ffmpeg 中x264接口資訊
ffmpeg -h encoder=libx264
➜ ffmpeg -h encoder=libx264
ffmpeg version 4.4.1 Copyright (c) 2000-2021 the FFmpeg developers
built with Apple clang version 13.0.0 (clang-1300.0.29.3)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.4.1_3 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-avresample --enable-videotoolbox
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
Encoder libx264 [libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10]:
General capabilities: delay threads
Threading capabilities: other
Supported pixel formats: yuv420p yuvj420p yuv422p yuvj422p yuv444p yuvj444p nv12 nv16 nv21 yuv420p10le yuv422p10le yuv444p10le nv20le gray gray10le
libx264 AVOptions:
-preset <string> E..V....... Set the encoding preset (cf. x264 --fullhelp) (default "medium")
-tune <string> E..V....... Tune the encoding params (cf. x264 --fullhelp)
-profile <string> E..V....... Set profile restrictions (cf. x264 --fullhelp)
-fastfirstpass <boolean> E..V....... Use fast settings when encoding first pass (default true)
-level <string> E..V....... Specify level (as defined by Annex A)
-passlogfile <string> E..V....... Filename for 2 pass stats
-wpredp <string> E..V....... Weighted prediction for P-frames
-a53cc <boolean> E..V....... Use A53 Closed Captions (if available) (default true)
-x264opts <string> E..V....... x264 options
-crf <float> E..V....... Select the quality for constant quality mode (from -1 to FLT_MAX) (default -1)
-crf_max <float> E..V....... In CRF mode, prevents VBV from lowering quality beyond this point. (from -1 to FLT_MAX) (default -1)
-qp <int> E..V....... Constant quantization parameter rate control method (from -1 to INT_MAX) (default -1)
-aq-mode <int> E..V....... AQ method (from -1 to INT_MAX) (default -1)
none 0 E..V.......
variance 1 E..V....... Variance AQ (complexity mask)
autovariance 2 E..V....... Auto-variance AQ
autovariance-biased 3 E..V....... Auto-variance AQ with bias to dark scenes
-aq-strength <float> E..V....... AQ strength. Reduces blocking and blurring in flat and textured areas. (from -1 to FLT_MAX) (default -1)
-psy <boolean> E..V....... Use psychovisual optimizations. (default auto)
-psy-rd <string> E..V....... Strength of psychovisual optimization, in <psy-rd>:<psy-trellis> format.
-rc-lookahead <int> E..V....... Number of frames to look ahead for frametype and ratecontrol (from -1 to INT_MAX) (default -1)
-weightb <boolean> E..V....... Weighted prediction for B-frames. (default auto)
-weightp <int> E..V....... Weighted prediction analysis method. (from -1 to INT_MAX) (default -1)
none 0 E..V.......
simple 1 E..V.......
smart 2 E..V.......
-ssim <boolean> E..V....... Calculate and print SSIM stats. (default auto)
-intra-refresh <boolean> E..V....... Use Periodic Intra Refresh instead of IDR frames. (default auto)
-bluray-compat <boolean> E..V....... Bluray compatibility workarounds. (default auto)
-b-bias <int> E..V....... Influences how often B-frames are used (from INT_MIN to INT_MAX) (default INT_MIN)
-b-pyramid <int> E..V....... Keep some B-frames as references. (from -1 to INT_MAX) (default -1)
none 0 E..V.......
strict 1 E..V....... Strictly hierarchical pyramid
normal 2 E..V....... Non-strict (not Blu-ray compatible)
-mixed-refs <boolean> E..V....... One reference per partition, as opposed to one reference per macroblock (default auto)
-8x8dct <boolean> E..V....... High profile 8x8 transform. (default auto)
-fast-pskip <boolean> E..V....... (default auto)
-aud <boolean> E..V....... Use access unit delimiters. (default auto)
-mbtree <boolean> E..V....... Use macroblock tree ratecontrol. (default auto)
-deblock <string> E..V....... Loop filter parameters, in <alpha:beta> form.
