Merge "Matroskaextractor: improve findThumbnails() time." into main am: faa2065048

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/3019097

Change-Id: Ic97088063203b638745e4544ee97922f24bef45c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/media/module/extractors/mkv/MatroskaExtractor.cpp b/media/module/extractors/mkv/MatroskaExtractor.cpp
index f9d2006..f326db1 100644
--- a/media/module/extractors/mkv/MatroskaExtractor.cpp
+++ b/media/module/extractors/mkv/MatroskaExtractor.cpp
@@ -2312,6 +2312,8 @@
         int64_t thumbnailTimeUs = 0;
         size_t maxBlockSize = 0;
         while (!iter.eos() && j < 20) {
+            int64_t blockTimeUs = iter.blockTimeUs();
+
             if (iter.block()->IsKey()) {
                 ++j;
 
@@ -2322,9 +2324,13 @@
 
                 if (blockSize > maxBlockSize) {
                     maxBlockSize = blockSize;
-                    thumbnailTimeUs = iter.blockTimeUs();
+                    thumbnailTimeUs = blockTimeUs;
                 }
             }
+            // Exit after 20s if we've already found at least one key frame.
+            if (blockTimeUs > 20000000 && maxBlockSize > 0) {
+                break;
+            }
             iter.advance();
         }
         AMediaFormat_setInt64(info->mMeta,