TDecimate is part of TIVTC. It is a decimation filter intended to remove duplicates from a video stream. It supports a couple types of operation which include M-in-N decimation and an arbitrary framerate decimation scheme that can support ratios not achievable with M-in-N. It also includes special handling for hybrid material such as blend decimation (for a single frame rate solution) or vfr via mkv using a timecodes file.
TDecimate(int mode, int cycleR, int cycle, float rate, float dupThresh, float vidThresh, float sceneThresh, int hybrid, int vidDetect, int conCycle, int conCycleTP, String ovr, String output, String input, String tfmIn, String mkvOut, int nt, int blockx, int blocky, bool debug, bool display, int vfrDec, bool batch, bool tcfv1, bool se, bool chroma, bool exPP, int maxndl, bool m2PA, bool denoise, bool noblend, bool ssd, int hint, PClip clip2, int sdlim, int opt)
mode - Sets the mode of operation. Possible settings: Mode 0 = Straight M-in-N decimation. TDecimate will examine each set of N frames and decimate the M most similar frames. The values of M and N are controlled via the cycleR and cycle parameters. Blend decimation of video (30p) is supported in the this mode (hybrid = 1), as well as blending of 24p into 30p (hybrid = 3). Mode 1 = Exactly like mode 0, except instead of decimating the M most similar frames, frames are decimated from the longest remaining strings of duplicates. The duplicate detection uses the dupThresh parameter. This mode is the correct type of decimation for anime and other sources where frames are repeated 2, 3 or 4 times in a row, and also supports blend decimation of video (30p) with hybrid = 1, as well as blending of 24p into 30p (hybrid = 3). Mode 2 = This mode uses a separate decimation algorithm that can achieve any arbitrary framerate. It is useful when you cannot achieve the desired framerate with M-in-N decimation. The output framerate for this mode is set using the "rate" parameter. The maxndl parameter can be used to tweak behavior on sources with uneven duplicate distribution. No hybrid handling can be used in this mode! This mode's output will be slightly different if you run it with a metrics input file (created on a previous pass in mode 4 for example) that lets it analyze the entire video at the very beginning than if you run it straight and let it analyze the video as it goes. Generally the differences will be small, but the 2 pass method (i.e. full analysis from an input file) will generally produce a smoother result. The m2PA parameter can be used to force the one pass version of mode 2 to produce the same results as the two pass version by reading ahead in the stream as much as is required (the one pass version limits the read ahead to 100 frames max). Mode 3 = This is a one-pass vfr for mkv with timecodes output mode. Hybrid must be set to 2 in this mode! It uses M-in-N decimation and cycleR must be set to 1! The type of decimation that is used on film sections (most similar or longest string) is controlled via the vfrDec setting. For this mode to work all access must be linear from start to finish... an error will be thrown if non-linear access is detected. Since vfw needs to know the # of frames before processing starts this mode does not change the # of frames and simply pads the output as needed with black frames. The last actual frame will be recorded as a comment at the end of the mkv timecodes file, and will be reported on the padded frames as well once at least 300+ extra frames are returned. If the se option is set to true, then TDecimate will throw an error once the 306th extra frame is reached, stopping processing and alerting the user. If your gonna be around when its done and not doing batch encoding this option can save you some time. The name and path of the mkv timecodes file to output is set using the mkvOut parameter. Mode 4 = Metrics output. No decimation is done, but metrics are calculated allowing for the output, display, or debug options to be enabled and outputting of the metrics for later use. (first pass for two pass mkv vfr using mode 5) Mode 5 = This is similar to mode 3 (mkv vfr, and requires hybrid=2 and cycleR=1), but as part of a two pass process. It requires a complete input file (obtained via the output parameter on a previous pass), and a complete tfmIn file (see the batch option for a way around these requirements). The advantages of this mode over Mode 3 are that it does not require linear access (seeking is supported), it uses the conCycleTP parameter instead of the conCycle parameter which allows for values greater than 2, and it will have a