  VBV size conformance is not  checked.   Verifica-
       tion is not complete.  Frame numbers should probably be in display num-
       bering not stream numbering.  Other bugs?  Send mail to <mpeg-bugs@pla-
       teau.cs.berkeley.edu>.

VERSION
       This is version 2.2, contining some new features	since 2.1, and several
       bug fixes.  It is a major change	since version 1.0.

AUTHORS
       Ketan Patel -  University  of  California,  Berkeley,  kpatel@cs.berke-
	      ley.edu

       Brian  Smith  -	University  of	California, Berkeley, bsmith@cs.berke-
	      ley.edu

       Henry Chi-To Ma - University  of	 California,  Berkeley,	 cma@cs.berke-
	      ley.edu

       Kim Man Liu - University	of California, Berkeley, kliu@cs.berkeley.edu

       Tom Pfeifer - Multimedia	systems	project	- pfeifer@fokus.gmd.de

       Steve Smoot - University	of California, Berkeley, smoot@cs.berkeley.edu

				1 December 1994			  MPEG_STAT(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLE | NOTES | HISTORY | BUGS | VERSION | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=mpeg_stat&sektion=1&manpath=FreeBSD+12.2-RELEASE+and+Ports>

home | help