Solana与链上内容存储：高吞吐量如何支撑视频NFT铸造

// SPDX-License-Identifier: MIT
// Solidity示例：视频NFT元数据合约（跨链兼容EVM的Solana程序参考）
pragma solidity ^0.8.20;

contract VideoNFT {
    struct VideoMetadata {
        string title;
        string director;
        uint256 duration; // 帧数
        bytes32 frameHash; // 首帧哈希
        bytes32 integrityRoot; // Merkle根
        string storageUri; // Arweave/IPFS URI
        uint256 mintTimestamp;
    }

    mapping(uint256 => VideoMetadata) public videos;
    uint256 public tokenCounter;

    event VideoMinted(
        uint256 indexed tokenId,
        bytes32 indexed frameHash,
        address indexed minter,
        uint256 timestamp
    );

    function mintVideoNFT(
        string memory _title,
        string memory _director,
        uint256 _duration,
        bytes32 _frameHash,
        bytes32 _integrityRoot,
        string memory _storageUri
    ) external returns (uint256) {
        tokenCounter++;
        uint256 newTokenId = tokenCounter;

        videos[newTokenId] = VideoMetadata({
            title: _title,
            director: _director,
            duration: _duration,
            frameHash: _frameHash,
            integrityRoot: _integrityRoot,
            storageUri: _storageUri,
            mintTimestamp: block.timestamp
        });

        emit VideoMinted(newTokenId, _frameHash, msg.sender, block.timestamp);
        return newTokenId;
    }

    function verifyFrameIntegrity(
        uint256 _tokenId,
        bytes32[] calldata _proof,
        bytes32 _leaf
    ) external view returns (bool) {
        bytes32 computedRoot = _leaf;
        for (uint256 i = 0; i < _proof.length; i++) {
            computedRoot = computedRoot < _proof[i]
                ? keccak256(abi.encodePacked(computedRoot, _proof[i]))
                : keccak256(abi.encodePacked(_proof[i], computedRoot));
        }
        return computedRoot == videos[_tokenId].integrityRoot;
    }
}

# Python示例：使用Solana客户端批量铸造视频NFT
from solana.rpc.api import Client
from solders.pubkey import Pubkey
from solders.system_program import transfer, TransferParams
from solders.keypair import Keypair
from spl.token.constants import TOKEN_PROGRAM_ID
from spl.token.instructions import (
    create_associated_token_account,
    mint_to,
    get_associated_token_address,
)
import json
import hashlib
import os

# 连接到Solana主网（或Devnet）
client = Client("https://api.mainnet-beta.solana.com")

# 加载创作者钱包
creator = Keypair.from_bytes(bytes.fromhex("YOUR_PRIVATE_KEY_HEX"))

class VideoNFTCaster:
    def __init__(self, client: Client, authority: Keypair):
        self.client = client
        self.authority = authority
        self.mint_authority = authority.public_key

    def compute_frame_merkle_root(self, video_path: str, frame_interval: int = 100) -> bytes:
        """计算视频帧的Merkle根，用于链上完整性验证"""
        import subprocess
        # 使用ffprobe提取关键帧信息
        result = subprocess.run([
            "ffprobe", "-v", "quiet",
            "-print_format", "json",
            "-show_frames",
            "-select_streams", "v:0",
            video_path
        ], capture_output=True, text=True)
        frames = json.loads(result.stdout).get("frames", [])

        # 每隔frame_interval帧提取一个哈希
        leaves = []
        for i, frame in enumerate(frames):
            if i % frame_interval == 0:
                frame_data = json.dumps({
                    "pts": frame.get("pkt_pts"),
                    "size": frame.get("pkt_size"),
                    "pict_type": frame.get("pict_type")
                }, sort_keys=True)
                leaf_hash = hashlib.sha256(frame_data.encode()).digest()
                leaves.append(leaf_hash)

        # 构建Merkle树
        if not leaves:
            return bytes(32)

        while len(leaves) > 1:
            if len(leaves) % 2 != 0:
                leaves.append(leaves[-1])
            new_level = []
            for i in range(0, len(leaves), 2):
                combined = leaves[i] + leaves[i + 1]
                new_level.append(hashlib.sha256(combined).digest())
            leaves = new_level

        return leaves[0]

    def prepare_metadata(self, title: str, director: str, video_path: str) -> dict:
        """准备链上元数据"""
        merkle_root = self.compute_frame_merkle_root(video_path).hex()

        metadata = {
            "name": title,
            "symbol": "VIDEO",
            "description": f"Video NFT by {director}",
            "seller_fee_basis_points": 500,  # 5%版税
            "image": "ar://VIDEO_POSTER_ARWEAVE_HASH",
            "animation_url": "ar://FULL_VIDEO_ARWEAVE_HASH",
            "attributes": [
                {"trait_type": "Director", "value": director},
                {"trait_type": "Frame Merkle Root", "value": merkle_root},
                {"trait_type": "Codec", "value": "H.265"},
                {"trait_type": "Resolution", "value": "3840x2160"},
            ],
            "properties": {
                "creators": [
                    {"address": str(self.authority.public_key), "share": 100}
                ],
                "files": [
                    {"uri": "ar://FULL_VIDEO_ARWEAVE_HASH",
                     "type": "video/mp4"}
                ]
            }
        }
        return metadata

    def batch_mint(self, metadata_list: list[dict]) -> list[str]:
        """批量铸造NFT"""
        mint_addresses = []
        for metadata in metadata_list:
            metadata_json = json.dumps(metadata, ensure_ascii=False)
            metadata_uri = self.upload_to_arweave(metadata_json)

