[x265] [PATCH 3/3] Add function for histogram based scene change
Snehaa Giridharan
snehaa at multicorewareinc.com
Wed Nov 2 10:55:06 UTC 2022
>From b203e94ffc619a32ead6937a61471efa584afa71 Mon Sep 17 00:00:00 2001
From: ashok2022 <ashok at multicorewareinc.com>
Date: Wed, 26 Oct 2022 13:07:35 +0530
Subject: [PATCH] Add function for histogram based scene change
Signed-off-by: Snehaa Giridharan <snehaa at multicorewareinc.com>
---
source/encoder/slicetype.cpp | 166 ++++++++++++++++++++++++++++++++++-
source/encoder/slicetype.h | 3 +
2 files changed, 168 insertions(+), 1 deletion(-)
diff --git a/source/encoder/slicetype.cpp b/source/encoder/slicetype.cpp
index 9343593cc..79541e5cb 100644
--- a/source/encoder/slicetype.cpp
+++ b/source/encoder/slicetype.cpp
@@ -2398,7 +2398,10 @@ void Lookahead::slicetypeAnalyse(Lowres **frames,
bool bKeyframe)
int numAnalyzed = numFrames;
bool isScenecut = false;
- isScenecut = scenecut(frames, 0, 1, true, origNumFrames);
+ if (m_param->bHistBasedSceneCut)
+ isScenecut = histBasedScenecut(frames, 0, 1, origNumFrames);
+ else
+ isScenecut = scenecut(frames, 0, 1, true, origNumFrames);
/* When scenecut threshold is set, use scenecut detection for I frame
placements */
if (m_param->scenecutThreshold && isScenecut)
@@ -2710,6 +2713,167 @@ bool Lookahead::scenecutInternal(Lowres **frames,
int p0, int p1, bool bRealScen
return res;
}
+bool Lookahead::detectHistBasedSceneChange(Lowres **frames, int p0, int
p1, int p2)
+{
+ bool isAbruptChange;
+ bool isSceneChange;
+
+ Lowres *previousFrame = frames[p0];
+ Lowres *currentFrame = frames[p1];
+ Lowres *futureFrame = frames[p2];
+
+ currentFrame->bHistScenecutAnalyzed = true;
+
+ uint32_t **accHistDiffRunningAvgCb = m_accHistDiffRunningAvgCb;
+ uint32_t **accHistDiffRunningAvgCr = m_accHistDiffRunningAvgCr;
+ uint32_t **accHistDiffRunningAvg = m_accHistDiffRunningAvg;
+
+ uint8_t absIntDiffFuturePast = 0;
+ uint8_t absIntDiffFuturePresent = 0;
+ uint8_t absIntDiffPresentPast = 0;
+
+ uint32_t abruptChangeCount = 0;
+ uint32_t sceneChangeCount = 0;
+
+ uint32_t segmentWidth = frames[1]->widthFullRes /
NUMBER_OF_SEGMENTS_IN_WIDTH;
+ uint32_t segmentHeight = frames[1]->heightFullRes /
NUMBER_OF_SEGMENTS_IN_HEIGHT;
+
+ for (uint32_t segmentInFrameWidthIndex = 0; segmentInFrameWidthIndex <
NUMBER_OF_SEGMENTS_IN_WIDTH; segmentInFrameWidthIndex++)
+ {
+ for (uint32_t segmentInFrameHeightIndex = 0;
segmentInFrameHeightIndex < NUMBER_OF_SEGMENTS_IN_HEIGHT;
segmentInFrameHeightIndex++)
+ {
+ isAbruptChange = false;
+ isSceneChange = false;
+
+ // accumulative absolute histogram differences between the
past and current frame
+ uint32_t accHistDiff = 0;
+ uint32_t accHistDiffCb = 0;
+ uint32_t accHistDiffCr = 0;
+
+ uint32_t segmentWidthOffset = (segmentInFrameWidthIndex ==
NUMBER_OF_SEGMENTS_IN_WIDTH - 1) ?
