Lzma2 dictionary size. 0. xz is currently LZMA2, which is an extension on top of the orignal LZMA to fix a few practical issues, like adding support for flushing the encoder (equivalent to zlib's Z_SYNC_FLUSH), which isn Specifies dictionary size for compression. 35: AES code and SFXs modules were included to SDK. Now back to my original question: In my case solid block size didn't produce any noticeable results. If very high compressor and decompressor memory usage is fine, and the file being compressed is at least several hundred megabytes, it may be useful to use an even bigger dictionary Aug 1, 2022 · I'm assuming (based on my previous tests with gzip, bzip2 and LZMA2 in xz and 7z) that LZMA2 is simply, generally "the best" for compressing rather "noisy" data. Note also that it's better to use 2 threads for LZMA/LZMA2. The sum lc + lp must be at most 4. Two threads work faster than 1 thread for LZMA, and it still uses same memory amount as 1 thread. Maybe you can try some external program for long range deduplication before lzma compression. ValidHeader checks for a valid LZMA file header. Word size: 273. Word Size: 273 becomes -mfb273. Compression Method: LZMA2 becomes -m0=LZMA2. For LZMA2, it is harder to recover them, so 7-Zip shows only dictionary size. bin file by using: 1. I want to zip and upload a 16gb file I would like to know the best way to compress so I can reduce the size significantly before uploading. Default values for LZMA are 24 (16 MB) in normal mode, 25 (32 MB) in maximum mode (-mx=7) and 26 (64 MB) in ultra mode (-mx=9). The dictionary size has to be significantly bigger than any individual file to allow LZMA2 to take full advantage of the similarities between consecutive files. Jpeg compression. The dictionary of size m is actually just the memory of the last seen bytes of the uncompressed data, capped by a limit of m. cpu threads = 2. . After that comes a 4-byte CRC-32/IEEE checksum of that block header. The minimum is 4 KiB. Dec 13, 2014 · 7zip LZMA2 compression with dictionary size of 1536Mb; WinRar "solid" file; 7zip WIM file; I had 10 folders with different versions of a web site (with files such as . lp: Number of literal position bits. 06: Some speed optimiztions in LZMA/LZMA2 code. It uses a parallel buffered radix matchfinder and some optimizations from Zstandard. The same (or bigger) dictionary size is required for decompressing that was used when compressing, thus the memory usage of the decoder is determined by the dictionary size used when compressing. The LZMA2 dictionary is allocated once the required size has been parsed from the stream headers. It really depends on the data you're compressing and the algorithm used. ) with a total size of 1Gb (100Mb average per folder). Hello. Dictionary Size, Word Size and Solid Block size it is basically impossible to predict which options would be most optimal, even if we knew exactly what content you are trying to compress. Dictionary Size: 1024MB becomes -md=1024m. h. 04 help - cannot see 'level' - can see method -m but not 'ultra'. // Ultra. This implementation supports only 16 bytes less than 2 GiB for raw LZMA2 streams, and for . VHD. Dictionary size and match finder (mf) together determine the memory usage of the LZMA1 or LZMA2 encoder. 5304. Naturally, I could look at the data and identify top-level folders that are specifically large, and group the data in like maybe ~2-4 TiB chunks. The entire output buffer must be allocated with a fixed size -- however, callers are able to query the required size; The XZ file must be "solid", i. 5 GiB. lzma file format uses simple header, it supports only LZMA method, and it supports only one file per archive. ja, the total size of each file compressed discretely is 7,942,886 bytes. At -6 and lower, the amount of memory wasted is usually low enough to not matter. Minor speed optimizations in LZMA/LZMA2 compressing. If LZMA2 is set to use only such number of threads required for one chunk, it doesn't split stream to chunks. Decompression speed of LZMA and LZMA2 archives in ARM64 versions for Mac OS and Linux improved by 20-60%. And, I forgot that in my previous post, 7-Zip sets this mode by default, so you do not need to specify this switch explicitly. How can I convert this settings into command? Here are the results: // Manual Compression (see the image above) Compressed Size: 12,647,451 bytes. sql, etc. Email for Java - API LZMA is default and general compression method of 7z format. 