audio codec (default: mp2)
mp2 | MPEG Layer 2 |
mp3 | MPEG Layer 3 |
ac3 | AC3 |
adpcm_ima_wav | IMA Adaptive PCM (4bits per sample, 4:1 compression) |
sonic | Experimental lossy/lossless codec |
audio bitrate in kbps (default: 224)
Use the specified Windows audio format tag (e.g. atag=0x55).
Use only bit exact algorithms (except (I)DCT). Additionally bit_exact disables several optimizations and thus should only be used for regression tests, which need binary identical files even if the encoder version changes. This also suppresses the user_data header in MPEG-4 streams. Do not use this option unless you know exactly what you are doing.
(I)DCTを除いたロスレスな変換のみを使わせます。さらにこのオプションはいくつかの最適化を無効にするため、エンコーダーのバージョンが変わったときでもバイナリとして同一なファイルを必要とする退行テストのときにのみ使用されるべきです。これはMPEG-4ストリームの中のuser_dataヘッダーも抑制します。何をするのかわからないならこのオプションは使わないでください。
Maximum number of threads to use (default: 1). May have a slight negative effect on motion estimation.
Employ the specified codec (default: mpeg4).
mjpeg | Motion JPEG |
ljpeg | Lossless JPEG |
h261 | H.261 |
h263 | H.263 |
h263p | H.263+ |
mpeg4 | MPEG-4 (DivX 4/5) |
msmpeg4 | DivX 3 |
msmpeg4v2 | MS MPEG4v2 |
wmv1 | Windows Media Video, version 1 (AKA WMV7) |
wmv2 | Windows Media Video, version 2 (AKA WMV8) |
rv10 | an old RealVideo codec |
mpeg1video | MPEG-1 video |
mpeg2video | MPEG-2 video |
huffyuv | HuffYUV |
ffvhuff | nonstandard 20% smaller HuffYUV using YV12 |
asv1 | ASUS Video v1 |
asv2 | ASUS Video v2 |
ffv1 (also see: vstrict) | FFmpeg’s lossless video codec |
flv | Sorenson H.263 used in Flash Video |
dvvideo | Sony Digital Video |
svq1 | Apple Sorenson Video 1 |
snow (also see: vstrict) | FFmpeg’s experimental wavelet-based codec |
minimum quantizer (pass 1/2)
Minimum Lagrange multiplier for ratecontrol, you probably want it to be equal to or lower than vqmin (default: 2.0).
maximum Lagrange multiplier for ratecontrol (default: 31.0)
Constant quantizer / constant quality encoding (selects fixed quantizer mode). A lower value means better quality but larger files (default: 0). In case of snow codec, value 0 means lossless encoding. Since the other codecs do not support this, vqscale=0 will be ignored and variable quantizers are used, which is the default. 1 is not recommended (see vqmin for details).
Maximum quantizer (pass 1/2), 10−31 should be a sane range (default: 31).
obsolete, use vqmin
obsolete, use vqmax
maximum quantizer difference between consecutive I- or P-frames (pass 1/2) (default: 3)
maximum number of B-frames between non-B-frames:
motion estimation method. Available methods are:
動き予測
NOTE: 0−3 currently ignores the amount of bits spent, so quality may be low.
motion estimation search range (default: 0 (unlimited))
Macroblock decision algorithm (high quality mode), encode each macro block in all modes and choose the best. This is slow but results in better quality and file size.
Same as mbd=1, kept for compatibility reasons.
Allow 4 motion vectors per macroblock (slightly better quality). Works better if used with mbd>0.
overlapped block motion compensation (H.263+)
loop filter (H.263+) note, this is broken
Does absolutely nothing at the moment.
maximum interval between keyframes in frames (default: 250 or one keyframe every ten seconds in a 25fps movie. This is the recommended default for MPEG-4). Most codecs require regular keyframes in order to limit the accumulation of mismatch error. Keyframes are also needed for seeking, as seeking is only possible to a keyframe - but keyframes need more space than other frames, so larger numbers here mean slightly smaller files but less precise seeking. 0 is equivalent to 1, which makes every frame a keyframe. Values >300 are not recommended as the quality might be bad depending upon decoder, encoder and luck. It is a common for MPEG-1/2 to use values <=30.
Threshold for scene change detection. A keyframe is inserted by libavcodec when it detects a scene change. You can specify the sensitivity of the detection with this option. -1000000000 means there is a scene change detected at every frame, 1000000000 means no scene changes are detected (default: 0).