-cplxblur <float> E..V....... Reduce fluctuations in QP (before curve compression) (from -1 to FLT_MAX) (default -1)
-partitions <string> E..V....... A comma-separated list of partitions to consider. Possible values: p8x8, p4x4, b8x8, i8x8, i4x4, none, all
-direct-pred <int> E..V....... Direct MV prediction mode (from -1 to INT_MAX) (default -1)
none 0 E..V.......
spatial 1 E..V.......
temporal 2 E..V.......
auto 3 E..V.......
-slice-max-size <int> E..V....... Limit the size of each slice in bytes (from -1 to INT_MAX) (default -1)
-stats <string> E..V....... Filename for 2 pass stats
-nal-hrd <int> E..V....... Signal HRD information (requires vbv-bufsize; cbr not allowed in .mp4) (from -1 to INT_MAX) (default -1)
none 0 E..V.......
vbr 1 E..V.......
cbr 2 E..V.......
-avcintra-class <int> E..V....... AVC-Intra class 50/100/200 (from -1 to 200) (default -1)
-me_method <int> E..V....... Set motion estimation method (from -1 to 4) (default -1)
dia 0 E..V.......
hex 1 E..V.......
umh 2 E..V.......
esa 3 E..V.......
tesa 4 E..V.......
-motion-est <int> E..V....... Set motion estimation method (from -1 to 4) (default -1)
dia 0 E..V.......
hex 1 E..V.......
umh 2 E..V.......
esa 3 E..V.......
tesa 4 E..V.......
-forced-idr <boolean> E..V....... If forcing keyframes, force them as IDR frames. (default false)
-coder <int> E..V....... Coder type (from -1 to 1) (default default)
default -1 E..V.......
cavlc 0 E..V.......
cabac 1 E..V.......
vlc 0 E..V.......
ac 1 E..V.......
-b_strategy <int> E..V....... Strategy to choose between I/P/B-frames (from -1 to 2) (default -1)
-chromaoffset <int> E..V....... QP difference between chroma and luma (from INT_MIN to INT_MAX) (default 0)
-sc_threshold <int> E..V....... Scene change threshold (from INT_MIN to INT_MAX) (default -1)
-noise_reduction <int> E..V....... Noise reduction (from INT_MIN to INT_MAX) (default -1)
-x264-params <dictionary> E..V....... Override the x264 configuration using a :-separated list of key=value parameters
x264 help資訊:
➜ x264 --fullhelp
x264 core:163 r3060 5db6aa6
Syntax: x264 [options] -o outfile infile
Infile can be raw (in which case resolution is required),
or YUV4MPEG (*.y4m),
or Avisynth if compiled with support (yes).
or libav* formats if compiled with lavf support (no) or ffms support (no).
Outfile type is selected by filename:
.264 -> Raw bytestream
.mkv -> Matroska
.flv -> Flash Video
.mp4 -> MP4 if compiled with GPAC or L-SMASH support (no)
Output bit depth: 8/10
.
Options:
-h, --help List basic options
--longhelp List more options
--fullhelp List all options
Example usage:
Constant quality mode:
x264 --crf 24 -o <output> <input>
Two-pass with a bitrate of 1000kbps:
x264 --pass 1 --bitrate 1000 -o <output> <input>
x264 --pass 2 --bitrate 1000 -o <output> <input>
Lossless:
x264 --qp 0 -o <output> <input>
Maximum PSNR at the cost of speed and visual quality:
x264 --preset placebo --tune psnr -o <output> <input>
Constant bitrate at 1000kbps with a 2 second-buffer:
x264 --vbv-bufsize 2000 --bitrate 1000 -o <output> <input>
Presets:
--profile <string> Force the limits of an H.264 profile
Overrides all settings.
- baseline:
--no-8x8dct --bframes 0 --no-cabac
--cqm flat --weightp 0
No interlaced.
No lossless.
- main:
--no-8x8dct --cqm flat
No lossless.
- high:
No lossless.
- high10:
No lossless.
Support for bit depth 8-10.
