[MPlayer-DOCS] CVS: main/DOCS/man/en mplayer.1,1.856,1.857

[Loren Merritt CVS]

CVS change done by Loren Merritt CVS

Update of /cvsroot/mplayer/main/DOCS/man/en
In directory mail:/var2/tmp/cvs-serv20082

Modified Files:
	mplayer.1 
Log Message:
more on H.264's quantization parameter


Index: mplayer.1
===================================================================
RCS file: /cvsroot/mplayer/main/DOCS/man/en/mplayer.1,v
retrieving revision 1.856
retrieving revision 1.857
diff -u -r1.856 -r1.857
--- mplayer.1	13 Jan 2005 19:06:14 -0000	1.856
+++ mplayer.1	13 Jan 2005 20:13:00 -0000	1.857
@@ -7062,11 +7062,10 @@
 I- and B-frames are offset from this value by ip_factor and pb_factor, respectively.
 20\-40 is a useful range (default: 26).
 Lower values result in better fidelity, but higher bitrates.
-Note that quantization in H.264 works differently from MPEG-1/2/4.
+Note that quantization in H.264 works differently from MPEG-1/2/4:
 H.264's quantization parameter (QP) is on a logarithmic scale.
-As an example, the bitrate difference between QP=20 and QP=40
-is about a factor of 10.
-Useful quantizers in H.264 tend to be very large compared to MPEG-1/2/4.
+The mapping is approximately H264QP = 12 + 6*log2(MPEGQP).
+For example, MPEG at QP=2 is equivalent to H.264 at QP=18.
 .
 .TP
 .B pass=<1\-3>