Causes frames with higher quantizers to be more likely to trigger a scene change detection and make libavcodec use an I-frame (default: 1). 1−16 is a sane range. Values between 2 and 6 may yield increasing PSNR (up to approximately 0.04 dB) and better placement of I-frames in high-motion scenes. Higher values than 6 may give very slightly better PSNR (approximately 0.01 dB more than sc_factor=6), but noticably worse visual quality.
strategy to choose between I/P/B-frames:
Adjusts how sensitively vb_strategy=1 detects motion and avoids using B-frames (default: 40). Lower sensitivities will result in more B-frames. Using more B-frames usually improves PSNR, but too many B-frames can hurt quality in high-motion scenes. Unless there is an extremely high amount of motion, b_sensitivity can safely be lowered below the default; 10 is a reasonable value in most cases.
Downscales frames for dynamic B-frame decision (default: 0). Each time brd_scale is increased by one, the frame dimensions are divided by two, which improves speed by a factor of four. Both dimensions of the fully downscaled frame must be even numbers, so brd_scale=1 requires the original dimensions to be multiples of four, brd_scale=2 requires multiples of eight, etc. In other words, the dimensions of the original frame must both be divisible by 2^(brd_scale+1) with no remainder.
Refine the two motion vectors used in bidirectional macroblocks, rather than re-using vectors from the forward and backward searches. This option has no effect without B-frames.
Activates internal two (or more) pass mode, only specify if you wish to use two (or more) pass encoding.
Here is how it works, and how to use it: The first pass (vpass=1) writes the statistics file. You might want to deactivate some CPU-hungry options, like "turbo" mode does. In two pass mode, the second pass (vpass=2) reads the statistics file and bases ratecontrol decisions on it. In N-pass mode, the second pass (vpass=3, that is not a typo) does both: It first reads the statistics, 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 like "qns". You can run this same pass over and over to refine the encode. Each subsequent pass will use the statistics from the previous pass to improve. The final pass can include any CPU-hungry encoding options. If you want a 2 pass encode, use first vpass=1, and then vpass=2. If you want a 3 or more pass encode, use vpass=1 for the first pass and then vpass=3 and then vpass=3 again and again until you are satisfied with the encode.
huffyuv:
Dramatically speeds up pass one using faster algorithms and disabling CPU-intensive options. This will probably reduce global PSNR a little bit (around 0.01dB) and change individual frame type and PSNR a little bit more (up to 0.03dB).
Store movie aspect internally, just like with MPEG files. Much nicer than rescaling, because quality is not decreased. Only MPlayer will play these files correctly, other players will display them with wrong aspect. The aspect parameter can be given as a ratio or a floating point number.
EXAMPLE:
aspect=16/9 or aspect=1.78
Same as the aspect option, but automatically computes aspect, taking into account all the adjustments (crop/expand/scale/ etc.) made in the filter chain. Does not incur a performance penalty, so you can safely leave it always on.
Specify bitrate (pass 1/2) (default: 800). WARNING: 1kbit = 1000 bits
4−16000 | (in kbit) |
16001−24000000 | (in bit) |
approximated file size tolerance in kbit. 1000−100000 is a sane range. (warning: 1kbit = 1000 bits) (default: 8000) NOTE: vratetol should not be too large during the second pass or there might be problems if vrc_(min|max)rate is used.
maximum bitrate in kbit/sec (pass 1/2) (default: 0, unlimited)
minimum bitrate in kbit/sec (pass 1/2) (default: 0, unlimited)
buffer size in kbit (pass 1/2). For MPEG-1/2 this also sets the vbv buffer size, use 327 for VCD, 917 for SVCD and 1835 for DVD.
currently useless
Ratecontrol method. Note that some of the ratecontrol-affecting options will have no effect if vrc_strategy is not set to 0.
quantizer factor between B- and non-B-frames (pass 1/2) (default: 1.25)
quantizer factor between I- and non-I-frames (pass 1/2) (default: 0.8)
quantizer offset between B- and non-B-frames (pass 1/2) (default: 1.25)
(pass 1/2) (default: 0.0) if v{b|i}_qfactor > 0 I/B-frame quantizer = P-frame quantizer * v{b|i}_qfactor + v{b|i}_qoffset else do normal ratecontrol (do not lock to next P-frame quantizer) and set q= -q * v{b|i}_qfactor + v{b|i}_qoffset HINT: To do constant quantizer encoding with different quantizers for I/P- and B-frames you can use: lmin= <ip_quant>:lmax= <ip_quant>:vb_qfactor= <b_quant/ip_quant>.
Quantizer blur (default: 0.5), larger values will average the quantizer more over time (slower change).
Quantizer gaussian blur (default: 0.5), larger values will average the quantizer more over time (slower change).