- high422:
No lossless.
Support for bit depth 8-10.
Support for 4:2:0/4:2:2 chroma subsampling.
- high444:
Support for bit depth 8-10.
Support for 4:2:0/4:2:2/4:4:4 chroma subsampling.
--preset <string> Use a preset to select encoding settings [medium]
Overridden by user settings.
- ultrafast:
--no-8x8dct --aq-mode 0 --b-adapt 0
--bframes 0 --no-cabac --no-deblock
--no-mbtree --me dia --no-mixed-refs
--partitions none --rc-lookahead 0 --ref 1
--scenecut 0 --subme 0 --trellis 0
--no-weightb --weightp 0
- superfast:
--no-mbtree --me dia --no-mixed-refs
--partitions i8x8,i4x4 --rc-lookahead 0
--ref 1 --subme 1 --trellis 0 --weightp 1
- veryfast:
--no-mixed-refs --rc-lookahead 10
--ref 1 --subme 2 --trellis 0 --weightp 1
- faster:
--no-mixed-refs --rc-lookahead 20
--ref 2 --subme 4 --weightp 1
- fast:
--rc-lookahead 30 --ref 2 --subme 6
--weightp 1
- medium:
Default settings apply.
- slow:
--direct auto --rc-lookahead 50 --ref 5
--subme 8 --trellis 2
- slower:
--b-adapt 2 --direct auto --me umh
--partitions all --rc-lookahead 60
--ref 8 --subme 9 --trellis 2
- veryslow:
--b-adapt 2 --bframes 8 --direct auto
--me umh --merange 24 --partitions all
--ref 16 --subme 10 --trellis 2
--rc-lookahead 60
- placebo:
--bframes 16 --b-adapt 2 --direct auto
--slow-firstpass --no-fast-pskip
--me tesa --merange 24 --partitions all
--rc-lookahead 60 --ref 16 --subme 11
--trellis 2
--tune <string> Tune the settings for a particular type of source
or situation
Overridden by user settings.
Multiple tunings are separated by commas.
Only one psy tuning can be used at a time.
- film (psy tuning):
--deblock -1:-1 --psy-rd <unset>:0.15
- animation (psy tuning):
--bframes {+2} --deblock 1:1
--psy-rd 0.4:<unset> --aq-strength 0.6
--ref {Double if >1 else 1}
- grain (psy tuning):
--aq-strength 0.5 --no-dct-decimate
--deadzone-inter 6 --deadzone-intra 6
--deblock -2:-2 --ipratio 1.1
--pbratio 1.1 --psy-rd <unset>:0.25
--qcomp 0.8
- stillimage (psy tuning):
--aq-strength 1.2 --deblock -3:-3
--psy-rd 2.0:0.7
- psnr (psy tuning):
--aq-mode 0 --no-psy
- ssim (psy tuning):
--aq-mode 2 --no-psy
- fastdecode:
--no-cabac --no-deblock --no-weightb
--weightp 0
- zerolatency:
--bframes 0 --force-cfr --no-mbtree
--sync-lookahead 0 --sliced-threads
--rc-lookahead 0
--slow-firstpass Don't force these faster settings with --pass 1:
--no-8x8dct --me dia --partitions none
--ref 1 --subme {2 if >2 else unchanged}
--trellis 0 --fast-pskip
Frame-type options:
-I, --keyint <integer or "infinite"> Maximum GOP size [250]
-i, --min-keyint <integer> Minimum GOP size [auto]
--no-scenecut Disable adaptive I-frame decision
--scenecut <integer> How aggressively to insert extra I-frames [40]
--intra-refresh Use Periodic Intra Refresh instead of IDR frames
-b, --bframes <integer> Number of B-frames between I and P [3]
--b-adapt <integer> Adaptive B-frame decision method [1]
Higher values may lower threading efficiency.