correct frame count with no padded frames. As of version 0.9.11.8 of TDecimate, an input and tfmIn file are no longer required for mode 5. If an input file is not specified then a value of ULLONG_MAX-1 (the maximum value tdecimate has) is assigned to all metrics. Likewise, if a tfmIn file is not specified then all matches are assigned as 'c', not combed, and not a d2v duplicate. Mode 6 = This is for doing 120fps->vfr w/ timecode file. It requires a complete metrics input file generated via mode 4 on a previous pass. It will decimate bit for bit identical frames only. All decimation will be into one of the following frame rates: 119.880, 59.940, 39.960, 29.970, 23.976. Mode 7 = This mode is similar to mode 2 in that it uses a decimation algorithm that can achieve any arbitrary framerate. However, it operates quite differently from mode 2. It is useful for when you cannot achieve the desired framerate with M-in-N decimation and cannot afford to go with two-passes in mode 2 (in which case mode 7 will usually give better results if the duplicate distribution is at least somewhat consistent). The output framerate for this mode is set using the "rate" parameter. It also uses the "dupthresh" and "vidthresh" parameters... dupthresh sets a threshold such that any frames with difference values under dupthresh are considered duplicates, and vidthresh sets a threshold such that any frames with difference values above vidthresh are considered non-duplicates. Frames with difference values inbetween dupthresh and vidthresh are classified as similar unless they represent a descernable local minimum or maximum in the difference values string. By default dupthresh is set to 0.5 and vidthresh is set to 4.0 (they use the usual 0 to 100 normalized scale). Default: 0 (int) cycleR - Sets the "M" for the M-in-N decimation modes. In other words, setting this to 1 means 1 frame in every cycle frames will be dropped. This setting can be anything in the range 1 to (cycle-1). It must be less than the value of the cycle setting! *NOTE: all hybrid handling options only support cycleR = 1. So if hybrid > 0 this value must be set to 1! Default: 1 (int) cycle - Sets the "N" for the M-in-N decimation modes. In other words, setting this to 5 means cycleR frames in every 5 frames will be dropped. This setting can be anything in the range 2 to (number of frames in video). It must also be greater than the cycleR setting. Default: 5 (int) rate - This sets the output frame rate when using mode = 2 or 7. Frames will be dropped so that this frame rate is acheived while keeping audio/video sync as close as possible. This must be less than the input frame rate. Default: 23.976 (float) hybrid - Controls how or if video sections (30p) should be dealt with. Possible settings: 0 - no handling 1 - blend decimation of 30p sections into 24p and leave 24p untouched (modes 0 and 1) 2 - vfr via mkv w/ timecodes file output (modes 3 and 5) 3 - blend conversion of 24p sections into 30p and leave 30p untouched (modes 0 and 1) * The hybrid option is not used when mode = 2 or mode = 4, and hybrid > 0 is only currently supported for cycleR = 1! Default: 0 (int) vfrDec - Sets the type of decimation to use for film sections when using modes 3 and 5. Possible settings: 0 - drop most similar frame in cycle 1 - decimate from longest string of duplicates Default: 1 (int)
dupThresh - This sets the threshold for duplicate detection. This setting is used in mode 1 and also in modes 3 and 5 if vfrDec = 1. If the difference metric for a frame is less than or equal to this value then it is declared a duplicate. NOTE: metrics will be slightly different between YV12 and YUY2 processing if chroma=true... the metrics have been normalized so they should match closely, but on average the YUY2 metrics tend to be slightly higher (5-10%) than the YV12 metrics for the same frame when chroma=true. When chroma=false YV12 and YUY2 metrics will be the same, however chroma=false metrics will be higher than chroma=true metrics so if you set chroma=false be sure to account for this. This value is a % of maximum change for a block defined by the blockx and blocky values.... so 1.1 means 1.1% of maximal possible change. When in mode 7, dupThresh is used to set a threshold below which frames are considered to absolutely be duplicates. Use display=true to see what the calculated metric values for the frames are and what the threshold values (translated into unnormalized values) are. Default: 1.1 (if chroma = true) (float) -- modes 1, 3, 5 1.4 (if chroma = false) 0.4 (if chroma = true) (float) -- mode 7 0.5 (if chroma = false) vidThresh - This setting is used for detecting video sections (30p) based off frame metrics when hybrid > 0. If all frames in a cycle have metrics above this threshold then the cycle is declared video metrics wise. This setting is similar to dupThresh, but should be set slightly higher if your vidDetect setting is set to 1 and not 3. If you know that your source has a lot of video sequences then set this lower vs if you know your source is pure film then you can set this really high to prevent any possible misdetections. This value is a % of maximum change for a block defined by the blockx and blocky values.... so 1.1 means 1.1% of maximal possible change. When in mode 7, vidThresh is used to set a threshold above which frames are considered to absolutely be non-duplicates. Use display=true to see the unnormalized threshold values and the frame difference values. Default: 1.1 (if chroma = true) (float) -- modes 1, 3, 5 && hybrid > 0 1.4 (if chroma = false) 3.5 (if chroma = true) (float) -- mode 7 4.0 (if chroma = false) sceneThresh - Sets the threshold for detecting scene changes when using blend decimation for video sections (hybrid = 1) or blend conversion for 24p->30p (hybrid = 3). This value is a % of maximum change for the luma plane. Good values are between 10 and 15. Must be in the range 0 to 100. Default: 15 (float) vidDetect - This sets what is required for single cycle video detection when hybrid > 0. Whether a single cycle alone is enough or whether two consecutive cycles or more must be detected as video is controlled via the "conCycle" and "conCycleTP" parameters. Video detection via frame matches: (Labeled Type A) i.) The matches that were used by TFM do not indicate that there are duplicates in the cycle Video detection via metrics: (Labeled Type B) i.) All frames in the cycle have metrics above vidThresh. Video detection via absence of local minima: (Labeled Type C) i.) All frames in the cycle have metrics that are within 150% of each other (1.5x) and within 2.0 (abs value difference) of each other. The maximum metric value within the cycle must greater than or equal to 0.3. How these types of information are used as a whole to determine video sections is determined by vidDetect. Each vidDetect setting has a condition that if met will result in the current cycle being detected as video. (refer above for the A and B labels). Please note that ovr (overrides) overrules vidDetect! 0 - A (if matches indicate video then consider it video) 1 - B (if metrics indicate video then consider it video) 2 - A or B (if either matches or metrics indicate video then consider it video) 3 - A and B (if both matches and metrics indicate video then consider it video) 4 - A and (B or C) (if matches indicate video and metrics indicate video or matches indicate video and there are no local minima consider it video) Default: 3 (int) conCycle - conCycle sets the required minimum # of consecutive cycles detected as video for any section to be considered video when hybrid > 0. Meaning, if conCycle is set to 2, and a single cycle is detected as video but both the cycle before it and after it are detected as film then that cycle will be considered film as well. If conCycle had been set to 1 in the previous example then the standalone video cycle would have been consider video. This setting is used in all cases except two pass mkv vfr (mode 5) where conCycleTP is used instead! The difference is conCycle is limited to a maximum value of 2 while conCycleTP has no upper limit. Possible values are 1 or 2. default: 1 if vidDetect = 3 (int) 2 otherwise conCycleTP - This is the same as conCycle, but is used in mode 5 (two pass) and allows for any value (not just 1 or 2) and has no upper limit. Default: 1 if vidDetect = 3 (int) 2 otherwise nt - Sets the noise threshold used when calculating difference metrics. If the abs() difference between two pixels is less than or equal to this value, then the difference is considered 0. This can help lower the metrics of actual duplicate frames thus widening the difference between dups and non dups making it easier to set correct thresholds. Avoid setting this value to high or very similar objects moving over one another will start to not be detected etc... Good values are in the range 1-2. For clean video using a value of 0 seems to work best. Default: 0 (int) blockx - Sets the x-axis size of the blocks used for metric calculations. Larger blocks give better noise suppression, but also give worse detection of small movements. Possible values are any power of 2 from 4 up to 2048 (4, 8, 16, 32, ... 