Quantizer compression, vrc_eq depends upon this (pass 1/2) (default: 0.5). For instance, assuming the default rate control equation is used, if vqcomp=1.0, the ratecontrol allocates to each frame the number of bits needed to encode them all at the same QP. If vqcomp=0.0, the ratecontrol allocates the same number of bits to each frame, i.e. strict CBR. NOTE: Those are extreme settings and should never be used. Perceptual quality will be optimal somewhere in between these two extremes.
main ratecontrol equation (pass 1/2)
infix operators:
+,-,*,/,^
variables:
functions:
User specified quality for specific parts (ending, credits, ...) (pass 1/2). The options are <start-frame>, <end-frame>, <quality>[/<start-frame>, <end-frame>, <quality>[/...]]:
initial complexity (pass 1)
initial buffer occupancy, as a fraction of vrc_buf_size (default: 0.9)
Specify how to keep the quantizer between qmin and qmax (pass 1/2).
Sets single coefficient elimination threshold for luminance. Negative values will also consider the DC coefficient (should be at least -4 or lower for encoding at quant=1):
Sets single coefficient elimination threshold for chrominance. Negative values will also consider the DC coefficient (should be at least -4 or lower for encoding at quant=1):
strict standard compliance
Data partitioning. Adds 2 Bytes per video packet, improves error-resistance when transferring over unreliable channels (e.g. streaming over the internet). Each video packet will be encoded in 3 separate partitions:
MV & DC are most important, loosing them looks far worse than loosing the AC and the 1. & 2. partition. (MV & DC) are far smaller than the 3. partition (AC) meaning that errors will hit the AC partition much more often than the MV & DC partitions. Thus, the picture will look better with partitioning than without, as without partitioning an error will trash AC/DC/MV equally.
Video packet size, improves error-resistance.
slice structured mode for H.263+
grayscale only encoding (faster)
DCT algorithm
IDCT algorithm NOTE: To the best of our knowledge all these IDCTs do pass the IEEE1180 tests.
Luminance masking is a ’psychosensory’ setting that is supposed to make use of the fact that the human eye tends to notice fewer details in very bright parts of the picture. Luminance masking compresses bright areas stronger than medium ones, so it will save bits that can be spent again on other frames, raising overall subjective quality, while possibly reducing PSNR. WARNING: Be careful, overly large values can cause disastrous things. WARNING: Large values might look good on some monitors but may look horrible on other monitors.
Darkness masking is a ’psychosensory’ setting that is supposed to make use of the fact that the human eye tends to notice fewer details in very dark parts of the picture. Darkness masking compresses dark areas stronger than medium ones, so it will save bits that can be spent again on other frames, raising overall subjective quality, while possibly reducing PSNR. WARNING: Be careful, overly large values can cause disastrous things. WARNING: Large values might look good on some monitors but may look horrible on other monitors / TV / TFT.
Temporal complexity masking (default: 0.0 (disabled)). Imagine a scene with a bird flying across the whole scene; tcplx_mask will raise the quantizers of the bird’s macroblocks (thus decreasing their quality), as the human eye usually does not have time to see all the bird’s details. Be warned that if the masked object stops (e.g. the bird lands) it is likely to look horrible for a short period of time, until the encoder figures out that the object is not moving and needs refined blocks. The saved bits will be spent on other parts of the video, which may increase subjective quality, provided that tcplx_mask is carefully chosen.
Spatial complexity masking. Larger values help against blockiness, if no deblocking filter is used for decoding, which is maybe not a good idea. Imagine a scene with grass (which usually has great spatial complexity), a blue sky and a house; scplx_mask will raise the quantizers of the grass’ macroblocks, thus decreasing its quality, in order to spend more bits on the sky and the house. HINT: Crop any black borders completely as they will reduce the quality of the macroblocks (also applies without scplx_mask).
NOTE: This setting does not have the same effect as using a custom matrix that would compress high frequencies harder, as scplx_mask will reduce the quality of P blocks even if only DC is changing. The result of scplx_mask will probably not look as good.
Reduces the quality of inter blocks. This is equivalent to increasing the quality of intra blocks, because the same average bitrate will be distributed by the rate controller to the whole video sequence (default: 0.0 (disabled)). p_mask=1.0 doubles the bits allocated to each intra block.
border-processing for MPEG-style encoders. Border processing increases the quantizer for macroblocks which are less than 1/5th of the frame width/height away from the frame border, since they are often visually less important.
Normalize adaptive quantization (experimental). When using adaptive quantization (*_mask), the average per-MB quantizer may no longer match the requested frame-level quantizer. Naq will attempt to adjust the per-MB quantizers to maintain the proper average.
Use interlaced DCT.
Use interlaced motion estimation (mutually exclusive with qpel).
Use alternative scantable.
(for HuffYUV)
(for lossless JPEG)
(for ffv1)
(for ffv1)
(for ffvhuff)
:0predetermined Huffman tables (builtin or two pass)
Use quarter pel motion compensation (mutually exclusive with ilme). HINT: This seems only useful for high bitrate encodings.
Sets the comparison function for the macroblock decision, only used if mbd=0.
