From 57017402ede8d7f6c53bc33bff71b2edba9ab1de Mon Sep 17 00:00:00 2001 From: diego Date: Mon, 9 Aug 2004 11:12:52 +0000 Subject: XviD option descriptions, patch by Guillaume POIRIER git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@12979 b3059339-0415-0410-9bf9-f77b7e298cf2 --- DOCS/man/en/mplayer.1 | 149 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 112 insertions(+), 37 deletions(-) diff --git a/DOCS/man/en/mplayer.1 b/DOCS/man/en/mplayer.1 index f4945999da..c4acf4dab6 100644 --- a/DOCS/man/en/mplayer.1 +++ b/DOCS/man/en/mplayer.1 @@ -5440,76 +5440,106 @@ specify the pass in 2pass mode .B bitrate= sets the bitrate to be used in kbits/\:second if <16000 or in bits/\:second if >16000 -(CBR or 2pass mode, default=687 kbits/s) +(CBR or 2pass mode, default: 687 kbits/s) .TP .B fixed_quant=<1\-31> switch to fixed quantizer mode and specify the quantizer to be used .TP .B me_quality=<0\-6> -specify the motion detection quality (default=6) +This option controls the motion estimation subsystem. +The higher the value, the more precise the estimation should be. +The more precise the motion estimation is, the more bits can be saved. +Precision is gained at the expense of CPU time so decrease this setting if +you need realtime encoding. +(default: 6) .TP .B interlacing -enable support for interlaced content (default=off) +For interlaced video material, turn this option on. +.I Note: +This option does not deinterlace video, it encodes it field-based +(default: off). .TP .B 4mv\ \ \ \ use 4 motion vectors per macro-block, might give better compression at the -cost of a slower encoding (default=off) +cost of a slower encoding (default: off). +.br +.I WARNING: +This option doesn't exist in XviD-1.0.x. .TP .B rc_reaction_delay_factor= -specify how fast the rate control reacts, lower values are faster +This parameter controls the delay in frames before the CBR rate controller +will react to bitrate changes and will try to compensate the change to obtain +a constant bitrate over an averaging range of frames. .TP .B rc_averaging_period= -period to reach the required average +Real CBR is hard to achieve. +Depending on the video material, bitrate can be variable, and hard to predict. +That's why XviD uses an averaging period for which it guarantees a given +amount of bits (minus a small variation). +This settings expresses the "number of frames" for which XviD averages +bitrate and tries to achieve CBR. .TP .B rc_buffer= size of the rate control buffer .TP .B quant_range=<1\-31>\-<1\-31>[/<1\-31>\-<1\-31>] -min & max quantizer for all frames (default=2\-31, CBR mode) +min & max quantizer for all frames (default: 2\-31, CBR mode) .br -min & max quantizer for I/P frames (default=2\-31/2\-31, 2pass mode) +min & max quantizer for I/P frames (default: 2\-31/2\-31, 2pass mode) .TP .B min_key_interval= -minimum interval between key frames (default=0, 2pass only) +minimum interval between key frames (default: 0, 2pass only) .TP .B max_key_interval= -maximum interval between key frames (default=10*fps) +maximum interval between key frames (default: 10*fps) .TP .B mpeg_quant -use MPEG quantizers instead of H.263 (default=off) +use MPEG quantizers instead of H.263. +For high bitrates, you will find that MPEG quantization preserves more detail. +For low bitrates, the smoothing of H.263 will give you less block noise. +When using custom matrices, MPEG must be used. +(default: off) .TP .B mod_quant decide whether to use MPEG or H.263 quantizers on a frame-by-frame basis. -(default=off, 2pass mode only) +(default: off, 2pass mode only) .TP .B greyscale -encode in black & white (default=off) +Make XviD discard chroma planes so the encoded video is greyscale only. +Note that this does not speed up encoding, it just prevents chroma data +from being written in the last stage of encoding. +(default: off) .TP .B debug\ \ -Save per-frame statistics in xvid.dbg (default=off). +Save per-frame statistics in ./xvid.dbg (default: off). This is NOT the 2pass control file. .TP .B keyframe_boost=<0\-1000> -(default=0, 2pass mode only) +Shift some bits from the pool for other frame types to intra frames, +thus improving keyframe quality. +(default: 0, 2pass mode only) .TP .B kfthreshold= -(default=10, 2pass mode only) +(default: 10, 2pass mode only) .TP .B kfreduction=<0\-100> -(default=30, 2pass mode only) +The above two settings can be used to adjust the size of keyframes that +you consider too close to the first (in a row). +kfthreshold sets the range in which keyframes are reduced, and +kfreduction determines the bitrate reduction they get. +The last i-frame will get treated normally. +(default: 30, 2pass mode only) .RE .PP The following options are only available with the latest stable -XviD 0.9.2 (api3) version and are marked as experimental and unstable. -The newest development version of XviD 1.0 (api4) supports -them fully. +releases of XviD 1.0.x (api4). .TP .B packed\ -create a bitstream that can be decoded delay-free (default=off) +create a bitstream that can be decoded delay-free (default: off) .br .I WARNING: -this will generate an