            # 创建Mint账户
            mint_keypair = Keypair()
            # 此处省略actual token mint指令构建
            # 实际使用需要spl_token指令集

            mint_addresses.append(str(mint_keypair.public_key))
            print(f"Minted: {metadata['name']} -> {mint_keypair.public_key}")

        return mint_addresses

    def upload_to_arweave(self, data: str) -> str:
        """上传元数据到Arweave（示例，实际需集成arweave-py）"""
        # 模拟上传
        return "ar://MOCK_TX_ID"

// JavaScript示例：基于Solana Web3.js的视频NFT播放器验证
const { Connection, PublicKey } = require('@solana/web3.js');
const { getAccount } = require('@solana/spl-token');
const { create } = require('ipfs-http-client');
const crypto = require('crypto');

// Solana主网连接
const connection = new Connection('https://api.mainnet-beta.solana.com');

// IPFS客户端（用于链下视频流）
const ipfs = create({ url: 'https://ipfs.infura.io:5001' });

class SolanaVideoPlayer {
  constructor(mintAddress) {
    this.mintPubkey = new PublicKey(mintAddress);
    this.segmentCache = new Map();
    this.verifiedSegments = 0;
    this.totalSegments = 0;
  }

  async loadVideoMetadata() {
    // 获取Metaplex元数据账户
    const [metadataPDA] = await PublicKey.findProgramAddress(
      [
        Buffer.from('metadata'),
        new PublicKey('metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s').toBuffer(),
        this.mintPubkey.toBuffer(),
      ],
      new PublicKey('metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s')
    );

    const metadataAccount = await connection.getAccountInfo(metadataPDA);
    if (!metadataAccount) {
      throw new Error('Metadata not found');
    }

    // 解析元数据（简化处理）
    const metadata = this.parseMetadata(metadataAccount.data);
    return metadata;
  }

  parseMetadata(data) {
    // 实际需使用@metaplex-foundation/mpl-token-metadata
    // 此处为简化示例
    return {
      name: data.toString('utf8', 68, 100).replace(/\0/g, ''),
      uri: data.toString('utf8', 132, 300).replace(/\0/g, ''),
    };
  }

  async verifySegment(segmentData, segmentHash) {
    const computedHash = crypto
      .createHash('sha256')
      .update(segmentData)
      .digest('hex');

    return computedHash === segmentHash;
  }

  async fetchAndVerifySegment(ipfsCid, expectedHash, retries = 3) {
    for (let attempt = 0; attempt < retries; attempt++) {
      try {
        // 从IPFS通过CDN网关获取片段
        const chunks = [];
        for await (const chunk of ipfs.cat(ipfsCid)) {
          chunks.push(chunk);
        }
        const segmentData = Buffer.concat(chunks);

        // 链上哈希验证
        const isValid = await this.verifySegment(segmentData, expectedHash);

        if (isValid) {
          this.verifiedSegments++;
          return segmentData;
        }

        console.warn(`Segment verification failed, retry ${attempt + 1}`);
      } catch (err) {
        console.error(`Fetch error: ${err.message}`);
      }
    }
    throw new Error('Segment verification failed after all retries');
  }

  async playStream(segmentCids, segmentHashes) {
    this.totalSegments = segmentCids.length;
    console.log(`Starting playback: ${this.totalSegments} segments`);

    for (let i = 0; i < segmentCids.length; i++) {
      const segmentData = await this.fetchAndVerifySegment(
        segmentCids[i],
        segmentHashes[i]
      );
      // 将解码后的片段传递给MediaSource
      this.appendToBuffer(segmentData, i);
    }

    console.log(`Playback complete: ${this.verifiedSegments}/${this.totalSegments} verified`);
  }

  appendToBuffer(segmentData, index) {
    // MediaSource API集成
    // 实际实现需使用WebCodecs或MediaSource Extensions
    console.log(`Appending segment ${index}: ${segmentData.length} bytes`);
  }
}

// 使用示例
async function main() {
  const player = new SolanaVideoPlayer('VIDEO_NFT_MINT_ADDRESS');
  const metadata = await player.loadVideoMetadata();
  console.log(`Playing: ${metadata.name}`);

  const segmentCids = ['QmHash1', 'QmHash2', 'QmHash3'];
  const segmentHashes = [
    'abc123...',
    'def456...',
    'ghi789...',
  ];

  await player.playStream(segmentCids, segmentHashes);
}

main().catch(console.error);