3MB where N is number of files. Dictionary size has the biggest effect on compression ratio. Variable dictionary size (up to 4 GB) Compression speed: about 1 MB/s on 2 GHz CPU Decompression speed: about 10-20 MB/s on 2 GHz CPU Small memory requirement for decompression (depends from dictionary size) Small code size for decompression: about 5 KB Supports multi-threading and P4's hyper-threading Dictionary size and match finder (mf) together determine the memory usage of the LZMA1 or LZMA2 encoder. eg. A larger dictionary size can provide a better compression ratio at the expense of compression speed and memory requirements. 47. 11: PPMd support. pb: Number of position bits; must be at most 4. a)Archive format :7z b)compression - level = 1-Fastest c)compression method = LZMA2 d)Dictionary size = 256KB e)Word size = 32 f)Solid block size = 32MB g)Number of CPU threads = 4/4 h)Memory usage compression = 80% i)Split by volume = 20M Dictionary size and match finder (mf) together determine the memory usage of the LZMA1 or LZMA2 encoder. Just looked at 7z 16. 它使用类似于 LZ77 的 字典编码 (英语:Dictionary coder) 机制,在一般的情況下壓縮率比 bzip2 為高,用於壓縮的 Mar 10, 2013 · dict_size: Dictionary size in bytes. If I set the compression to Ultra (highest posible) and set 1 thread it takes 6 seconds. It can still be changed in the options, but the meaning of the value is different. 1 MiB is probably the maximum reasonable dictionary size for in-kernel use (maybe more is OK for initramfs). Typically a good value is 2-4 times the size of the LZMA2 dictionary or at least 1 MiB. Dictionary size: 1024MB. try -snl switch. lzma. 9 Feb 6, 2017 · What 7-zip lzma/lzma2 command line parameters get the fastest decompression? Needs to be compatible with -sfx. 68-1_amd64. Jun 22, 2023 · when I am using 7zFM. 7-Zip is free software with open source. The LZMA2 algorithm allows dictionaries up to one byte less than 4 GiB. Typically a good value is 2–4 times the size of the LZMA2 dictionary or at least 1 MiB. exe to split a file that is 6GB in size with the following parameters. Replaced the callbacks for writing and progress with timeouts and new functions to gain direct access to the dictionary buffer and the compressed data buffers. -t7z 7z archive -m0=lzma lzma method -mx=9 level of compression = 9 (Ultra) -mfb=64 number of fast bytes for LZMA = 64 -md=32m dictionary size = 32 megabytes -ms=on solid archive = on Typical dictionary size is from 64 KiB to 64 MiB. Jun 22, 2016 · Now let's play with word and dictionary size for ultra compressed LZMA2 files Word size 273 / dictionary 64MB: 8,8 MB; Word size 273 / dictionary 128MB: 8,8 MB; Final conclusions 7zip, 7z, LZMA2, or however you name it, is the way to go. // LZMA2. The main features of LZMA method:. The maximum for compression is currently 1. Memory usage for LZMA Apr 5, 2024 · 7-Zip is free software with open source. Review the memory requirements listed in the Compression topic before Apr 3, 2024 · func ValidHeader added in v0. 7z -mx9 -aoa. I don't want the size to be reduced. 826 7 13. Some bugs were fixed. Big word size parameter can significantly increase Jan 14, 2014 · The only supported filter is LZMA2 compression; Maximum dictionary size of 32Mb, enough for the command xz -8 but not xz -9 (this is currently configurable with a pref, but needs to be standardized) The only supported integrity checks are CRC32, CRC64 or none; Alternative container formats could have been: 1 day ago · Compression filters support the following options (specified as additional entries in the dictionary representing the filter): preset: A compression preset to use as a source of default values for options that are not specified explicitly. From what I understand, the best options would be: Archive format - 7zip (Best format) Compression level - Ultra. 7z a xx -mx filename works but no mention of ultra, or lzma2. If the allocation fails, xz_dec_run() will return XZ_MEM_ERROR. lzma files. Jul 20, 2021 · 7-Zip 21. 05: Some speed optimiztions in LZMA/LZMA2 code. ja is 9,783,749 bytes. What's the best compression setting for winrar or 7zip to zip a large file? The default size is three times the LZMA2 dictionary size or 1 MiB, whichever is more. deb Dictionary size and match finder (mf) together determine the memory usage of the LZMA1 or LZMA2 encoder. This should be between 4 KiB and 1. Compressed Size: 14,237,515 bytes . 