refactor: 💡 (xgplayer-mp4-loader) 重构音频分组策略

bytedance · Apr 9, 2024 · 6f9b066 · 6f9b066
1 parent d060a12
commit 6f9b066
Showing 1 changed file with 22 additions and 57 deletions.
diff --git a/packages/xgplayer-mp4-loader/src/utils.js b/packages/xgplayer-mp4-loader/src/utils.js
@@ -235,7 +235,11 @@ function getSegments (
       range: [segFrames[0].offset, lastFrame.offset + lastFrame.size - 1],
       frames: segFrames
     })
-    time = 0
+
+    if (audioGroupingStrategy !== 1) {
+      time = 0
+    }
+
     segFrames = []
   }
 
@@ -259,70 +263,31 @@ function getSegments (
     gopMinPtsArr = []
     gopMaxPtsFrameIdxArr = []
     let duration = segmentDurations[0] || segDuration
-    let useGroupStartStrategy = audioGroupingStrategy === 1
-    const vSegments = videoSegments.map((v, i, arr) => {
-      if (
-        (i === 0 && arr[i].startTime > segDuration) /* 第一帧开始时间太晚 */ ||
-        (i > 0 && arr[i].startTime !== arr[i - 1].endTime) /* 中间有GAP不连贯 */
-      ) {
-        useGroupStartStrategy = false
-      }
-      return {
-        startTime: v.startTime,
-        endTime: v.endTime,
-        duration: v.duration
-      }
-    })
 
-    if (useGroupStartStrategy) {
-      if (frames.length > 0) {
-        const lastVFrame = videoSegments[videoSegments.length - 1]
-        const lastAFrame = frames[frames.length - 1]
-        const audioEndTime = (lastAFrame.pts + lastAFrame.duration) / timescale
-
-        if (!lastVFrame || lastVFrame.endTime < audioEndTime) {
-          let lastVSeg = vSegments.length ? vSegments[vSegments.length - 1] : null
-          // 补齐音视频对应的分组
-          do {
-            const startTime = lastVSeg?.endTime || 0
-            const endTime = startTime + segDuration
-            vSegments.push({
-              startTime,
-              endTime,
-              duration: segDuration
-            })
-            lastVSeg = vSegments[vSegments.length - 1]
-          } while (lastVSeg.endTime < audioEndTime)
-        }
-      }
-      for (let i = 0; i < l; i++) {
+    if (audioGroupingStrategy === 1) {
+      for (let i = 0, nextEndTime; i < l; i++) {
         const curFrame = frames[i]
         const nextFrame = frames[i + 1]
         const isFinalFrame = i === l - 1
-        const curOrder = segments.length
         segFrames.push(curFrame)
+        time += curFrame.duration
+        const curEndTime = nextEndTime || time / timescale
+        // 这里使用下一帧的目的是将每个分组的起始音频帧应该覆盖或包含GOP的开始时间，
+        // MSE在remove buffer时会将gop结束时间点的那个音频帧删掉，这个策略就是为了
+        // 防止之后再添加新的Coded Frame Group时由于缺少了一帧音频容易产生Buffer gap
+        nextEndTime = (nextFrame ? time + nextFrame.duration : 0) / timescale
         if (
           isFinalFrame ||
-          // 这里使用下一帧的目的是将每个分组的起始音频帧应该覆盖或包含GOP的开始时间，
-          // MSE在remove buffer时会将gop开始时间点的所在的音频帧删掉，这个策略就是为了
-          // 防止之后再添加新的Coded Frame Group时由于缺少了一帧音频容易产生Buffer gap
-          vSegments[curOrder].endTime < (nextFrame.pts + nextFrame.duration) / timescale
-        ) {
-          const groupFirst = segFrames[0]
-          const groupLast = segFrames[segFrames.length - 1]
-          const groupDuration =
-            (groupLast.pts + groupLast.duration - groupFirst.pts) / timescale
-          gopMinPtsArr.push(groupFirst.pts)
-          gopMaxPtsFrameIdxArr.push(groupLast.index)
-          pushSegment(groupDuration, curOrder, curOrder)
-
-          console.log(
-            segments.length,
-            curOrder,
-            groupLast.duration / timescale,
-            vSegments[curOrder].startTime,
-            segments[curOrder].startTime
+          (
+            videoSegments[segments.length]
+              ? nextEndTime > videoSegments[segments.length].endTime /* 有视频帧，使用GOP时间戳进行分割 */
+              : nextEndTime - segFrames[0].pts / timescale >= duration /* 无视频帧（包含音频帧大于视频时长的剩余音频帧分组的场景），使用配置的切片时间或最后一个GOP时长进行分割 */
           )
+        ) {
+          gopMinPtsArr.push(segFrames[0].pts)
+          gopMaxPtsFrameIdxArr.push(segFrames[segFrames.length - 1].index)
+          pushSegment(curEndTime, segments.length, segments.length)
+          duration = segmentDurations[segments.length] || segDuration
         }
       }
     } else {