+ frames[1]->widthFullRes - (NUMBER_OF_SEGMENTS_IN_WIDTH *
segmentWidth) : 0;
+
+ uint32_t segmentHeightOffset = (segmentInFrameHeightIndex ==
NUMBER_OF_SEGMENTS_IN_HEIGHT - 1) ?
+ frames[1]->heightFullRes - (NUMBER_OF_SEGMENTS_IN_HEIGHT *
segmentHeight) : 0;
+
+ segmentWidth += segmentWidthOffset;
+ segmentHeight += segmentHeightOffset;
+
+ uint32_t segmentThreshHold = (
+ ((X265_ABS((int64_t)currentFrame->picAvgVariance -
(int64_t)previousFrame->picAvgVariance)) > PICTURE_DIFF_VARIANCE_TH) &&
+ (currentFrame->picAvgVariance > PICTURE_VARIANCE_TH ||
previousFrame->picAvgVariance > PICTURE_VARIANCE_TH)) ?
+ HIGH_VAR_SCENE_CHANGE_TH * NUM64x64INPIC(segmentWidth,
segmentHeight) : LOW_VAR_SCENE_CHANGE_TH * NUM64x64INPIC(segmentWidth,
segmentHeight);
+
+ uint32_t segmentThreshHoldCb = (
+ ((X265_ABS((int64_t)currentFrame->picAvgVarianceCb -
(int64_t)previousFrame->picAvgVarianceCb)) >
PICTURE_DIFF_VARIANCE_CHROMA_TH) &&
+ (currentFrame->picAvgVarianceCb >
PICTURE_VARIANCE_CHROMA_TH || previousFrame->picAvgVarianceCb >
PICTURE_VARIANCE_CHROMA_TH)) ?
+ HIGH_VAR_SCENE_CHANGE_CHROMA_TH *
NUM64x64INPIC(segmentWidth, segmentHeight) : LOW_VAR_SCENE_CHANGE_CHROMA_TH
* NUM64x64INPIC(segmentWidth, segmentHeight);
+
+ uint32_t segmentThreshHoldCr = (
+ ((X265_ABS((int64_t)currentFrame->picAvgVarianceCr -
(int64_t)previousFrame->picAvgVarianceCr)) >
PICTURE_DIFF_VARIANCE_CHROMA_TH) &&
+ (currentFrame->picAvgVarianceCr >
PICTURE_VARIANCE_CHROMA_TH || previousFrame->picAvgVarianceCr >
PICTURE_VARIANCE_CHROMA_TH)) ?
+ HIGH_VAR_SCENE_CHANGE_CHROMA_TH *
NUM64x64INPIC(segmentWidth, segmentHeight) : LOW_VAR_SCENE_CHANGE_CHROMA_TH
* NUM64x64INPIC(segmentWidth, segmentHeight);
+
+ for (uint32_t bin = 0; bin < HISTOGRAM_NUMBER_OF_BINS; ++bin) {
+ accHistDiff +=
X265_ABS((int32_t)currentFrame->picHistogram[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0][bin]
-
(int32_t)previousFrame->picHistogram[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0][bin]);
+ accHistDiffCb +=
X265_ABS((int32_t)currentFrame->picHistogram[segmentInFrameWidthIndex][segmentInFrameHeightIndex][1][bin]
-
(int32_t)previousFrame->picHistogram[segmentInFrameWidthIndex][segmentInFrameHeightIndex][1][bin]);
+ accHistDiffCr +=
X265_ABS((int32_t)currentFrame->picHistogram[segmentInFrameWidthIndex][segmentInFrameHeightIndex][2][bin]
-
(int32_t)previousFrame->picHistogram[segmentInFrameWidthIndex][segmentInFrameHeightIndex][2][bin]);
+ }
+
+ if (m_resetRunningAvg) {
+
accHistDiffRunningAvg[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
= accHistDiff;
+
accHistDiffRunningAvgCb[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
= accHistDiffCb;
+
accHistDiffRunningAvgCr[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
= accHistDiffCr;
+ }
+
+ // difference between accumulative absolute histogram
differences and the running average at the current frame.