2048). Default: 32 (int) blocky - Sets the y-axis size of the blocks used for metric calculations. Larger blocks give better noise suppression, but also give worse detection of small movements. Possible values are any power of 2 from 4 up to 2048 (4, 8, 16, 32, ... 2048). Default: 32 (int) batch - This setting is intended to be used only with mode 5. Basically, it sets some arrays to fake values and disables a few checks allowing for an avisynth script with tdecimate(mode=5, ...) to be loaded when the tfmIn and input files do not have any entries. This is useful and needed for setting up a two pass system in vdub's job control. i.e. you make the first pass and second pass scripts, and then set up both to encode in vdub's job control. NOTE: if you set batch = true and the tfmIn and input files do not have entries for all frames then you will get borked output! As of v0.9.12.3, batch also disables crc checking when using an input file (this applies to all modes), and it will only set arrays to fake values if mode is set to 5. true - enables fake values and disables checks false - doesn't Default: false (bool) tcfv1 - Sets the type of timecode format to use for mkv timecode files when they are created in modes 3 and 5. The two format types are those defined and used by mkvtoolnix. verion 1 sets the framerate for frame ranges while version 2 gives the timecode for each frame in milliseconds. See the mkvtoolnix documentation for more info about the two formats. true - use version 1 false - use version 2 Default: true (bool) se - Only used when in mode 3. It will cause TDecimate to throw an error once the 306th padded frame is reached, alerting the user that it has finished, so that time wont be spent processing unneeded frames. This option should not be used when doing batch encoding or something similar, because the error will usually pop-up a window which requires the user to click, thus it would stop any subsequent processing as well. true - stop early (throw error) false - don't Default: false (bool) chroma - Sets whether or not chroma is considered when calculating frame difference metrics. Setting this to false can give a speed up... it a quality vs speed setting (though in some cases setting chroma=false can improve operation). true - consider chroma false - don't Default: true (bool) exPP - Set this to true if you're using a tfmIn file, have tfm set to PP=1, and are using a separate filter (such as tdeint) to do post-processing based on tfm's combed frame hints. If you don't set this to true when PP=1 in tfm, then tdecimate assumes the interlaced frames marked in the tfmIn file are not being deinterlaced... if this is not the case (they are actually being deinterlaced by a separate filter) then those frames will not be handled correctly. Default: false (bool) maxndl - This setting is used only with mode 2 and stands for "max non-duplicate length". It tells TDecimate the maximum consecutive number of non-duplicates. This info is used when planning the decimation strategy. In normal cases, when duplicates are evenly distributed in the video, it should not be necessary to set this. Only in cases where the length indicated by the decimation ratio is too short should this need setting. For example, say we have the following pattern in a video: 5 5 7 7 2 where the numbers indicate how many frames there are between duplicates. In this case we want to remove 5 in every 26 frames. This decimation ratio (5/26) would indicate that there is one duplicate in every 5.2 frames (5/26 = 1/5.2). Obviously, as the pattern above shows, this is the not the case as there are runs of up to 7 without a duplicate. So we would need to set maxndl to 7. Another example would be decimating a 59.94fps video to 23.976. This ratio would indicate one duplicate in every 1.667 (5/3) frames. However, if the video has sections where two non-duplicates are back to back then maxndl would need to be set to 2 to correctly handle it. EXTRA INFORMATION: While maxndl stands for "max non-duplicate length", it is actually more like a trade off between maintaining video sync and producing a smooth result. The larger maxndl is the more the decimation can be non-uniformly spread throughout the video, which helps the smoothness of the result in cases where duplicates are not evenly spread. Anyways, experiment with increasing maxndl and see what happens. Possible settings for maxndl are any integer greater than 0. Default: not set (int) m2PA - Will override the default read-ahead maximum of 100 for mode 2. This will allow the one pass mode (metrics not available from an input file) to produce the same results as if the metrics were