From 5e13dbf4f62906b592302a564d0cb6620c24d334 Mon Sep 17 00:00:00 2001
From: liyi <m18269109817@163.com>
Date: Tue, 6 May 2025 09:27:46 +0800
Subject: [PATCH] =?UTF-8?q?feat:=E5=A2=9E=E5=8A=A0=E8=87=AA=E9=80=82?=
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---
 README.md                                     | 15 -----
 .../video_decode_plugin/VideoDecoder.kt       | 58 +++++++++++++++++++
 2 files changed, 58 insertions(+), 15 deletions(-)

diff --git a/README.md b/README.md
index 37ee4a4..5ce3cdf 100644
--- a/README.md
+++ b/README.md
@@ -173,21 +173,6 @@ await VideoDecodePlugin.decodeFrame(pFrameData, FrameType.pFrame);
   - 实时视频流解码
   - 基础错误处理
 
-### 现有问题
-- 解码后在flutter渲染实际帧数较低
-  - 方案一：使用原生activity渲染视频数据
-  - 方案二：多个TextureView并行交替渲染
-  - 方案三：待补充
-  - 方案四：待补充
-
-
-### 后续计划
-- [ ] 解码帧数较低
-- [ ] 增加更多错误处理
-- [ ] 完善文档和示例
-- [ ] 添加单元测试
-- [ ] 支持更多编解码格式
-- [ ] 优化内存管理
 
 ## 插件架构与职责
 
diff --git a/android/src/main/kotlin/top/skychip/video_decode_plugin/VideoDecoder.kt b/android/src/main/kotlin/top/skychip/video_decode_plugin/VideoDecoder.kt
index ade4ab9..de73381 100644
--- a/android/src/main/kotlin/top/skychip/video_decode_plugin/VideoDecoder.kt
+++ b/android/src/main/kotlin/top/skychip/video_decode_plugin/VideoDecoder.kt
@@ -79,6 +79,17 @@ class VideoDecoder(
     // 兜底：记录最近一次I帧的frameSeq，P/B帧依赖校验
     @Volatile private var lastIFrameSeq: Int? = null
 
+    // 解码输出帧时间戳队列（用于动态帧率统计和平滑）
+    private val decodeTimestampQueue = ArrayDeque<Long>(20) // 最多保存20帧时间戳
+    private val decodeTimestampLock = ReentrantLock() // 线程安全保护
+
+    // EMA平滑参数
+    @Volatile private var smoothedFps: Double = 18.0 // 平滑后的渲染帧率
+    private val alpha = 0.2 // EMA平滑系数，越大响应越快
+    private val minFps = 8 // 渲染帧率下限，防止过低
+    private val maxFps = 30 // 渲染帧率上限，防止过高
+    private val maxStep = 2.0 // 单次最大调整幅度，防止突变
+
     // 输入帧结构体
     private data class FrameData(
         val data: ByteArray,
@@ -144,6 +155,14 @@ class VideoDecoder(
             }
             override fun onOutputBufferAvailable(codec: MediaCodec, index: Int, info: MediaCodec.BufferInfo) {
                 if (!running) return
+                // 记录解码输出时间戳
+                val now = SystemClock.elapsedRealtime()
+                decodeTimestampLock.withLock {
+                    if (decodeTimestampQueue.size >= 20) {
+                        decodeTimestampQueue.removeFirst()
+                    }
+                    decodeTimestampQueue.addLast(now)
+                }
                 // 解码后帧入输出缓冲区，由渲染线程处理
                 val frame = DecodedFrame(codec, index, MediaCodec.BufferInfo().apply {
                     set(0, info.size, info.presentationTimeUs, info.flags)
@@ -168,6 +187,7 @@ class VideoDecoder(
         renderThread = Thread {
             var hasNotifiedFlutter = false
             var renderedFrameCount = 0 // 渲染帧计数器
+            val fpsAdjustInterval = 10 // 每渲染10帧调整一次帧率
             while (renderThreadRunning) {
                 // 计算每帧渲染间隔
                 val frameIntervalMs = if (renderFps > 0) 1000L / renderFps else 66L
@@ -182,6 +202,13 @@ class VideoDecoder(
                         mainHandler.post { onFrameRendered() }
                         hasNotifiedFlutter = true
                     }
+                    // 每渲染N帧动态调整一次帧率
+                    if (renderedFrameCount % fpsAdjustInterval == 0) {
+                        val measuredFps = calculateDecodeFps()
+                        val newFps = updateSmoothedFps(measuredFps)
+                        renderFps = newFps
+                        Log.i(TAG, "[AutoFps] measuredFps=$measuredFps, smoothedFps=$smoothedFps, renderFps=$renderFps")
+                    }
                 } catch (e: Exception) {
                     Log.e(TAG, "[RenderThread] Exception", e)
                 }
@@ -190,6 +217,8 @@ class VideoDecoder(
                 val sleepMs = frameIntervalMs - loopCost
                 if (sleepMs > 0) {
                     try { Thread.sleep(sleepMs) } catch (_: Exception) {}
+                } else {
+                    // 若解码极慢，sleepMs为负，直接进入下一帧，防止阻塞
                 }
             }
             // 清理剩余帧，防止内存泄漏
@@ -257,5 +286,34 @@ class VideoDecoder(
             surface.release()
         } catch (_: Exception) {}
     }
+
+    /**
+     * 计算最近N帧的平均解码帧率（fps）
+     */
+    private fun calculateDecodeFps(): Double {
+        decodeTimestampLock.withLock {
+            if (decodeTimestampQueue.size < 2) return renderFps.toDouble()
+            val first = decodeTimestampQueue.first()
+            val last = decodeTimestampQueue.last()
+            val frameCount = decodeTimestampQueue.size - 1
+            val durationMs = (last - first).coerceAtLeast(1L)
+            return frameCount * 1000.0 / durationMs
+        }
+    }
+
+    /**
+     * EMA平滑更新渲染帧率
+     * @param measuredFps 当前测得的解码帧率
+     * @return 平滑后的渲染帧率（取整）
+     */
+    private fun updateSmoothedFps(measuredFps: Double): Int {
+        // measuredFps边界保护
+        val safeFps = measuredFps.coerceIn(minFps.toDouble(), maxFps.toDouble())
+        val targetFps = alpha * safeFps + (1 - alpha) * smoothedFps
+        val delta = targetFps - smoothedFps
+        val step = delta.coerceIn(-maxStep, maxStep)
+        smoothedFps = (smoothedFps + step).coerceIn(minFps.toDouble(), maxFps.toDouble())
+        return smoothedFps.toInt()
+    }
     // endregion
 } 
\ No newline at end of file