- 0: Disabled
- 1: Fast
- 2: Optimal (slow with high --bframes)
--b-bias <integer> Influences how often B-frames are used [0]
--b-pyramid <string> Keep some B-frames as references [normal]
- none: Disabled
- strict: Strictly hierarchical pyramid
- normal: Non-strict (not Blu-ray compatible)
--open-gop Use recovery points to close GOPs
Only available with b-frames
--no-cabac Disable CABAC
-r, --ref <integer> Number of reference frames [3]
--no-deblock Disable loop filter
-f, --deblock <alpha:beta> Loop filter parameters [0:0]
--slices <integer> Number of slices per frame; forces rectangular
slices and is overridden by other slicing options
--slices-max <integer> Absolute maximum slices per frame; overrides
slice-max-size/slice-max-mbs when necessary
--slice-max-size <integer> Limit the size of each slice in bytes
--slice-max-mbs <integer> Limit the size of each slice in macroblocks (max)
--slice-min-mbs <integer> Limit the size of each slice in macroblocks (min)
--tff Enable interlaced mode (top field first)
--bff Enable interlaced mode (bottom field first)
--constrained-intra Enable constrained intra prediction.
--pulldown <string> Use soft pulldown to change frame rate
- none, 22, 32, 64, double, triple, euro (requires cfr input)
--fake-interlaced Flag stream as interlaced but encode progressive.
Makes it possible to encode 25p and 30p Blu-Ray
streams. Ignored in interlaced mode.
--frame-packing <integer> For stereoscopic videos define frame arrangement
- 0: checkerboard - pixels are alternatively from L and R
- 1: column alternation - L and R are interlaced by column
- 2: row alternation - L and R are interlaced by row
- 3: side by side - L is on the left, R on the right
- 4: top bottom - L is on top, R on bottom
- 5: frame alternation - one view per frame
- 6: mono - 2D frame without any frame packing
- 7: tile format - L is on top-left, R split across
Ratecontrol:
-q, --qp <integer> Force constant QP (0-81, 0=lossless)
-B, --bitrate <integer> Set bitrate (kbit/s)
--crf <float> Quality-based VBR (-12-51) [23.0]
--rc-lookahead <integer> Number of frames for frametype lookahead [40]
--vbv-maxrate <integer> Max local bitrate (kbit/s) [0]
--vbv-bufsize <integer> Set size of the VBV buffer (kbit) [0]
--vbv-init <float> Initial VBV buffer occupancy [0.9]
--crf-max <float> With CRF+VBV, limit RF to this value
May cause VBV underflows!
--qpmin <integer> Set min QP [0]
--qpmax <integer> Set max QP [81]
--qpstep <integer> Set max QP step [4]
--ratetol <float> Tolerance of ABR ratecontrol and VBV [1.0]
--ipratio <float> QP factor between I and P [1.40]
--pbratio <float> QP factor between P and B [1.30]
--chroma-qp-offset <integer> QP difference between chroma and luma [0]
--aq-mode <integer> AQ method [1]
- 0: Disabled
- 1: Variance AQ (complexity mask)
- 2: Auto-variance AQ
- 3: Auto-variance AQ with bias to dark scenes
--aq-strength <float> Reduces blocking and blurring in flat and
textured areas. [1.0]
-p, --pass <integer> Enable multipass ratecontrol
- 1: First pass, creates stats file
- 2: Last pass, does not overwrite stats file
- 3: Nth pass, overwrites stats file
--stats <string> Filename for 2 pass stats ["x264_2pass.log"]
--no-mbtree Disable mb-tree ratecontrol.
--qcomp <float> QP curve compression [0.60]
--cplxblur <float> Reduce fluctuations in QP (before curve compression) [20.0]
--qblur <float> Reduce fluctuations in QP (after curve compression) [0.5]
--zones <zone0>/<zone1>/... Tweak the bitrate of regions of the video
Each zone is of the form
<start frame>,<end frame>,<option>
where <option> is either
q=<integer> (force QP)
or b=<float> (bitrate multiplier)
--qpfile <string> Force frametypes and QPs for some or all frames
Format of each line: framenumber frametype QP
QP is optional (none lets x264 choose). Frametypes: I,i,K,P,B,b.
