Allow newly created codecs to be reclaimed if the system is out of re…

…sources

index.src.html

@@ -3696,7 +3696,7 @@
 :: The presentation timestamp, given in microseconds. For decode,
     timestamp is copied from the {{EncodedVideoChunk}} corresponding
     to this {{VideoFrame}}. For encode, timestamp is copied to the
-    {{EncodedVideoChunk}}s corresponding to this {{VideoFrame}}. 
+    {{EncodedVideoChunk}}s corresponding to this {{VideoFrame}}.
 
     The {{VideoFrame/timestamp}} getter steps are to return
     {{VideoFrame/[[timestamp]]}}.
@@ -6035,7 +6035,8 @@
 received a call to `encode()`, `decode()`, `configure()`, `flush()` or `reset()`
 in the past `10 seconds`, or has called its `output()` callback in the past `10
 seconds`. Addionally, {{VideoEncoder}}s are considered [=active=] if they are
-making progress in encoding queued {{VideoFrame}}s.
+making progress in encoding queued {{VideoFrame}}s. Newly created codecs are not
+considered [=active=] until they call an output callback for the first time.
 
 NOTE: Encoding large {{VideoFrame}}s can take more than `10s` per frame. The
 special case for {{VideoEncoder}}s ensures that they are not reclaimed if more