Sets the comparison function for interlaced DCT decision (see mbcmp for available comparison functions).
Sets the comparison function for motion estimation pre pass (see mbcmp for available comparison functions) (default: 0).
Sets the comparison function for full pel motion estimation (see mbcmp for available comparison functions) (default: 0).
Sets the comparison function for sub pel motion estimation (see mbcmp for available comparison functions) (default: 0).
This setting controls NSSE weight, where larger weights will result in more noise. 0 NSSE is identical to SSE You may find this useful if you prefer to keep some noise in your encoded video rather than filtering it away before encoding (default: 8).
diamond type and size for motion estimation pre-pass
Diamond type & size for motion estimation. Motion search is an iterative process. Using a small diamond does not limit the search to finding only small motion vectors. It is just somewhat more likely to stop before finding the very best motion vector, especially when noise is involved. Bigger diamonds allow a wider search for the best motion vector, thus are slower but result in better quality. Big normal diamonds are better quality than shape-adaptive diamonds. Shape-adaptive diamonds are a good tradeoff between speed and quality. NOTE: The sizes of the normal diamonds and shape adaptive ones do not have the same meaning.
Trellis searched quantization. This will find the optimal encoding for each 8x8 block. Trellis searched quantization is quite simply an optimal quantization in the PSNR versus bitrate sense (Assuming that there would be no rounding errors introduced by the IDCT, which is obviously not the case.). It simply finds a block for the minimum of error and lambda*bits.
Rate distorted optimal coded block pattern. Will select the coded block pattern which minimizes distortion + lambda*rate. This can only be used together with trellis quantization.
Try to encode each MB with MV=<0,0> and choose the better one. This has no effect if mbd=0.
When surrounding motion vectors are <0,0> and the motion estimation score of the current block is less than mv0_threshold, <0,0> is used for the motion vector and further motion estimation is skipped (default: 256). Lowering mv0_threshold to 0 can give a slight (0.01dB) PSNR increase and possibly make the encoded video look slightly better; raising mv0_threshold past 320 results in diminished PSNR and visual quality. Higher values speed up encoding very slightly (usually less than 1%, depending on the other options used). NOTE: This option does not require mv0 to be enabled.
rate distorted optimal quantization parameter (QP) for the given lambda of each macroblock
amount of motion predictors from the previous frame
motion estimation pre-pass
subpel refinement quality (for qpel) (default: 8 (high quality)) NOTE: This has a significant effect on speed.
number of reference frames to consider for motion compensation (Snow only) (default: 1)
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’. Returned values are in dB (decibel), the higher the better.
Use MPEG quantizers instead of H.263.
Enable AC prediction for MPEG-4 or advanced intra prediction for H.263+. This will improve quality very slightly (around 0.02 dB PSNR) and slow down encoding very slightly (about 1%). NOTE: vqmin should be 8 or larger for H.263+ AIC.
alternative inter vlc for H.263+
unlimited MVs (H.263+ only) Allows encoding of arbitrarily long MVs.
intra quantizer bias (256 equals 1.0, MPEG style quantizer default: 96, H.263 style quantizer default: 0) NOTE: The H.263 MMX quantizer cannot handle positive biases (set vfdct=1 or 2), the MPEG MMX quantizer cannot handle negative biases (set vfdct=1 or 2).
inter quantizer bias (256 equals 1.0, MPEG style quantizer default: 0, H.263 style quantizer default: -64) NOTE: The H.263 MMX quantizer cannot handle positive biases (set vfdct=1 or 2), the MPEG MMX quantizer cannot handle negative biases (set vfdct=1 or 2). HINT: A more positive bias (-32 − -16 instead of -64) seems to improve the PSNR.
Noise reduction, 0 means disabled. 0−600 is a useful range for typical content, but you may want to turn it up a bit more for very noisy content (default: 0). Given its small impact on speed, you might want to prefer to use this over filtering noise away with video filters like denoise3d or hqdn3d.
Quantizer noise shaping. Rather than choosing quantization to most closely match the source video in the PSNR sense, it chooses quantization such that noise (usually ringing) will be masked by similar-frequency content in the image. Larger values are slower but may not result in better quality. This can and should be used together with trellis quantization, in which case the trellis quantization (optimal for constant weight) will be used as startpoint for the iterative search.
Use custom inter matrix. It needs a comma separated string of 64 integers.
Use custom intra matrix. It needs a comma separated string of 64 integers.
experimental quantizer modulation
experimental quantizer modulation
intra DC precision in bits (default: 8). If you specify vcodec=mpeg2video this value can be 8, 9, 10 or 11.
Close all GOPs. Currently it only works if scene change detection is disabled (sc_threshold=1000000000).
Control writing global video headers.
Same as vglobal for audio headers.
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