K=<I or i> depending on open-gop setting
QPs are restricted by qpmin/qpmax.
Analysis:
-A, --partitions <string> Partitions to consider ["p8x8,b8x8,i8x8,i4x4"]
- p8x8, p4x4, b8x8, i8x8, i4x4, none, all
(p4x4 requires p8x8. i8x8 requires --8x8dct.)
--direct <string> Direct MV prediction mode ["spatial"]
- none, spatial, temporal, auto
--no-weightb Disable weighted prediction for B-frames
--weightp <integer> Weighted prediction for P-frames [2]
- 0: Disabled
- 1: Weighted refs
- 2: Weighted refs + Duplicates
--me <string> Integer pixel motion estimation method ["hex"]
- dia: diamond search, radius 1 (fast)
- hex: hexagonal search, radius 2
- umh: uneven multi-hexagon search
- esa: exhaustive search
- tesa: hadamard exhaustive search (slow)
--merange <integer> Maximum motion vector search range [16]
--mvrange <integer> Maximum motion vector length [-1 (auto)]
--mvrange-thread <int> Minimum buffer between threads [-1 (auto)]
-m, --subme <integer> Subpixel motion estimation and mode decision [7]
- 0: fullpel only (not recommended)
- 1: SAD mode decision, one qpel iteration
- 2: SATD mode decision
- 3-5: Progressively more qpel
- 6: RD mode decision for I/P-frames
- 7: RD mode decision for all frames
- 8: RD refinement for I/P-frames
- 9: RD refinement for all frames
- 10: QP-RD - requires trellis=2, aq-mode>0
- 11: Full RD: disable all early terminations
--psy-rd <float:float> Strength of psychovisual optimization ["1.0:0.0"]
#1: RD (requires subme>=6)
#2: Trellis (requires trellis, experimental)
--no-psy Disable all visual optimizations that worsen
both PSNR and SSIM.
--no-mixed-refs Don't decide references on a per partition basis
--no-chroma-me Ignore chroma in motion estimation
--no-8x8dct Disable adaptive spatial transform size
-t, --trellis <integer> Trellis RD quantization. [1]
- 0: disabled
- 1: enabled only on the final encode of a MB
- 2: enabled on all mode decisions
--no-fast-pskip Disables early SKIP detection on P-frames
--no-dct-decimate Disables coefficient thresholding on P-frames
--nr <integer> Noise reduction [0]
--deadzone-inter <int> Set the size of the inter luma quantization deadzone [21]
--deadzone-intra <int> Set the size of the intra luma quantization deadzone [11]
Deadzones should be in the range 0 - 32.
--cqm <string> Preset quant matrices ["flat"]
- flat, jvt
--cqmfile <string> Read custom quant matrices from a JM-compatible file
Overrides any other --cqm* options.
--cqm4 <list> Set all 4x4 quant matrices
Takes a comma-separated list of 16 integers.
--cqm8 <list> Set all 8x8 quant matrices
Takes a comma-separated list of 64 integers.
--cqm4i, --cqm4p, --cqm8i, --cqm8p <list>
Set both luma and chroma quant matrices
--cqm4iy, --cqm4ic, --cqm4py, --cqm4pc <list>
Set individual quant matrices
Video Usability Info (Annex E):
The VUI settings are not used by the encoder but are merely suggestions to
the playback equipment. See doc/vui.txt for details. Use at your own risk.
--overscan <string> Specify crop overscan setting ["undef"]
- undef, show, crop
--videoformat <string> Specify video format ["undef"]
- component, pal, ntsc, secam, mac, undef
--range <string> Specify color range ["auto"]
- auto, tv, pc
--colorprim <string> Specify color primaries ["undef"]
- undef, bt709, bt470m, bt470bg, smpte170m,
smpte240m, film, bt2020, smpte428,
smpte431, smpte432
--transfer <string> Specify transfer characteristics ["undef"]
- undef, bt709, bt470m, bt470bg, smpte170m,
smpte240m, linear, log100, log316,
iec61966-2-4, bt1361e, iec61966-2-1,
bt2020-10, bt2020-12, smpte2084, smpte428,
arib-std-b67
--colormatrix <string> Specify color matrix setting ["???"]
