# bvid说明 2020-03-23 B站推出了全新的稿件视频id`bvid`来接替之前的`avid`，其意义与之相同详见： 1. [【升级公告】AV号全面升级至BV号（专栏）](https://www.bilibili.com/read/cv5167957) 2. [【升级公告】AV号全面升级至BV号](https://www.bilibili.com/blackboard/activity-BV-PC.html) ## 概述 ### 格式 “bvid”恒为长度为 12 的字符串，前两个固定为“BV1”，后 9 个为 base58 计算结果（不包含数字 `0` 和大写字母 `I`、 `O` 以及小写字母 `l`） ### 实质 “bvid"为“avid”的base58编码，可通过算法进行相互转化 ### avid发号方式的变化从 2009-09-09 09:09:09 [av2](https://www.bilibili.com/video/av2) 的发布到 2020-03-28 19:45:02 [av99999999](https://www.bilibili.com/video/av99999999) 的发布B站结束了以投稿时间为顺序的avid发放，改为随机发放avid ~~暗示B站东方要完？泪目~~ ## 算法概述 ~~算法以及程序主要参考[知乎@mcfx的回答](https://www.zhihu.com/question/381784377/answer/1099438784)~~ ~~实际上该算法并不完整,新的算法参考自[【揭秘】av号转bv号的过程](https://www.bilibili.com/video/BV1N741127Tj)~~ 实际上上面的算法依然不完整，新的算法参考自 [SocialSisterYi#740](https://github.com/SocialSisterYi/bilibili-API-collect/issues/740)~~来自 B 站某个 JS 文件？~~ ### av->bv算法 **说明** 1. 目前的 BV 格式为 BV1XXXXXXXXX，以 BV1 开头，后面包含 9 位有效数据。 2. AV 最大值为 2⁵¹。 **算法** - 定义一个包含初始值为 `['B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0']` 的长度为 12 的数组`bytes`，用于存储转换后的字符。 - 定义变量 `bv_idx` 并初始化为数组 `bytes` 的最后一个索引。 - 将输入的 `aid` 与 avid 最大值（2⁵¹）进行按位或运算，其结果与常量 `XOR_CODE`（23442827791579）进行异或运算，得到变量 `tmp`。 - 当 `tmp` 大于0时，循环执行以下操作直到小于0： - 将 `tmp` 除以 58（码表的长度）的余数作为索引，从 `FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf` 码表中取出对应的字符，并将其赋值给 `bytes[bv_idx]`。 - 将 `tmp` 与 58 求模赋值给 `tmp`。 - 将 `bv_idx` 减1。 - 将 `bytes` 数组中索引为 3 和 9 的元素进行交换。 - 将 `bytes` 数组中索引为 4 和 7 的元素进行交换。 - 将 `bytes` 数组转换为字符串，并返回结果。 ### bv->av算法是 #av->bv算法的逆向 - 将 `bvid` 中索引为 3 和 9 的字符进行交换。 - 将 `bvid` 中索引为 4 和 7 的字符进行交换。 - 删除 `bvid` 前3个字符（固定为 BV1）。 - 定义变量 `tmp` 并初始化为 0。 - 遍历 `bvid` 的每个字符，执行以下操作： - 获取当前字符在 `FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf` 码表中的索引，并将其赋值给变量 `idx`。 - 将 `tmp` 乘以常量 58，并加上 `idx`，最后赋值给 `tmp`。 - 将 `tmp` 与常量 2⁵¹ - 1 进行按位与运算，其结果与常量 `XOR_CODE`（23442827791579）进行异或运算，得到最终结果。 ## 编程实现 ### JavaScript/TypeScript ```javascript const XOR_CODE = 23442827791579n; const MASK_CODE = 2251799813685247n; const MAX_AID = 1n << 51n; const BASE = 58n; const data = 'FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf'; function av2bv(aid) { const bytes = ['B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0']; let bvIndex = bytes.length - 1; let tmp = (MAX_AID | BigInt(aid)) ^ XOR_CODE; while (tmp > 0) { bytes[bvIndex] = data[Number(tmp % BigInt(BASE))]; tmp = tmp / BASE; bvIndex -= 1; } [bytes[3], bytes[9]] = [bytes[9], bytes[3]]; [bytes[4], bytes[7]] = [bytes[7], bytes[4]]; return bytes.join(''); } function bv2av(bvid) { const bvidArr = Array.from(bvid); [bvidArr[3], bvidArr[9]] = [bvidArr[9], bvidArr[3]]; [bvidArr[4], bvidArr[7]] = [bvidArr[7], bvidArr[4]]; bvidArr.splice(0, 3); const tmp = bvidArr.reduce((pre, bvidChar) => pre * BASE + BigInt(data.indexOf(bvidChar)), 0n); return Number((tmp & MASK_CODE) ^ XOR_CODE); } console.log(av2bv(111298867365120)); console.log(bv2av('BV1L9Uoa9EUx')); ``` ```typescript