4097, 50000, …), Will it makes negative affect to LZMA2 compress/decompress ratio and speed? Dictionary size and match finder (mf) together determine the memory usage of the LZMA1 or LZMA2 encoder. method: lzma2. ) . However, the result of both are different despite I'm using the same "Properties Jul 11, 2013 · Yeah for some reason it is hard to do that with code. The decompressor already supports dictionaries up to one byte less than 4 GiB, which is the maximum for LZMA1 and LZMA2 stream formats. Jun 16, 2010 · Description: The maximum number of threads LZMA2 can use. Archive format:. Mar 7, 2017 · But if we produce a 131,072 byte dictionary by training it on all files within omni. The 1024 Mb dictionary limit is a legacy of configuration code from Zstandard, which accepts only logarithmic sizes. : Multi-call mode. The most of the code is under the GNU LGPL license. Word size. Apr 18, 2024 · "21 01" means that that base compression filter is LZMA2 and its properties occupy one byte. 1. " Then click on the "Compression" tab and check the box next to "LZMA2. Variable dictionary size (up to 4 GB) Compression speed: about 1 MB/s on 2 GHz CPU Decompression speed: about 10-20 MB/s on 2 GHz CPU Small memory requirement for decompression (depends from dictionary size) Small code size for decompression: about 5 KB Supports multi-threading and P4's hyper-threading Well best depends on your use case, but I personally use LZMA2 (same as xz), 32MB dictionary size, 64 word size, leave the solid block size as is. 5 GiB (inclusive). Archive size depends quite non-monotonically of it. Mar 9, 2021 · Management of memory and options. Using it, I got 20,518,802B in about 3 minutes. 01: Some changes in LZMA2/xz multithreading code for compressing. I'll now show how to decipher the Method column for a given file. In WinXP 32bit with a Core i5 (dual core) and 4GB RAM, I'm trying to create an . Key Operation mode: -z, --compress Force compression -d, --decompress Force decompression -t, --test Test compressed file integrity -l, --list List information about files Operation modifiers: -k, --keep Keep (don’t delete) input files -f, --force Force overwrite of output file and (de)compress links -c, --stdout Write to standard output and Oct 27, 2020 · For LZMA, most parameters are stored explicitly in the stream, so they are shown if their values differ from the default ones. I have compressed a 117073-KB file with console 7-Zip 20. It allows only dictionary sizes of 2^n or 2^n+2^ (n-1) with n >= 10 or 2^32-1. mode: MODE_FAST or MODE_NORMAL. : a single block (with a single dictionary/properties reset) The LZMA2 property byte must indicate the LZMA properties lc = 3, pb = 2, lc = 0 Jul 31, 2023 · For ". After that was 7-Zip 9. 03 beta was released. The xz format will employ LZMA2 which consists of extensions on top of LZMA, in the xz utils maintainer's words: "The primary compression algorithm in . I will try to set the word size on my program somehow and let you know – The default size is three times the LZMA2 dictionary size or 1 MiB, whichever is more. Memory (RAM) usage for LZMA compression is about 11 times more than dictionary size and strongly dependent on the number of CPU cores on the machine. 7Z *. g. LZMA2” of the XZ spec for the formula). 7z May 5, 2019 · Improved calculation of the match buffer size. Try several values, e. Going for an even higher word size also System::Security::SecurityElement Member List - Aspose. exe works only with . 7z file format uses complex headers, it supports different methods (including LZMA), and it supports big number of files in archive. LZMA2 is a modified version of LZMA that offers a better compression ratio for uncompressible data (random data expands about 0. + * + * Multi-call mode with preallocated dictionary (XZ_PREALLOC): dict_max bytes + * of memory is preallocated for the LZMA2 dictionary. ) you need to create a context: fast-lzma2. 