- undef, bt709, fcc, bt470bg, smpte170m,
smpte240m, GBR, YCgCo, bt2020nc, bt2020c,
smpte2085, chroma-derived-nc,
chroma-derived-c, ICtCp
--chromaloc <integer> Specify chroma sample location (0 to 5) [0]
--mastering-display <string> Specify 'G(x,y)B(x,y)R(x,y)WP(x,y)L(max,min)'
for primaries, white point, and display brightness
--cll <string> Specify 'max_content,max_frame_average' content
light levels
--alternative-transfer <string> Specify an alternative transfer
characteristics ["undef"]
- same values as --transfer
--nal-hrd <string> Signal HRD information (requires vbv-bufsize)
- none, vbr, cbr (cbr not allowed in .mp4)
--filler Force hard-CBR and generate filler (implied by
--nal-hrd cbr)
--pic-struct Force pic_struct in Picture Timing SEI
--crop-rect <string> Add 'left,top,right,bottom' to the bitstream-level
cropping rectangle
Input/Output:
-o, --output <string> Specify output file
--muxer <string> Specify output container format ["auto"]
- auto, raw, mkv, flv
--demuxer <string> Specify input container format ["auto"]
- auto, raw, y4m, avs
--input-fmt <string> Specify input file format (requires lavf support)
--input-csp <string> Specify input colorspace format for raw input
- valid csps for `raw' demuxer:
i400, i420, yv12, nv12, nv21, i422, yv16, nv16,
yuyv, uyvy, i444, yv24, bgr, bgra, rgb
--output-csp <string> Specify output colorspace ["i420"]
- i400, i420, i422, i444, rgb
--input-depth <integer> Specify input bit depth for raw input
--output-depth <integer> Specify output bit depth
--input-range <string> Specify input color range ["auto"]
- auto, tv, pc
--input-res <intxint> Specify input resolution (width x height)
--index <string> Filename for input index file
--sar width:height Specify Sample Aspect Ratio
--fps <float|rational> Specify framerate
--seek <integer> First frame to encode
--frames <integer> Maximum number of frames to encode
--level <string> Specify level (as defined by Annex A)
--bluray-compat Enable compatibility hacks for Blu-ray support
--avcintra-class <integer> Use compatibility hacks for AVC-Intra class
- 50, 100, 200
--avcintra-flavor <string> AVC-Intra flavor ["panasonic"]
- panasonic, sony
--stitchable Don't optimize headers based on video content
Ensures ability to recombine a segmented encode
-v, --verbose Print stats for each frame
--no-progress Don't show the progress indicator while encoding
--quiet Quiet Mode
--log-level <string> Specify the maximum level of logging ["info"]
- none, error, warning, info, debug
--psnr Enable PSNR computation
--ssim Enable SSIM computation
--threads <integer> Force a specific number of threads
--lookahead-threads <integer> Force a specific number of lookahead threads
--sliced-threads Low-latency but lower-efficiency threading
--thread-input Run Avisynth in its own thread
--sync-lookahead <integer> Number of buffer frames for threaded lookahead
--non-deterministic Slightly improve quality of SMP, at the cost of repeatability
--cpu-independent Ensure exact reproducibility across different cpus,
as opposed to letting them select different algorithms
--asm <integer> Override CPU detection
--no-asm Disable all CPU optimizations
--opencl Enable use of OpenCL
--opencl-clbin <string> Specify path of compiled OpenCL kernel cache
--opencl-device <integer> Specify OpenCL device ordinal
--dump-yuv <string> Save reconstructed frames
--sps-id <integer> Set SPS and PPS id numbers [0]
--aud Use access unit delimiters
--force-cfr Force constant framerate timestamp generation
--tcfile-in <string> Force timestamp generation with timecode file
--tcfile-out <string> Output timecode v2 file from input timestamps
--timebase <int/int> Specify timebase numerator and denominator
<integer> Specify timebase numerator for input timecode file
or specify timebase denominator for other input
--dts-compress Eliminate initial delay with container DTS hack
Filtering:
--vf, --video-filter <filter0>/<filter1>/... Apply video filtering to the input file
Filter options may be specified in <filter>:<option>=<value> format.
