WPE fix: Avoid pruning buffered ranges already enqueued for playback

In WPE WebKit, the buffered range of the currentTime has high chances to have been internally enqueued for playback (an action that can't be undone, there's no way to unenqueue other than flushing the whole playback pipeline). If that range is pruned, an internal flush is triggered, but in order to keep playing from the currentTime onwards, the needed samples must be enqueued again at least since the previous sync sample. This can cause a lot of stress to the video decoder and generate stuttering. This patch solves the problem by avoiding pruning (deleting) ranges belonging to the same buffered range where the currentTime (or seek target) is.
Dash-Industry-Forum · Sep 8, 2022 · 8b603b4 · 8b603b4
1 parent 931ddf6
commit 8b603b4
Showing 1 changed file with 18 additions and 0 deletions.
diff --git a/src/streaming/controllers/BufferController.js b/src/streaming/controllers/BufferController.js
@@ -559,6 +559,24 @@ function BufferController(config) {
             if (currentTimeRequest) {
                 rangeStart = Math.max(currentTimeRequest.startTime + currentTimeRequest.duration, rangeStart);
             }
+
+            // Never remove the contiguous range of targetTime in order to avoid flushes & reenqueues in WebKit based browsers
+            const ua = navigator.userAgent.toLowerCase();
+            if (/webkit/.test(ua) && !/chrome/.test(ua) && !/windows phone/.test(ua)) {
+                for (var i = 0; i < ranges.length; i++) {
+                    if (ranges.start(i) <= targetTime && targetTime <= ranges.end(i)
+                        && ranges.start(i) <= rangeStart && rangeStart <= ranges.end(i)) {
+                        let oldRangeStart = rangeStart;
+                        if (i + 1 < ranges.length) {
+                            rangeStart = ranges.start(i+1);
+                        } else
+                            rangeStart = ranges.end(i) + 1;
+                        logger.debug("Buffered range [" + ranges.start(i) + ", " + ranges.end(i) + "] overlaps with targetTime " + targetTime + " and range to be pruned [" + oldRangeStart + ", " + endOfBuffer + "], using [" + rangeStart + ", " + endOfBuffer +"] instead");
+                        break;
+                    }
+                }
+            }
+
             if (rangeStart < endOfBuffer) {
                 return {
                     start: rangeStart,