const XOR_CODE = 23442827791579n; const MASK_CODE = 2251799813685247n; const MAX_AID = 1n << 51n; const BASE = 58n; const data = 'FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf'; function av2bv(aid: number) { const bytes = ['B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0']; let bvIndex = bytes.length - 1; let tmp = (MAX_AID | BigInt(aid)) ^ XOR_CODE; while (tmp > 0) { bytes[bvIndex] = data[Number(tmp % BigInt(BASE))]; tmp = tmp / BASE; bvIndex -= 1; } [bytes[3], bytes[9]] = [bytes[9], bytes[3]]; [bytes[4], bytes[7]] = [bytes[7], bytes[4]]; return bytes.join('') as `BV1${string}`; } function bv2av(bvid: `BV1${string}`) { const bvidArr = Array.from(bvid); [bvidArr[3], bvidArr[9]] = [bvidArr[9], bvidArr[3]]; [bvidArr[4], bvidArr[7]] = [bvidArr[7], bvidArr[4]]; bvidArr.splice(0, 3); const tmp = bvidArr.reduce((pre, bvidChar) => pre * BASE + BigInt(data.indexOf(bvidChar)), 0n); return Number((tmp & MASK_CODE) ^ XOR_CODE); } console.log(av2bv(111298867365120)); console.log(bv2av('BV1L9Uoa9EUx')); ``` ### Python 来自：[SocialSisterYi#847 (comment)](https://github.com/SocialSisterYi/bilibili-API-collect/issues/847#issuecomment-1807020675) ```python XOR_CODE = 23442827791579 MASK_CODE = 2251799813685247 MAX_AID = 1 << 51 data = [b'F', b'c', b'w', b'A', b'P', b'N', b'K', b'T', b'M', b'u', b'g', b'3', b'G', b'V', b'5', b'L', b'j', b'7', b'E', b'J', b'n', b'H', b'p', b'W', b's', b'x', b'4', b't', b'b', b'8', b'h', b'a', b'Y', b'e', b'v', b'i', b'q', b'B', b'z', b'6', b'r', b'k', b'C', b'y', b'1', b'2', b'm', b'U', b'S', b'D', b'Q', b'X', b'9', b'R', b'd', b'o', b'Z', b'f'] BASE = 58 BV_LEN = 12 PREFIX = "BV1" def av2bv(aid: int) -> str: bytes = [b'B', b'V', b'1', b'0', b'0', b'0', b'0', b'0', b'0', b'0', b'0', b'0'] bv_idx = BV_LEN - 1 tmp = (MAX_AID | aid) ^ XOR_CODE while int(tmp) != 0: bytes[bv_idx] = data[int(tmp % BASE)] tmp /= BASE bv_idx -= 1 bytes[3], bytes[9] = bytes[9], bytes[3] bytes[4], bytes[7] = bytes[7], bytes[4] return "".join([i.decode() for i in bytes]) def bv2av(bvid: str) -> int: bvid = list(bvid) bvid[3], bvid[9] = bvid[9], bvid[3] bvid[4], bvid[7] = bvid[7], bvid[4] bvid = bvid[3:] tmp = 0 for i in bvid: idx = data.index(i.encode()) tmp = tmp * BASE + idx return (tmp & MASK_CODE) ^ XOR_CODE print(av2bv(111298867365120)) print(bv2av("BV1L9Uoa9EUx")) ``` ### Rust 参考 ### Swift ```swift fileprivate let XOR_CODE: UInt64 = 23442827791579 fileprivate let MASK_CODE: UInt64 = 2251799813685247 fileprivate let MAX_AID: UInt64 = 1 << 51 fileprivate let data: [UInt8] = [70, 99, 119, 65, 80, 78, 75, 84, 77, 117, 103, 51, 71, 86, 53, 76, 106, 55, 69, 74, 110, 72, 112, 87, 115, 120, 52, 116, 98, 56, 104, 97, 89, 101, 118, 105, 113, 66, 122, 54, 114, 107, 67, 121, 49, 50, 109, 85, 83, 68, 81, 88, 57, 82, 100, 111, 90, 102] fileprivate let BASE: UInt64 = 58 fileprivate let BV_LEN: