256 lines
9.6 KiB
Swift
256 lines
9.6 KiB
Swift
import Flutter
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import UIKit
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import AVFoundation
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public class VideoDecodePlugin: NSObject, FlutterPlugin, FlutterTexture {
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private var channel: FlutterMethodChannel?
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private var registrar: FlutterPluginRegistrar?
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private var decoder: VideoDecoder?
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private var textureId: Int64?
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private var textureRegistry: FlutterTextureRegistry?
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private var latestPixelBuffer: CVPixelBuffer?
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private let textureQueue = DispatchQueue(label: "video_decode_plugin.texture.queue")
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private var cachedSps: Data?
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private var cachedPps: Data?
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private var hasNotifiedFlutter = false
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public static func register(with registrar: FlutterPluginRegistrar) {
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let channel = FlutterMethodChannel(name: "video_decode_plugin", binaryMessenger: registrar.messenger())
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let instance = VideoDecodePlugin()
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instance.channel = channel
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instance.registrar = registrar
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instance.textureRegistry = registrar.textures()
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registrar.addMethodCallDelegate(instance, channel: channel)
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}
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public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
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switch call.method {
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case "initDecoder":
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handleInitDecoder(call: call, result: result)
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case "decodeFrame":
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handleDecodeFrame(call: call, result: result)
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case "releaseDecoder":
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handleReleaseDecoder(call: call, result: result)
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default:
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result(FlutterMethodNotImplemented)
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}
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}
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/// 初始化解码器
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private func handleInitDecoder(call: FlutterMethodCall, result: @escaping FlutterResult) {
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guard let args = call.arguments as? [String: Any],
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let width = args["width"] as? Int,
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let height = args["height"] as? Int,
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let codecType = args["codecType"] as? String else {
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print("[VideoDecodePlugin][错误] 参数解析失败：\(String(describing: call.arguments))")
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result(FlutterError(code: "INVALID_ARGS", message: "参数错误", details: nil))
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return
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}
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// 释放旧解码器和纹理
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decoder?.release()
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decoder = nil
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if let tid = textureId {
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textureRegistry?.unregisterTexture(tid)
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textureId = nil
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}
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// 注册Flutter纹理
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guard let registry = textureRegistry else {
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print("[VideoDecodePlugin][错误] 无法获取纹理注册表")
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result(FlutterError(code: "NO_TEXTURE_REGISTRY", message: "无法获取纹理注册表", details: nil))
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return
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}
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let textureId = registry.register(self)
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self.textureId = textureId
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// 创建解码器
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let decoder = VideoDecoder(width: width, height: height, codecType: codecType)
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self.decoder = decoder
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decoder.onFrameDecoded = { [weak self] pixelBuffer, _ in
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guard let self = self else { return }
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self.textureQueue.async {
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self.latestPixelBuffer = pixelBuffer
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self.textureRegistry?.textureFrameAvailable(self.textureId ?? 0)
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if !self.hasNotifiedFlutter {
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self.hasNotifiedFlutter = true
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DispatchQueue.main.async {
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self.channel?.invokeMethod("onFrameRendered", arguments: ["textureId": self.textureId ?? 0])
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}
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}
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}
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}
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print("[VideoDecodePlugin] 解码器初始化成功，textureId=\(textureId)")
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result(textureId)
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}
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/// 去除NALU起始码的工具方法
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private func stripStartCode(_ data: Data) -> Data {
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var stripped: Data = data
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if data.count > 4 && data[0] == 0x00 && data[1] == 0x00 && data[2] == 0x00 && data[3] == 0x01 {
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stripped = data.subdata(in: 4..<data.count)
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} else if data.count > 3 && data[0] == 0x00 && data[1] == 0x00 && data[2] == 0x01 {
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stripped = data.subdata(in: 3..<data.count)
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}
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return stripped
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}
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// 修改：更合理的side_data检测工具
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private func checkNaluForSideData(_ nalu: Data, naluType: UInt8) -> Bool {
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let maxSize = naluType == 5 ? 150_000 : 30_000 // I帧最大150KB，P帧最大30KB
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if nalu.count > maxSize {
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print("[VideoDecodePlugin][警告] NALU长度异常，可能包含side_data，type=\(naluType)，len=\(nalu.count)")
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return true
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}
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return false
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}
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// 简化：提取第一个合法NALU工具
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private func extractFirstValidNalu(_ nalu: Data) -> Data {
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// 查找第一个起始码（支持3字节和4字节格式）
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var start = -1
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var startCodeLength = 0
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// 检查4字节起始码
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if nalu.count >= 4 && nalu[0] == 0x00 && nalu[1] == 0x00 && nalu[2] == 0x00 && nalu[3] == 0x01 {
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start = 0
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startCodeLength = 4
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}
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// 检查3字节起始码
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else if nalu.count >= 3 && nalu[0] == 0x00 && nalu[1] == 0x00 && nalu[2] == 0x01 {