Available filters:
crop:left,top,right,bottom
removes pixels from the edges of the frame
select_every:step,offset1[,...]
apply a selection pattern to input frames
step: the number of frames in the pattern
offsets: the offset into the step to select a frame
see: http://avisynth.nl/index.php/Select#SelectEvery
Reference Frame:
即ref,意義是該P幀能參考在它之前的最多視訊幀數量。ref越大,壓縮比就越高,解碼的硬體要求也會更高,編碼效率也會更長,同時ref決定了level值。一般來說動漫編碼的ref超過6基本對壓縮率的貢獻不超過1%。如果要在移動裝置上觀看(一般來說硬解需要level<=4.1,軟解允許level>4.1),在level4.1下,720P不能超過9,1080P不能超過4。如果在電腦上觀看,建議動漫ref=5~6,電影ref=3~4。如果1080P的 ref>4,設定level值;
Maximum B-Frame:
即bframe,意義是最大允許連續的B幀數量,在預設下,B幀的平均量化值是最高的,并且壓縮率也是最高的,越大的B幀能改善壓縮比,但是Adaptive B-Frame=optimal下,越大的B幀意味着越慢的編碼速度,但是在高速變化的場景中,bframe>=4對壓縮比的改善很小,在靜止或緩慢變化的的場景,bframe>7對壓縮比的改善很小。建議動漫根據情況bframe=5~7,電影bframe=3~5;
CABAC Entropy Coding:
使能,相比CAVLC算法改善20%的壓縮比,對編碼效率影響不大;
8×8 Transform:
使能,成本效益很高,能改善5%以上的壓縮比,對編碼效率的影響不大;
Pyramidal B-Frame:
是否允許B幀作為參考幀,選擇normal改善壓縮比,對編碼效率影響不大;
NO DCT Decimation:
使能,可以改善壓縮比;
Adaptive B-Frame:
PB幀決策算法,建議Optimal,相比Fast和Off能有更高的品質;
Adaptive Direct Mode:
建議Automatic;
Motion Estimation Method:
運動預測算法。對編碼效率影響較大,時間允許的話建議uneven Multi-Hexagon,否則可以選擇Hexagon。Transformed Exhaustives雖然最好,但是成本效益低,多花30%以上的時間對壓縮率的改善不及3%;
Subpixel ME & Mode Decision:
值越大越好,對編碼效率影響較大,建議時間允許的話選擇9~10,最好在7以上;
Motion Estimation Range:
運動偵查半徑,但是對編碼效率影響很大。動作片能适當加大,變化平緩的片源保持16預設,建議值16~32;
Partition Types:
設定允許的宏塊。時間允許建議All,否則Most;
Trellis:
若想保留高品質、讓畫面更銳利、品質更好,并改善壓縮比建議Always;對編碼速度有一定的影響;
Adaptive Quantization:
即aq,自适應量化。提高aq值能改善背景的品質,防止x264碼率配置設定不合理造成背景品質下降(尤其是平滑低細節的暗場區域),建議幹淨的畫面保持1。若片源有較多噪點,則應該适當降低aq值,防止浪費碼率,噪點較多的片源則使用0.6~0.8;
Psychovisual Rate Distortion:
即psy-rd,有保留細節,防止banding和ringing,不容易讓畫面模糊的作用,建議在高細節的片源使用較高的psy-rd(1),多噪點的片源使用較低的psy-rd(0.5);
Psychovisual Trellis:
實驗性的,不建議使用,保持0;
Deblock:
簡單說正值去方塊,負值銳化;壓制高品質的視訊建議取-2,-2,在BitRate壓制模式下,建議-1~0,-1~0;如果噪點較多,建議2,2;