Int = 12 fileprivate let PREFIX: String = "BV1" func av2bv(avid: UInt64) -> String { var bytes: [UInt8] = [66, 86, 49, 48, 48, 48, 48, 48, 48, 48, 48, 48] var bvIdx = BV_LEN - 1 var tmp = (MAX_AID | avid) ^ XOR_CODE while tmp != 0 { bytes[bvIdx] = data[Int(tmp % BASE)] tmp /= BASE bvIdx -= 1 } bytes.swapAt(3, 9) bytes.swapAt(4, 7) return String(decoding: bytes, as: UTF8.self) } func bv2av(bvid: String) -> UInt64 { let fixedBvid: String if bvid.hasPrefix("BV") { fixedBvid = bvid } else { fixedBvid = "BV" + bvid } var bvidArray = Array(fixedBvid.utf8) bvidArray.swapAt(3, 9) bvidArray.swapAt(4, 7) let trimmedBvid = String(decoding: bvidArray[3...], as: UTF8.self) var tmp: UInt64 = 0 for char in trimmedBvid { if let idx = data.firstIndex(of: char.utf8.first!) { tmp = tmp * BASE + UInt64(idx) } } return (tmp & MASK_CODE) ^ XOR_CODE } print(av2bv(avid: 111298867365120)) print(bv2av(bvid: "BV1L9Uoa9EUx")) ``` ## 老版算法存档算法参考自[【揭秘】av号转bv号的过程](https://www.bilibili.com/video/BV1N741127Tj) ### av->bv算法注：本算法及示例程序仅能编解码`avid < 29460791296`，且暂无法验证`avid >= 29460791296`的正确性再注：本人不清楚新算法能否编解码`avid >= 29460791296` 1. a = (avid ⊕ 177451812) + 100618342136696320 2. 以 i 为循环变量循环 6 次 b[i] = (a / 58 ^ i) % 58 3. 将 b[i] 中各个数字转换为以下码表中的字符码表： > fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF 4. 初始化字符串 b[i]=` ` 5. 按照以下字符顺序编码表编码并填充至 b[i] 字符顺序编码表： > 0 -> 9 > > 1 -> 8 > > 2 -> 1 > > 3 -> 6 > > 4 -> 2 > > 5 -> 4 > > 6 -> 0 > > 7 -> 7 > > 8 -> 3 > > 9 -> 5 ### bv->av算法为以上算法的逆运算 ### 编程实现使用 [Python](#Python) [C](#C) [TypeScript](#TypeScript) [Java](#Java) [Kotlin](#Kotlin) [Golang](#Golang) [Rust](#Rust) 等语言作为示例，欢迎社区提交更多例程注: 新算法只提供了 [Python](#Python) 和 [Rust](#Rust) 版本 #### Python ```python XOR = 177451812 ADD = 100618342136696320 TABLE = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF" MAP = 9, 8, 1, 6, 2, 4, 0, 7, 3, 5 def av2bv(av: int) -> str: av = (av ^ XOR) + ADD bv = [""] * 10 for i in range(10): bv[MAP[i]] = TABLE[(av // 58**i) % 58] return "".join(bv) def bv2av(bv: int) -> int: av = [""] * 10 s = 0 for i in range(10): s += TABLE.find(bv[MAP[i]]) * 58**i av = (s - ADD) ^ XOR return av def main(): while 1: mode = input("1. AV to BV\n2. BV to AV\n3. Exit\n你的选择：") if mode == "1": print(f"BV号是：BV {av2bv(int(input('AV号是：')))}") elif mode == "2": print(f"AV号是：AV {bv2av(input('BV号是：'))}") elif mode == "3": break else: print("输入错误请重新输入") if __name__ == "__main__": main() ``` #### C ```c #include #include #include #include const char table[] = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"; // 码表 char tr[124]; // 反查码表 const unsigned long long XOR = 177451812; // 固定异或值 const unsigned long long ADD = 8728348608; // 固定加法值 const int s[] = {11, 10, 3, 8, 4, 6}; // 位置编码表 // 初始化反查码表 void tr_init() { for (int i = 0; i < 58; i++) tr[table[i]] = i; } unsigned long long bv2av(char bv[]) { unsigned long long r = 0; unsigned long long av; for (int i = 0; i < 6; i++) r += tr[bv[s[i]]] * (unsigned long long)pow(58, i); av = (r - ADD) ^ XOR; return av; } char *av2bv(unsigned long long av) { char *result = (char*)malloc(13); strcpy(result,"BV1 4 1 7 "); av = (av ^ XOR) + ADD; for (int i = 0; i < 6; i++) result[s[i]] = table[(unsigned long long)(av / (unsigned long long)pow(58, i)) % 58]; return result; } int main() { tr_init(); printf("%s\n", av2bv(170001)); printf("%u\n", bv2av("BV17x411w7KC")); return 0; } ``` 输出为： ``` BV17x411w7KC 170001 ``` #### TypeScript 感谢[#417](https://github.com/SocialSisterYi/bilibili-API-collect/issues/417#issuecomment-1186475063)提供 ```typescript export default class BvCode { private TABEL = 'fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF'; // 码表 private TR: Record = {}; // 反查码表 private S = [11, 10, 3, 8, 4, 6]; // 位置编码表 private XOR = 177451812; // 固定异或值 private ADD = 8728348608; // 固定加法值 constructor() { // 初始化反查码表 const len = this.TABEL.length; for (let i = 0; i < len; i++) { this.TR[this.TABEL[i]] = i; } } av2bv(av: number): string { const x_ = (av ^ this.XOR) + this.ADD; const r = ['B', 'V', '1', , , '4', , '1', , '7']; for (let i = 0; i < 6; i++) { r[this.S[i]] = this.TABEL[Math.floor(x_ / 58 ** i) % 58]; } return r.join(''); } bv2av(bv: string): number { let r = 0; for (let i = 0; i < 6; i++) { r += this.TR[bv[this.S[i]]] * 58 ** i; } return (r - this.ADD) ^ this.XOR; } } const bvcode = new BvCode(); console.log(bvcode.av2bv(170001)); console.log(bvcode.bv2av('BV17x411w7KC')); ``` 输出为： ``` BV17x411w7KC 170001 ``` #### Java ```java /** * 算法来自：https://www.zhihu.com/question/381784377/answer/1099438784 */ public class Util { private static final String TABLE = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"; private static final int[] S = new int[]{11, 10, 3, 8, 4, 6}; private static final int XOR = 177451812; private static final long ADD = 8728348608L; private static final Map MAP = new HashMap<>(); static { for (int i = 0; i < 58; i++) { MAP.put(TABLE.charAt(i), i); } } public static String aidToBvid(int aid) { long x = (aid ^ XOR) + ADD; char[] chars = new char[]{'B', 'V', '1', ' ', ' ', '4', ' ', '1', ' ', '7', ' ', ' '}; for (int i = 0; i < 6; i++) { int pow = (int) Math.pow(58, i); long i1 = x / pow; int index = (int) (i1 % 58); chars[S[i]] = TABLE.charAt(index); } return String.valueOf(chars); } public static int bvidToAid(String bvid) { long r = 0; for (int i = 0; i < 6; i++) { r += MAP.get(bvid.charAt(S[i])) * Math.pow(58, i); } return (int) ((r - ADD) ^ XOR); } } ``` #### Kotlin ```kotlin /** * 此程序非完全原创，改编自GH站内某大佬的Java程序，修改了部分代码，且转换为Kotlin * 算法来源同上 */ object VideoUtils { //这里是由知乎大佬不知道用什么方法得出的转换用数字 var ss = intArrayOf(11, 10, 3, 8, 4, 6, 2, 9, 5, 7) var xor: Long = 177451812 //二进制时加减数1 var add = 8728348608L //十进制时加减数2 //变量初始化工作，加载哈希表 private const val table = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF" private val mp = HashMap() private val mp2 = HashMap() //现在，定义av号和bv号互转的方法 //定义一个power乘方方法，这是转换进制必要的 fun power(a: Int, b: Int): Long { var power: Long = 1 for (c in 0 until b) power *= a.toLong() return power } //bv转av方法 fun bv2av(s: String): String { var r: Long = 0 //58进制转换 for (i in 0..57) { val s1 = table.substring(i, i + 1) mp[s1] = i } for (i in 0..5) { r += mp[s.substring(ss[i], ss[i] + 1)]!! * power(58, i) } //转换完成后，需要处理，带上两个随机数 return (r - add xor xor).toString() } //av转bv方法 fun av2bv(st: String): String { try { var s = java.lang.Long.valueOf(st.split("av".toRegex()).dropLastWhile { it.isEmpty() } .toTypedArray()[1]) val sb = StringBuffer("BV1 4 1 7 ") //逆向思路，先将随机数还原 s = (s xor xor) + add //58进制转回 for (i in 0..57) { val s1 = table.substring(i, i + 1) mp2[i] = s1 } for (i in 0..5) { val r = mp2[(s / power(58, i) % 58).toInt()] sb.replace(ss[i], ss[i] + 1, r!!) } return sb.toString() } catch (e: ArrayIndexOutOfBoundsException) { return "" } } } ``` #### Golang ```go package main import "math" const TABLE = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF" var S = [11]uint{11, 10, 3, 8, 4, 6} const XOR = 177451812 const ADD = 8728348608 var TR = map[string]int64{} // 初始化 TR func init() { for i := 0; i < 58; i++ { TR[TABLE[i:i+1]] = int64(i) } } func BV2AV(bv string) int64 { r := int64(0) for i := 0; i < 6; i++ { r += TR[bv[S[i]:S[i]+1]] * int64(math.Pow(58, float64(i))) } return (r - ADD) ^ XOR } func AV2BV(av int64) string { x := (av ^ XOR) + ADD r := []rune("BV1 4 1 7 ") for i := 0; i < 6; i++ { r[S[i]] = rune(TABLE[x/int64(math.Pow(58, float64(i)))%58]) } return string(r) } func main() { println(AV2BV(170001)) println(BV2AV("BV17x411w7KC")) } ``` 输出为： ``` BV17x411w7KC 170001 ``` #### Rust crate: https://github.com/stackinspector/bvid ```rust // Copyright (c) 2023 stackinspector. MIT license. const XORN: u64 = 177451812; const ADDN: u64 = 100618342136696320; const TABLE: [u8; 58] = *b"fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"; const MAP: [usize; 10] = [9, 8, 1, 6, 2, 4, 0, 7, 3, 5]; const REV_TABLE: [u8; 74] = [ 13, 12, 46, 31, 43, 18, 40, 28, 5, 0, 0, 0, 0, 0, 0, 0, 54, 20, 15, 8, 39, 57, 45, 36, 0, 38, 51, 42, 49, 52, 0, 53, 7, 4, 9, 50, 10, 44, 34, 6, 25, 1, 0, 0, 0, 0, 0, 0, 26, 29, 56, 3, 24, 0, 47, 27, 22, 41, 16, 0, 11, 37, 2, 35, 21, 17, 33, 30, 48, 23, 55, 32, 14, 19, ]; const POW58: [u64; 10] = [ 1, 58, 3364, 195112, 11316496, 656356768, 38068692544, 2207984167552, 128063081718016, 7427658739644928, ]; fn av2bv(avid: u64) -> [u8; 10] { let a = (avid ^ XORN) + ADDN; let mut bvid = [0; 10]; for i in 0..10 { bvid[MAP[i]] = TABLE[(a / POW58[i]) as usize % 58]; } bvid } fn bv2av(bvid: [u8; 10]) -> u64 { let mut a = 0; for i in 0..10 { a += REV_TABLE[bvid[MAP[i]] as usize - 49] as u64 * POW58[i]; } (a - ADDN) ^ XORN } // assert_eq!(*b"17x411w7KC", av2bv(170001)); // assert_eq!(170001, bv2av(*b"17x411w7KC")); ```