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start = 0
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startCodeLength = 3
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}
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// 在数据中间查找起始码
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else {
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for i in 0..<(nalu.count - 4) {
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if nalu[i] == 0x00 && nalu[i + 1] == 0x00 {
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if nalu[i + 2] == 0x00 && nalu[i + 3] == 0x01 {
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start = i
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startCodeLength = 4
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break
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} else if nalu[i + 2] == 0x01 {
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start = i
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startCodeLength = 3
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break
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}
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}
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}
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}
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if start == -1 {
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print("[VideoDecodePlugin][警告] NALU无AnnexB起始码，丢弃该帧")
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return Data()
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}
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let searchRange = (start + startCodeLength)..<nalu.count
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var end = nalu.count
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// 查找下一个起始码（同时支持3字节和4字节格式）
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for i in searchRange.lowerBound..<(nalu.count - 3) {
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if nalu[i] == 0x00 && nalu[i + 1] == 0x00 {
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if i + 3 < nalu.count && nalu[i + 2] == 0x00 && nalu[i + 3] == 0x01 {
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end = i
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break
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} else if nalu[i + 2] == 0x01 {
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end = i
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break
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}
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}
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}
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let extractedNalu = nalu[start..<end]
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// 验证提取的NALU
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if extractedNalu.count >= startCodeLength + 1 {
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let naluType = extractedNalu[startCodeLength] & 0x1F
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if checkNaluForSideData(extractedNalu, naluType: naluType) {
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return Data()
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}
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}
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return extractedNalu
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}
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/// 解码视频帧
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private func handleDecodeFrame(call: FlutterMethodCall, result: @escaping FlutterResult) {
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guard let args = call.arguments as? [String: Any],
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let frameData = args["frameData"] as? FlutterStandardTypedData,
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let frameType = args["frameType"] as? Int,
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let timestamp = args["timestamp"] as? Int,
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let frameSeq = args["frameSeq"] as? Int else {
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result(FlutterError(code: "INVALID_ARGS", message: "参数错误", details: nil))
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return
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}
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let refIFrameSeq = args["refIFrameSeq"] as? Int
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let data = frameData.data
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// 解析NALU类型
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let naluType: UInt8 = {
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if data.count > 4 && data[0] == 0x00 && data[1] == 0x00 && data[2] == 0x00 && data[3] == 0x01 {
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return data[4] & 0x1F
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} else if data.count > 3 && data[0] == 0x00 && data[1] == 0x00 && data[2] == 0x01 {
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return data[3] & 0x1F
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}
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return 0
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}()
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// 缓存SPS/PPS（去除起始码）
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if naluType == 7 { // SPS
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cachedSps = stripStartCode(data)
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result(true)
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return
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} else if naluType == 8 { // PPS
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cachedPps = stripStartCode(data)
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result(true)
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return
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} else if naluType == 5 { // IDR/I帧
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// 提取第一个合法NALU
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let firstNalu = extractFirstValidNalu(data)
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if firstNalu.isEmpty {
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result(false)
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return
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}
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decoder?.decodeFrame(frameData: firstNalu, frameType: frameType, timestamp: Int64(timestamp), frameSeq: frameSeq, refIFrameSeq: refIFrameSeq, sps: cachedSps, pps: cachedPps)
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} else {
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// 提取第一个合法NALU
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let firstNalu = extractFirstValidNalu(data)
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if firstNalu.isEmpty {
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result(false)
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return
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}
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decoder?.decodeFrame(frameData: firstNalu, frameType: frameType, timestamp: Int64(timestamp), frameSeq: frameSeq, refIFrameSeq: refIFrameSeq)
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}
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result(true)
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}
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/// 释放解码器资源
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private func handleReleaseDecoder(call: FlutterMethodCall, result: @escaping FlutterResult) {
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decoder?.release()
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decoder = nil
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if let tid = textureId {
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textureRegistry?.unregisterTexture(tid)
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textureId = nil
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}
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latestPixelBuffer = nil
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hasNotifiedFlutter = false
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print("[VideoDecodePlugin] 解码器和纹理已释放")
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result(true)
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}
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// MARK: - FlutterTexture协议实现
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public func copyPixelBuffer() -> Unmanaged<CVPixelBuffer>? {
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var pixelBuffer: CVPixelBuffer?
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textureQueue.sync {
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pixelBuffer = self.latestPixelBuffer
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}
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if let pb = pixelBuffer {
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return Unmanaged.passRetained(pb)
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}
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return nil
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}
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}
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