7z a -t7z Files. Sep 13, 2017 · Word Size: Like Dictionary Size, the bigger the better in theory, but this is dependent on what kind of files you’re compressing so there is no universal rule. If I then shift the word size to 786 MB it takes 21 seconds so maybe that is the problem. I want to combine many files into one file, without losing any quality. dict_size: Dictionary size in bytes. js, . ) tried to generate in python using following code. Enter the length of words, which will be used to find identical sequences of bytes for compression. This limitation is due to Java using signed 32-bit integers for array indexing. Run the compiler on x64 system. The codec uses much less additional memory per thread than standard LZMA2. LZMA (英語: Lempel–Ziv–Markov chain algorithm )是2001年以来得到发展的一个 数据压缩 算法,它用于 7-Zip 归档工具中的 7z 格式和 Unix-like 下的 xz 格式。. 4. xz files the maximum is 1. JPEG images are inherently hard to compress because their format already incorporates a simple but effective compression scheme. Issue: But i am not getting desired result and compression gets stuck at 14%, is there is a issue in my command or what is command should i In userspace, LZMA2 is typically used with dictionary sizes of several megabytes. Compression Level: Ultra becomes -mx9. Increasing word size did produce some results. For LZMA, big word size usually gives a little bit better compression ratio and slower compression process. Three NUL bytes pad to a double-word boundary. The name of method/filter is shown first, its parameters follow, separated The minimum is 4 KiB. It is waste of memory to use a dictionary bigger than the size of the uncompressed file. xz archive from a 266MB log file using 7-Zip (GUI) on the "ultra" compression level (method: LZMA2, dictionary size: 48MB, word size: 64, CPU threads: 4/4) with calculated memory for compressing: 1680MB, and for decompressing: 50MB. The maximum value for dictionary size is 1536 MB, but 32-bit version of 7-Zip allows to specify up to 128 MB dictionary. In userspace, LZMA2 is typically used with dictionary sizes of several megabytes. 9. Compression method - LZMA2 (Best compression method) I was wondering about the following options: Dictionary size - I don't know what this option changes, nor what would be the best setting. Aug 12, 2020 · Yes, you need each of chunk size, solid block size and dictionary size slightly larger than file size. 7z" format I see that in the "Method" column in 7-Zip there are values like "LZMA2:20", "LZMA2:24", etc, I try to match them with dictionary sizes and it seems to work, although explicit columns in 7-Zip like "dictionary size" would make it easier to understand Jul 30, 2009 · For best compression ratio: format: 7z. The archive is correct, but it does not delete all the files after compression. css, . Nov 29, 2010 · I noticed that All dictionary size value appeared in XZ head files are exactly power of two. The Jpeg compression method is designed to compress JPEG images. /*= Compression context. Award. Ultra compression when using 7Zip, the compression algorithm LZMA2 is best, alternatively LZMA with a 4GB dictionary size. LZMA2 and Ultra are the only two settings you need to care about. * When compressing many times, it is recommended to allocate a context just once, * and re-use it for each successive compression operation. Including the dictionary, the total size is 8,073,958 bytes, 1,103,452 bytes smaller than non-dictionary compression! (The zlib-based omni. " Click on OK and then click on OK again. You need about 12*DicSize of virtual memory to use LZMA and LZMA2, so it is usually impossible to use DicSize above 1GB. Jun 5, 2013 · Compression Method: LZMA2. We would like to show you a description here but the site won’t allow us. e. So for your usage, m := n will be optimal to make the best of the LZMA compression in a standalone way. Header. By default it uses the same dictionary size as 7-Zip, resulting in output that is larger by about 1%-5% of the compressed size. Jun 20, 2019 · Hans-Martin Mosner. I tried to generate lzma file of a 16kb *. func ValidHeader(data [] byte) bool. Controls the dictionary size used by the LZMA and LZMA2 compressors, in kilobytes. The decompressor already supports dictionaries up to one byte less than 4 GiB, which is the maximum for the LZMA1 and LZMA2 stream formats. 02: -mx1 -m0=lzma2:d27:fb273 (equivalent to Fastest level, LZMA2 method, dictionary size 128 MB, word size 273). (2^12 - 2^31); If I had used a dictionary with size of other values( Of cause it will be bigger then 4K and less then 2G, but not power of 2. While standard 7zip or WinRar compression gave me a file of about 400/500Mb, these Mar 20, 2024 · -uncompressed size of the file, which is needed by the boot code. lzma2 is the method of compression employed by the 7-Zip LZMA2 compressor. High compression ratio Variable dictionary size (up to 4 GB) Compressing speed: about 2-8 MB/s on 4 GHz CPU (2 cpu threads version). 