available. **NOTE: the cycle size could very well be in the 1000's or 10000's, so there is the possibility setting m2PA=true could mean the processing will stall for quite some time (5-10 minutes or more) when a new cycle starts!!! Please check the largest cycle size that will be used using debug=true before setting m2PA=true! true = override the default maximum false = don't Default: false (bool) noblend - Even with hybrid=0 there is a special case when tdecimate will use blend decimation, and that is when it detects two duplicates in a cycle, cycleR=1, and neither duplicate is next to a scenechange. In such cases tdecimate will drop one of the duplicates and replace the other with a blend of its neighbors. The "noblend" parameter is used to disable this so that no blending is ever done when hybrid = 0. true - no blending when hybrid = 0 false - use blending in the two duplicate case Default: true (bool) denoise - Sets whether or not to denoise frames prior to doing difference metric calculations. This can greatly improve metrics for noisy sources (i.e. stabilize duplicate frame metrics and make it easier to tell the difference between duplicates and non-duplicates). It also works very well for sources with lots of dot-crawl because the denoising effectively cancels all dot-crawl, whereas the dot-crawl would usually inflate difference values of duplicates. Using denoising will slow things down somewhat, but it is MMX optimized and pretty fast. true - use denoising false - don't Default: false (bool) ssd - Controls whether the metrics are calculated as SAD (sum of absolute differences) or SSD (sum of squared differences). true - use ssd false - use sad ** Prior to v0.9.11.0 of tdecimate SAD was always used... and it is almost always best for TDecimate's purposes and the default thresholds for dupThresh, vidTresh, and sceneThresh are based on SAD values. Default: false (bool) hint - Enables or disables reading of tfm's hints. The information in the hints can effect tdecimate's decisions (i.e. in mode 0 it can lead to dropping a frame other than the lowest metric'd frame in a cycle). Hint information contains match used, combed vs. progressive, d2v rff info... that info is also used for hybrid detection (depending on the vidDetect setting). true enables reading, false disables. If not explicitly set by the user, tdecimate checks if hints are present in the stream on load and sets the 'hint' parameter accordingly. Default: auto-detect on load (bool) clip2 - Allows specification of a second clip from which to take frames. Metric calculation and decimation are still done on the input clip, but the frames that tdecimate returns are from clip2. Clip2 must have the same number of frames are the input clip and be in YUY2 or YV12 colorspace (it does not have to have the same colorspace as the input clip). Default: null (PClip) sdlim - When using mode 0, 1, or 3, with cycleR > 1, sdlim sets the minimum distance in frames between removed duplicates. For example, with sdlim=2, tdecimate will not remove any frame that is within two frames of a frame already marked for decimation. Frames are marked for decimation in order from lowest to highest difference metric within the current cycle. The maximum value for sdlim is governed by the following equation: (sdlim+1)*(cycleR-1) < cycle When using longest string decimation (mode 1 or mode 3 w/ vfrdec=1), sdlim will only come into play if the number of frames with difference metrics < dupthresh is < cycleR-1. It is possible to use an sdlim value that could result in tdecimate not being able to mark a full cycleR worth of frames. In this case, if sdlim is positive (i.e. > 0), then tdecimate will mark as many frames as possible with the given sdlim value and then simply mark the remaining number frames without regard to how close they are to already marked frames. If sdlim is negative (i.e. < 0), then tdecimate will decrease sdlim for that cycle by 1 and then start over from scratch marking frames. This process of decreasing sdlim will continue until a value that allows a full cycleR worth of frames to be marked is found. When sdlim is given as a negative value, the absolute value is actually used. The sign is simply used to determine which method of dealing with the "unable to mark a full cycleR worth of frames" scenario is used. Default: 0 (int) opt - Controls which optimizations are used. Possible settings: 0 - use c routines 1 - use mmx routines 2 - use isse routines 3 - use sse2 routines 4 - auto detect Default: 4 (int)
File input/output parameters
