commit 690667d26164261df846b84bb2f9ec0be40074be
parent 2dfe18ccee54772d732e6a8eb5d9328ca7af827c
Author: Chun-Min Chang <chun.m.chang@gmail.com>
Date: Sat, 25 Oct 2025 01:01:05 +0000
Bug 1995664 - Add a pref to wait for encoded results in WMF encoder r=media-playback-reviewers,azebrowski
This patch introduces a preference that forces the WMF encoder in realtime mode
to waitfor the encoded results before resolving the encode promise, instead of
resolving it upon receiving any system-encoder's response.
Note that there is a timer to ensure the encode promise is resolved within a
reasonable time. Hence, if no output is produced in time, the promise will be
resolved by the timer instead.
Differential Revision: https://phabricator.services.mozilla.com/D269528
Diffstat:
2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/dom/media/platforms/wmf/MFTEncoder.cpp b/dom/media/platforms/wmf/MFTEncoder.cpp
@@ -1243,12 +1243,16 @@ void MFTEncoder::EventHandler(MediaEventType aEventType, HRESULT aStatus) {
return;
}
+ const bool waitForOutput =
+ StaticPrefs::media_wmf_encoder_realtime_wait_for_output();
+
ProcessedResult result = processed.unwrap();
MFT_ENC_LOGV(
"%s processed: %s\n\tpending inputs: %zu\n\tinput needed: %zu\n\tpending "
- "outputs: %zu",
+ "outputs: %zu (waitForOutput=%s)",
MediaEventTypeStr(aEventType), MFTEncoder::EnumValueToString(result),
- mPendingInputs.size(), mNumNeedInput, mOutputs.Length());
+ mPendingInputs.size(), mNumNeedInput, mOutputs.Length(),
+ waitForOutput ? "yes" : "no");
switch (result) {
case ProcessedResult::AllAvailableInputsProcessed:
// Since mNumNeedInput was incremented in ProcessEvent(), before calling
@@ -1266,9 +1270,12 @@ void MFTEncoder::EventHandler(MediaEventType aEventType, HRESULT aStatus) {
if (mState == State::Encoding) {
// In realtime mode, we could resolve the encode promise only upon
// receiving an output. However, since the performance gain is minor,
- // it's not worth risking a scenario where the encode promise is
- // resolved by the timer callback if no output is produced in time.
- MaybeResolveOrRejectEncodePromise();
+ // unless the wait-for-output setting is enabled, it's better to prevent
+ // the encode promise from being resolved by the timer callback if no
+ // output is produced in time.
+ if (!waitForOutput) {
+ MaybeResolveOrRejectEncodePromise();
+ }
} else if (mState == State::PreDraining) {
if (mPendingInputs.empty()) {
MaybeResolveOrRejectPreDrainPromise();
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
@@ -11906,6 +11906,11 @@
value: true
mirror: always
+- name: media.wmf.encoder.realtime.wait-for-output
+ type: RelaxedAtomicBool
+ value: @IS_NIGHTLY_BUILD@
+ mirror: always
+
# Using Windows Media Foundation Media Engine for encrypted playback
# 0 : disable, 1 : enable for encrypted and clear,
# 2 : enable for encrypted only, 3 : enable for clear only