7-Zip uses different rules for links. 20: New small SFX module for installers. Decompressing speed: about 30-100 MB/s on 4 GHz CPU (1 cpu thread). Apr 12, 2017 · [Setup] SolidCompression=yes Compression=lzma2/ultra64 LZMAUseSeparateProcess=yes LZMADictionarySize=1048576 LZMANumFastBytes=273 Use defaults for other compression-related directives. 15 beta (2010-06-20) using LZMA2. If there is an explicit size it must not exceed 256 GiB. A single file compresses to 33758 KB, two identical files, to 33775 KB. exe given by 7z standard SDK (with -d23 argument, 2^23 dict size) and then. By running following command. To do explicit memory management (set dictionary size, buffer size, etc. Solid Block size: Solid Sep 19, 2015 · Solid Block size: 4 GB; Number of CPU threads: 4; Encryption parameters: Encryption method: AES-256 ; Encrypt file names: True ; The password for the encryption is chosen such that it won't be found in any dictionary and is rather an almost random string (composed of 15-20 upper and lower case letters, numbers, and symbols). 7-Zip writes an additional field for the filename in UTF-8 encoding in ZIP archives. I am looking here: The LZMA2 header consists of a byte indicating the dictionary size: 40 indicates a 4 GB − 1 dictionary size; Even values less than 40 indicate a 2 v/2 + 12 bytes dictionary size; Odd values less than 40 indicate a 3×2 (v − 1)/2 + 11 bytes dictionary size; Values higher than 40 are invalid; LZMA2 data consists of packets starting with a DictSize is the LZMA2 dictionary size. With the SolidCompression, it helps, if you order files in the [Files] section by an extension and similarity. May 26, 2023 · Good day! It will be good (for very bit data sizes) to add support for 4096 MB dictionary size for lzma-fast Nov 21, 2021 · Maximum dictionary size for LZMA/LZMA2 compression operations was increased to 4 Gigabytes. 2. The decoder needs to have the dictionary in RAM, thus big dictionaries cannot be used for files that are intended to be decoded by the kernel. Usually, higher dictionary size gives more compression ratio, but compressing can be slower, and it can require more memory. Variable dictionary size (up to 4 GB) Compressing speed: about 2-8 MB/s on 4 GHz CPU (2 cpu threads version). Read 7-Zip License information. Mar 5, 2014 · Since no explicit restrictions are imposed on solid block size, the s=on switch means arbitrary large solid block, i. All data structures are allocated at initialization, so xz_dec_run() cannot return XZ_MEM_ERROR. 1 is a LZMA2 compression algorithm, 20% to 100% faster than normal LZMA2 at levels 5 and above, but with a slightly lower compression ratio. Threads I set to (amount of threads in CPU -1), so in my case that's 15 (8 cores 16 threads). 5 GiB (1536 MiB). PPMd. It doesn't store file name. 7z. Sep 2, 2021 · The lzma header should look something like this 1. PDF for C++ - API Reference,sendmessagesresult - Aspose. This is why it is good to avoid using the presets -7 -9 when there's no real need for them. In multi-threaded mode, the sizes of Largest dictionary size supported by this implementation. 0. Dictionary size - largest value allowed for RAM size at your computer. You can use 7-Zip on any computer, including a computer in a commercial organization. Oct 20, 2020 · The Fast LZMA2 library documentation combined with the source for the 7-zip interface should cover everything. Some parts of the code are under the BSD 3-clause License. Solid Block size: 1GB. + - $(call if_changed,xzkern_with_size) is like xzkern above but this + also appends a four-byte trailer containing the uncompressed size The LZMA2 header consists of a byte indicating the dictionary size: 40 indicates a 4 GB − 1 dictionary size; Even values less than 40 indicate a 2 v/2 + 12 bytes dictionary size; Odd values less than 40 indicate a 3×2 (v − 1)/2 + 11 bytes dictionary size; Values higher than 40 are invalid; LZMA2 data consists of packets starting with a Jan 10, 2013 · : Multi-call mode with preallocated LZMA2 dictionary buffer. Mar 13, 2021 · Dictionary size and match finder (mf) together determine the memory usage of the LZMA1 or LZMA2 encoder. Using size less than the LZMA2 dictionary size is waste of RAM because then the LZMA2 dictionary buffer will never get fully used. php, . john lee - 2017-01-17. The maximum dictionary size for LZMA/LZMA2 compressing was increased to 4 GB (3840 MiB). Small memory requirements for decompressing (depend from dictionary size) Small code size for decompressing: about 5 KB Jun 20, 2023 · 18. error on load file : xz: LZMA2 dictionary size exceeds max file: google-chrome-beta_107. So you can get different compression ratio for different number It provides better multithreading support than LZMA. The same (or big- ger) dictionary size is required for decompressing that was used when compressing, thus the memory usage of the decoder is determined by the dictionary size used when compressing. 