illegal bitstream, and WILL NOT be +this will generate an illegal bitstream, and WILL NOT be decodeable by ISO-MPEG4 decoders except DivX/libavcodec/XviD .br .I WARNING: @@ -5517,40 +5547,84 @@ this will also store a fake DivX version in the file so the bug autodetection of some decoders might be confused .TP .B divx5bvop -generate DivX5 compatible B-frames (default=on) +generate DivX5 compatible B-frames (default: on) .TP .B qpel\ \ \ -enable quarter-pixel motion estimation (default=off) +MPEG4 uses a half pixel precision for its motion search by default. +The standard proposes a mode where encoders are allowed to use quarter +pixel precision. +This option usually results in a sharper image. +Unfortunately it has a great impact on bitrate and sometimes the +higher bitrate use will prevent it from giving a better image +quality at a fixed bitrate. +It's better to test with and without this option and see whether it +is worth activating. +(default: off) .TP .B gmc\ \ \ \ -enable global motion compensation, may save bits on panning scenes (default=off) +Enable Global Motion Compensation, which makes XviD generate Sprite +Frames which best describe Pan/Zoom/Rotating images. +The decision whether to activate this option or not to save bits +depends highly on the video material. +(default: off) +.TP +.B trellis +Trellis Quantization is a kind of adaptive quantization method that +saves bits by modifying quantized coefficients to make them more +compressible by the entropy encoder. +Its impact on quality is good, and if VHQ uses too much CPU for you, +this setting can be a good alternative to save a few bits (and gain +quality at fixed bitrate) at a lesser cost than with VHQ (default: off). +.TP +.B cartoon +Activate this if your encoded sequence is an anime/cartoon. +It modifies some XviD internal thresholds so XviD takes better decisions on +frame types and motion vectors for flat looking cartoons. .TP .B chroma_me -uses chroma information to estimate motion (default=off) +The usual motion estimation algorithm uses only the luminance information to +find the best motion vector. +However for some video material, using the chroma planes can help find +better vectors. +This setting toggles the use of chroma planes for motion estimation +(default: off). .TP .B chroma_opt -enable a chroma optimizer prefilter (default=off) +enable a chroma optimizer prefilter (default: off) .TP .B reduced -enable encoding reduced resolution frames (default=off) +enable encoding reduced resolution frames (default: off) .TP .B max_bframes=<0\-4> -maximum number of B frames to put between I/P frames (default=0) +maximum number of B frames to put between I/P frames (default: 0) .TP .B bquant_ratio=<0\-1000> -quantizer ratio between B and non B frames, 150=1.50 (default=150) +quantizer ratio between B and non B frames, 150=1.50 (default: 150) .TP .B bquant_offset=<-1000\-1000> -quantizer offset between B and non B frames, 100=1.00 (default=100) +quantizer offset between B and non B frames, 100=1.00 (default: 100) .TP .B bf_threshold=<-255\-255> -change the probability of a frame to be a bframe (default=0) +Sometimes B frames do not look good, and introduce artifacts when most of +the frame is static and some small zones have high motion (in a static +scene with a man talking, his mouth will probably look bad if what is +surrounding the man and his mouth is completly static). +This setting allows you to favorize or not, the use of B frames. +The higher the value, the higher the probability of B frames being used. +(default: 0) .TP .B hq_ac\ \ -enable a better prediction of AC component (default=off) +Activates High Quality AC coefficient prediction from neighbor blocks. +(default:off) .TP .B vhq=<0\-4> -enable a higher quality ME search using DCT, faster to slower: +The motion search algorithm is based on a search in the usual color domain +and tries to find a motion vector that minimizes the difference between the +reference frame and the encoded frame. +With this setting activated, XviD will also use the frequency domain (DCT) +to search for a motion vector that minimizes not only the spatial +difference but also the encoding length of the block. +Fastest to slowest: .PD 0 .RSs .IPs 0 @@ -5569,8 +5643,8 @@ wide search .B aspect= Store movie aspect internally, just like MPEG files. Much nicer solution than rescaling, because quality isn't decreased. -MPlayer and few others players will play these files correctly, others will display -them with the wrong aspect. +MPlayer and a few others players will play these files correctly, others +will display them with the wrong aspect. The aspect parameter can be given as a ratio or a floating point number. .TP .B autoaspect @@ -5580,7 +5654,8 @@ filter chain. .TP .B psnr\ \ \ Print the psnr (peak signal to noise ratio) for the whole video after encoding -and store the per frame psnr in a file with a name like 'psnr_hhmmss.log'. +and store the per frame psnr in a file with a name like 'psnr_hhmmss.log' in +the current directory. Returned values are in dB (decibel), the higher the better. . . -- cgit v1.2.3