x264: group together the primary ratecontrol options. misc clarifications.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@14309 b3059339-0415-0410-9bf9-f77b7e298cf2

1 files changed, 73 insertions, 66 deletions

diff --git a/DOCS/man/en/mplayer.1 b/DOCS/man/en/mplayer.1
index 89a9c861f8..1ee57f396b 100644
--- a/DOCS/man/en/mplayer.1
+++ b/DOCS/man/en/mplayer.1
@@ -7068,6 +7068,66 @@ Sets the bitrate to be used in kbits/\:second (default: off).
 This is required if you want a CBR (constant bitrate) encode.
 .
 .TP
+.B qp_constant=<1\-51>
+This selects the quantizer to use for P-frames.
+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[124].
+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[124].
+.
+.TP
+.B pass=<1\-3>
+Enable 2 or 3-pass mode.
+It is recommended to always encode in 2 or 3-pass mode as it leads to a
+better bit distribution and improves overall quality.
+.PD 0
+.RSs
+.IPs 1
+first pass
+.IPs 2
+second pass (of two pass encoding)
+.IPs 3
+Nth pass (second and third passes of three pass encoding)
+.RE
+.RS
+Here is how it works, and how to use it:
+.br
+The first pass (pass=1) collects statistics on the video and writes them
+to a file.
+You might want to deactivate some CPU-hungry options, apart from the ones
+that are on by default.
+.br
+In two pass mode, the second pass (pass=2) reads the stats file and
+bases ratecontrol decisions on it.
+.br
+In three pass mode, the second pass (pass=3, that is not a typo)
+does both: It first reads the stats, then overwrites them.
+You might want to backup divx2pass.log before doing this if there is
+any possibility that you will have to cancel MEncoder.
+You can use all encoding options, except very CPU-hungry options.
+.br
+The third pass (pass=3) is the same as the second pass, except that it has
+the second pass' stats to work from.
+You can use all encoding options, including CPU-hungry ones.
+.br
+The first pass may use either constant bitrate or constant quantizer.
+Constant quantizer is often slightly better, but requires that you guess a
+qp_constant that is somewhere near your desired bitrate.
+(It is better to err on the side of lower qp_constant, i.e. higher bitrate.)
+Subsequent passes are ABR, and must specify bitrate.
+.br
+.I
+NOTE:
+x264 three pass support being quite recent in MEncoder, we welcome any
+feedback you could give us on good combinations of x264 options that are
+both fast and provide good quality.
+.REss
+.
+.TP
 .B keyint=<value>
 Sets maximum interval between I-frames.
 Larger values save bits, thus improve quality, at the cost of seeking
@@ -7157,37 +7217,26 @@ directly affect distortion.
 .REss
 .
 .TP
-.B qp_constant=<1\-51>
-This selects the quantizer to use.
-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[124].
-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[124].
-.
-.TP
 .B qp_min=<1\-51> (CBR or 2 pass)
-Minimum quantizer, 15\-35 seems to be a useful range (default: 10).
+Minimum quantizer, 10\-35 seems to be a useful range (default: 10).
 .
 .TP
 .B qp_max=<1\-51> (CBR or 2 pass)
 maximum quantizer (default: 51)
 .
 .TP
-.B qp_step=<value>
+.B qp_step=<1\-50> (CBR or 2 pass)
 Maximum Value by which the quantizer may be incremented/decremented between
-frames.
+frames (default: 1).
 .
 .TP
-.B rc_buffer_size=<value>
-ratecontrol buffer size (default: 1 second's worth at the bitrate you
+.B rc_buffer_size=<value> (CBR or 2 pass)
+ratecontrol buffer size, in kbit (default: 1 second's worth at the bitrate you
 specified)
 .
 .TP
-.B rc_init_buffer=<value>
-Set the initial ratecontrol buffer (default: 1/4 of rc_buffer_size)
+.B rc_init_buffer=<0.0\-1.0> (CBR only)
+Set the initial ratecontrol buffer fullness (default: 0.25).
 .
 .TP
 .B rc_sens=<0\-100> (CBR only)
@@ -7202,56 +7251,13 @@ quantizer factor between I- and P-frames (default: 1.4)
 quantizer factor between P- and B-frames (default: 1.3)
 .
 .TP
-.B pass=<1\-3>
-Enable 2 or 3-pass mode.
-It is recommended to always encode in 2 or 3-pass mode as it leads to a
-better bit distribution and improves overall quality.
-.PD 0
-.RSs
-.IPs 1
-first pass
-.IPs 2
-second pass
-.IPs 3
-Nth pass (second and third passes of three pass encoding)
-.RE
-.RS
-Here is how it works, and how to use it:
-.br
-The first pass (pass=1) collects statistics on the video and writes them
-to a file.
-You might want to deactivate some CPU-hungry options, apart from the ones
-that are on by default.
-.br
-In two pass mode, the second pass (pass=2) reads the stats file and
-bases ratecontrol decisions on it.
-.br
-In three pass mode, the second pass (pass=3, that is not a typo)
-does both: It first reads the stats, then overwrites them.
-You might want to backup divx2pass.log before doing this if there is
-any possibility that you will have to cancel MEncoder.
-You can use all encoding options, except very CPU-hungry options.
-.br
-The third pass (pass=3) is the same as the second pass, except that it has
-the second pass' stats to work from.
-You can use all encoding options, including CPU-hungry ones.
-.br
-.I
-NOTE:
-x264 three pass support being quite recent in MEncoder, we welcome any
-feedback you could give us on good combinations of x264 options that are
-both fast and provide good quality.
-.REss
-.
-.TP
-.B qcomp=<0\-1>
+.B qcomp=<0\-1> (2 pass only)
 quantizer compression (default: 0.6).
-This affects the ratecontrol: a lower value makes the
-bitrate more constant, while a higher value makes the quantization parameter
-more constant.
+A lower value makes the bitrate more constant,
+while a higher value makes the quantization parameter more constant.
 .
 .TP
-.B cplx_blur=<0\-999>
+.B cplx_blur=<0\-999> (2 pass only)
 Temporal blur of the estimated frame complexity, before curve compression
 (default: 20).
 Lower values allow the quantizer value to jump around more,
@@ -7261,7 +7267,7 @@ P-frames, and ensures that alternating high and low complexity frames
 (e.g. low fps animation) do not waste bits on fluctuating quantizer.
 .
 .TP
-.B qblur=<0\-99>
+.B qblur=<0\-99> (2 pass only)
 Temporal blur of the quantization parameter, after curve compression
 (default: 0.5).
 Lower values allow the quantizer value to jump around more,
@@ -7277,6 +7283,7 @@ in B-frames.
 None: direct macroblocks are not used.
 .IPs 1
 Temporal: motion vectors are interpolated from the following P-frame.
+(default)
 .IPs 2
 Spatial: motion vectors are extrapolated from neighboring blocks.
 .RE