04: LZMA2 and XZ support. Levels: 1. Jan 6, 2016 · 12. If you have the patience, going for ultra compression pays off. The largest caveat is that the match-finder is a block algorithm, and to achieve about the same ratio as 7-Zip requires double the dictionary size, which raises the decompression memory usage. 2) . When using tar (to create solid archive) and xz -6 (to define compression dictionary to be bigger than one file - Update - this was not enough! Jan 18, 2020 · As documented in the Custom compressor filter chains section, you can simply supply manually the dictionary size to xz with for example --lzma2=dict=150MiB (we have insight information telling 150MiB is enough, else in doubt the file size would have to be used). Description: Controls the dictionary size used by the LZMA and LZMA2 compressors, in kilobytes. Review the memory requirements listed in the Compression topic before using. Compressed Size: 12,676,886 bytes. Also there is unRAR license restriction for some parts of the code. If you use LZMA2 with more than 2 threads, 7-zip splits data to chunks and compresses these chunks independently (2 threads per each chunk). Oct 17, 2012 · 1) . 3. Aug 17, 2020 · !sevenZip! A -T7Z -M0=LZMA2 -MX9 !archivePath! !sourcePath! Ultimately I'd like to use the following settings from the GUI: Archive Format: 7-zip becomes -t7z. 128,256,273, to find the best one. "16" is that byte, meaning a dictionary size of 0x80_0000 (see section “5. The length of the data argument must be HeaderLen. ex a –mx9 –m0=LZMA2:D1024M –ms=1g –mmt=2 DESTI. To use these methods, go to the "Options" menu in WinRAR and select "Settings. I have updated the Fast LZMA2 library to fix this, but FL2_DICTSIZE_MAX still limits it to 1024 Mb. But compression ratio can be worse in some cases. CPU threads: 2. fully solid. Nov 24, 2010 · It is enough that + * the output buffer is big enough to hold the actual uncompressed data; it + * can be smaller than the dictionary size stored in the stream headers. Added Igor Pavlov's assembler-optimized decoder. level - ultra. By default, word size will be 64MB if you’re using the LZMA or LZMA2 compression method, and that’s good enough. jpeg, . 65536 if the LZMA compression level is set to ultra64. For best compression ratio with LZMA2 use 1 or 2 CPU threads. 1. html, . WordSize: usually the bigger, the better (and slower) for well-compressible data (such as documents). Single file can be compressed from 30 MB to 13-15 MB (with xz -1, gz -1, bzip2 -1 ), but when compressing two or more files I want to have archive with size 13-15MB + N*0. 005%, compared to 1. 7z -m9=LZMA2 -aoa. Note: LZMA2 uses: 1 thread for each chunk in x1 and x3 modes; and 2 threads for each chunk in x5, x7 and x9 modes. Like binary programs and stuff. Using size less than the LZMA2 dictionary size is waste of RAM be- cause then the LZMA2 dictionary buffer will never get fully used. Mar 31, 2011 · 2. lc: Number of literal context bits. -Other things should be compressed with $(call if_needed,xzmisc)-which will use no BCJ filter and 1 MiB LZMA2 dictionary. Fast LZMA2 v1. 35% with original LZMA), and optionally can compress multiple parts of large files in parallel, greatly increasing compression speed but with a possible reduction in Dec 15, 2021 · LZMA and LZMA2 algorithms are limited to 4096 MiB dictionary. Word size - Same thing as dictionary size 7-Zip Command Line Reference Wizard ☰. 18. ) the lzma. -ms+ is just a short-hand for -ms=on . Settings used were word size 273, dictionary size 64MB and I used 2 threads for compression. XZ is an open-source data compression method that makes use of the LZMA2 algorithm to produce a higher compression ratio. nmfurnxosghmcqoqmpag
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