From 860bc68bdba5410c5afe409b6ab078fc6c0de575 Mon Sep 17 00:00:00 2001
From: Takashi Yano <takashi.yano@nifty.ne.jp>
Date: Sun, 24 Mar 2024 12:01:04 +0900
Subject: [PATCH] Fix race issue among decoding threads which causes broken
 frame.

Trim event timings for multi-thread cooperation.
---
 codec/decoder/plus/src/welsDecoderExt.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/codec/decoder/plus/src/welsDecoderExt.cpp b/codec/decoder/plus/src/welsDecoderExt.cpp
index 22e4fbd59..0cdd005f7 100644
--- a/codec/decoder/plus/src/welsDecoderExt.cpp
+++ b/codec/decoder/plus/src/welsDecoderExt.cpp
@@ -693,9 +693,11 @@ DECODING_STATE CWelsDecoder::DecodeFrameNoDelay (const unsigned char* kpSrc,
     SBufferInfo* pDstInfo) {
   int iRet = dsErrorFree;
   if (m_iThreadCount >= 1) {
+    SET_EVENT (&m_sReleaseBufferEvent);
     iRet = ThreadDecodeFrameInternal (kpSrc, kiSrcLen, ppDst, pDstInfo);
     if (m_sReoderingStatus.iNumOfPicts) {
       WAIT_EVENT (&m_sBufferingEvent, WELS_DEC_THREAD_WAIT_INFINITE);
+      RESET_EVENT (&m_sBufferingEvent);
       RESET_EVENT (&m_sReleaseBufferEvent);
       if (!m_sReoderingStatus.bHasBSlice) {
         if (m_sReoderingStatus.iNumOfPicts > 1) {
@@ -705,7 +707,6 @@ DECODING_STATE CWelsDecoder::DecodeFrameNoDelay (const unsigned char* kpSrc,
       else {
         ReleaseBufferedReadyPictureReorder (NULL, ppDst, pDstInfo);
       }
-      SET_EVENT(&m_sReleaseBufferEvent);
     }
     return (DECODING_STATE)iRet;
   }
@@ -791,6 +792,10 @@ DECODING_STATE CWelsDecoder::DecodeFrame2WithCtx (PWelsDecoderContext pDecContex
   pDecContext->iFrameNum = -1; //initialize
 #endif
 
+  if (GetThreadCount (pDecContext) >= 1) {
+    WAIT_EVENT (&m_sReleaseBufferEvent, WELS_DEC_THREAD_WAIT_INFINITE);
+  }
+
   pDecContext->iFeedbackTidInAu = -1; //initialize
   pDecContext->iFeedbackNalRefIdc = -1; //initialize
   if (pDstInfo) {
@@ -873,8 +878,6 @@ DECODING_STATE CWelsDecoder::DecodeFrame2WithCtx (PWelsDecoderContext pDecContex
 
     OutputStatisticsLog (*pDecContext->pDecoderStatistics);
     if (GetThreadCount (pDecContext) >= 1) {
-      WAIT_EVENT (&m_sReleaseBufferEvent, WELS_DEC_THREAD_WAIT_INFINITE);
-      RESET_EVENT (&m_sBufferingEvent);
       BufferingReadyPicture (pDecContext, ppDst, pDstInfo);
       SET_EVENT (&m_sBufferingEvent);
     } else {
@@ -899,8 +902,6 @@ DECODING_STATE CWelsDecoder::DecodeFrame2WithCtx (PWelsDecoderContext pDecContex
   pDecContext->dDecTime += (iEnd - iStart) / 1e3;
 
   if (GetThreadCount (pDecContext) >= 1) {
-    WAIT_EVENT (&m_sReleaseBufferEvent, WELS_DEC_THREAD_WAIT_INFINITE);
-    RESET_EVENT (&m_sBufferingEvent);
     BufferingReadyPicture (pDecContext, ppDst, pDstInfo);
     SET_EVENT (&m_sBufferingEvent);
   } else {