ovr - Sets the name and path to an overrides file. An overrides file can be used to force ranges of frames to be considered film or video and to specify drop frames or decimation patterns over ranges of frames. For more info on using an ovr file see the OVERRIDES section at the bottom of this file. Mode 7 does not currently support using an overrides file. Default: "" (String) output - Sets the name and path to an output file. The output file will include all metrics caculated. Each line will include a frame number, plus the difference metric, and the scene change metric. This file can be used for input (via the input parameter) on another pass to avoid having to recalculate the metrics or for the mode 5 two pass vfr support. Default: "" (String) input - Sets the name and path to a metrics file to use as input. This file should have been created with the "output" parameter on a previous pass. Default: "" (String) tfmIn - Sets the name and path to an output file from TFM. This option is useful when using hint=true and a tfm output file has been generated on a previous pass. This option allows TDecimate to get info from tfm without having to check frames for hints, which can result in a very large speed up for large cycle sizes (even small cycle sizes should get a noticable speed increase). The only case where a tfmIn file is absolutely required is in mode 5! Default: "" (String) mkvOut - This sets the name and path for the mkv timecodes file that is generated in modes 3 and 5. Default: "" (String)
debug - Enabling this will make TDecimate output information about its internal states and decisions via OutputDebugString(). You can use a program called DebugView from System Internals: http://www.sysinternals.com/ntw2k/utilities.shtml to view this output. This can be useful in setting thresholds and seeing what is happening. To find out exactly what all it shows you'll have to use it ;) When mode = 2 and debug=true, TDecimate will spit out the cycle sizes for the series of M-in-N decimations. That output will look something like this:  mode2_cfs 0 = 7  mode2_cfs 1 = 7  mode2_cfs 2 = 14  mode2_cfs 3 = 56  mode2_cfs 4 = 392 The last "mode2_cfs # = ##" line shows the largest cycle size being used (the number after the "="). So if you set m2PA=true, and the metrics are not available from an input file, TDecimate will be reading that ## frames (392 in the above case) ahead in the video stream, and will have to process those many frames at each cycle boundary! default: false (bool) display - Outputs almost exactly the same information as debug, but draws it on the actual frames in the upper left hand corner. This is usually easier to read and use then the debug output. To find out exactly what all it shows you'll have to use it ;) default: false (bool)
An overrides file can be used to manually set drop frames, declare video/film sections, or specify decimation patterns over ranges of frames. specifying video cycles: To specify a range of frames for TDecimate to consider video... first, enter the starting frame number, then put a comma (","), then enter the ending frame number, and finally put a "v" as the specifier. This range is inclusive, meaning that the starting and ending frame numbers will be counted as video! Remember that video sections are only considered when hybrid > 0! example: 10,334 v specifying film cycles: Same as video but use "f" as the specifier. Doing this will only make a difference when using hybrid > 0 and detecting video sections. In all the other modes everything is considered film to begin with. example: 10,334 f specifying drop frames: To specify a drop frame enter the frame number you want to drop and put a "-" specifier. If you manually specify more than cycleR drop frames for one cycle then the ones that come first chronologically will be used. If using mode 2, and not an M-in-N decimation mode, the same restriction applies, but instead of cycleR being the limiter it is an internally computed number. example: 226 - specifying a decimation pattern: Use the drop frame specifier along with keep frame specifiers (+) as place holders. example: 10,334 +-+++ In this example every 2nd frame will be dropped starting at frame 10 and going to frame 334. EXTRA NOTES: 1.) If you specify overlapping entries then the entry that comes last in the ovr file will be used. 2.) All frame number entries correspond to the frame numbers in the input clip (i.e. the input into TDecimate). They do not correspond to the frame numbers after decimation (this is the cause of a lot of headaches). 3.) You can only give cycleR drop frames per cycle. If you specify more than that, then the first cycleR worth specified will be used.