Cleanup FRAG_GAP error creation and inlcude current buffer length in forward gap buffer limit

Author: robwalch

api-extractor/report/hls.js.api.md

@@ -330,6 +330,8 @@ export class BaseStreamController extends TaskLoop implements NetworkComponentAP
     // (undocumented)
     protected getFwdBufferInfo(bufferable: Bufferable | null, type: PlaylistLevelType): BufferInfo | null;
     // (undocumented)
+    protected getFwdBufferInfoAtPos(bufferable: Bufferable | null, pos: number, type: PlaylistLevelType): BufferInfo | null;
+    // (undocumented)
     protected getInitialLiveFragment(levelDetails: LevelDetails, fragments: Array<Fragment>): Fragment | null;
     // (undocumented)
     protected getLevelDetails(): LevelDetails | undefined;
@@ -406,7 +408,9 @@ export class BaseStreamController extends TaskLoop implements NetworkComponentAP
     // (undocumented)
     protected recoverWorkerError(data: ErrorData): void;
     // (undocumented)
-    protected reduceMaxBufferLength(threshold?: number): boolean;
+    protected reduceLengthAndFlushBuffer(data: ErrorData): boolean;
+    // (undocumented)
+    protected reduceMaxBufferLength(threshold: number): boolean;
     // (undocumented)
     protected resetFragmentErrors(filterType: PlaylistLevelType): void;
     // (undocumented)

src/controller/base-stream-controller.ts

@@ -1166,9 +1166,10 @@ export default class BaseStreamController
       const curSNIdx = frag.sn - levelDetails.startSN;
       // Move fragPrevious forward to support forcing the next fragment to load
       // when the buffer catches up to a previously buffered range.
+      const fragState = this.fragmentTracker.getState(frag);
       if (
-        this.fragmentTracker.getState(frag) === FragmentState.OK ||
-        (frag.gap && frag.stats.aborted)
+        fragState === FragmentState.OK ||
+        (fragState === FragmentState.PARTIAL && frag.gap)
       ) {
         fragPrevious = frag;
       }

src/controller/error-controller.ts

@@ -303,7 +303,7 @@ export default class ErrorController implements NetworkComponentAPI {
             candidate !== hls.loadLevel &&
             levels[candidate].loadError === 0
           ) {
-            // Skip level switch if GAP tag is found in next level
+            // Skip level switch if GAP tag is found in next level at same position
             if (data.details === ErrorDetails.FRAG_GAP && data.frag) {
               const levelDetails = hls.levels[candidate].details;
               if (levelDetails) {

src/controller/stream-controller.ts

@@ -327,13 +327,16 @@ export default class StreamController
         }
         frag = this.getNextFragment(this.nextLoadPosition, levelDetails);
         if (gapStart && frag && !frag.gap && bufferInfo.nextStart) {
-          // Make sure this doesn't make the next buffer timerange exceed forward buffer length after a gap
+          // Media buffered after GAP tags should not make the next buffer timerange exceed forward buffer length
           const nextbufferInfo = this.getFwdBufferInfoAtPos(
             this.mediaBuffer ? this.mediaBuffer : this.media,
             bufferInfo.nextStart,
             PlaylistLevelType.MAIN
           );
-          if (nextbufferInfo !== null && nextbufferInfo.len > maxBufLen) {
+          if (
+            nextbufferInfo !== null &&
+            bufferLen + nextbufferInfo.len >= maxBufLen
+          ) {
             return;
           }
         }

src/loader/fragment-loader.ts

@@ -69,18 +69,7 @@ export default class FragmentLoader {
         this.loader.destroy();
       }
       if (frag.gap) {
-        frag.stats.aborted = true;
-        frag.stats.retry++;
-        reject(
-          new LoadError({
-            type: ErrorTypes.MEDIA_ERROR,
-            details: ErrorDetails.FRAG_GAP,
-            fatal: false,
-            frag,
-            error: new Error('GAP tag found'),
-            networkDetails: null,
-          })
-        );
+        reject(createGapLoadError(frag));
         return;
       }
       const loader =
@@ -191,19 +180,7 @@ export default class FragmentLoader {
         this.loader.destroy();
       }
       if (frag.gap || part.gap) {
-        frag.stats.aborted = true;
-        frag.stats.retry++;
-        reject(
-          new LoadError({
-            type: ErrorTypes.MEDIA_ERROR,
-            details: ErrorDetails.FRAG_GAP,
-            fatal: false,
-            frag,
-            part,
-            error: new Error(`GAP ${frag.gap ? 'tag' : 'attribute'} found`),
-            networkDetails: null,
-          })
-        );
+        reject(createGapLoadError(frag, part));
         return;
       }
       const loader =
@@ -373,6 +350,22 @@ function createLoaderContext(
   return loaderContext;
 }
 
+function createGapLoadError(frag: Fragment, part?: Part): LoadError {
+  const error = new Error(`GAP ${frag.gap ? 'tag' : 'attribute'} found`);
+  const errorData: FragLoadFailResult = {
+    type: ErrorTypes.MEDIA_ERROR,
+    details: ErrorDetails.FRAG_GAP,
+    fatal: false,
+    frag,
+    error,
+    networkDetails: null,
+  };
+  if (part) {
+    errorData.part = part;
+  }
+  return new LoadError(errorData);
+}
+
 export class LoadError extends Error {
   public readonly data: FragLoadFailResult;
   constructor(data: FragLoadFailResult) {