+ uint32_t accHistDiffError =
X265_ABS((int32_t)accHistDiffRunningAvg[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
- (int32_t)accHistDiff);
+ uint32_t accHistDiffErrorCb =
X265_ABS((int32_t)accHistDiffRunningAvgCb[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
- (int32_t)accHistDiffCb);
+ uint32_t accHistDiffErrorCr =
X265_ABS((int32_t)accHistDiffRunningAvgCr[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
- (int32_t)accHistDiffCr);
+
+ if ((accHistDiffError > segmentThreshHold && accHistDiff
>= accHistDiffError) ||
+ (accHistDiffErrorCb > segmentThreshHoldCb && accHistDiffCb
>= accHistDiffErrorCb) ||
+ (accHistDiffErrorCr > segmentThreshHoldCr && accHistDiffCr
>= accHistDiffErrorCr)) {
+
+ isAbruptChange = true;
+ }
+
+ if (isAbruptChange)
+ {
+ absIntDiffFuturePast =
(uint8_t)X265_ABS((int16_t)futureFrame->averageIntensityPerSegment[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0]
-
(int16_t)previousFrame->averageIntensityPerSegment[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0]);
+ absIntDiffFuturePresent =
(uint8_t)X265_ABS((int16_t)futureFrame->averageIntensityPerSegment[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0]
-
(int16_t)currentFrame->averageIntensityPerSegment[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0]);
+ absIntDiffPresentPast =
(uint8_t)X265_ABS((int16_t)currentFrame->averageIntensityPerSegment[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0]
-
(int16_t)previousFrame->averageIntensityPerSegment[segmentInFrameWidthIndex][segmentInFrameHeightIndex][0]);
+
+ if (absIntDiffFuturePresent >= FLASH_TH *
absIntDiffFuturePast && absIntDiffPresentPast >= FLASH_TH *
absIntDiffFuturePast) {
+ x265_log(m_param, X265_LOG_DEBUG, "Flash in frame# %i
, %i, %i, %i\n", currentFrame->frameNum, absIntDiffFuturePast,
absIntDiffFuturePresent, absIntDiffPresentPast);
+ }
+ else if (absIntDiffFuturePresent < FADE_TH &&
absIntDiffPresentPast < FADE_TH) {
+ x265_log(m_param, X265_LOG_DEBUG, "Fade in frame# %i ,
%i, %i, %i\n", currentFrame->frameNum, absIntDiffFuturePast,
absIntDiffFuturePresent, absIntDiffPresentPast);
+ }
+ else if (X265_ABS(absIntDiffFuturePresent -
absIntDiffPresentPast) < INTENSITY_CHANGE_TH && absIntDiffFuturePresent +
absIntDiffPresentPast >= absIntDiffFuturePast) {
+ x265_log(m_param, X265_LOG_DEBUG, "Intensity Change in
frame# %i , %i, %i, %i\n", currentFrame->frameNum, absIntDiffFuturePast,
absIntDiffFuturePresent, absIntDiffPresentPast);
+ }
+ else {
+ isSceneChange = true;
+ x265_log(m_param, X265_LOG_DEBUG, "Scene change in
frame# %i , %i, %i, %i\n", currentFrame->frameNum, absIntDiffFuturePast,
absIntDiffFuturePresent, absIntDiffPresentPast);
+ }
+
+ }
+ else {
+
accHistDiffRunningAvg[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
= (3 *
accHistDiffRunningAvg[segmentInFrameWidthIndex][segmentInFrameHeightIndex]
+ accHistDiff) / 4;
+ }
+
+ abruptChangeCount += isAbruptChange;
+ sceneChangeCount += isSceneChange;
+ }
+ }
+
+ if (abruptChangeCount >= m_segmentCountThreshold) {
+ m_resetRunningAvg = true;
+ }
+ else {
+ m_resetRunningAvg = false;
+ }
+
+ if ((sceneChangeCount >= m_segmentCountThreshold)) {
+ x265_log(m_param, X265_LOG_DEBUG, "Scene Change in Pic Number#
%i\n", currentFrame->frameNum);
+
+ return true;
+ }
+ else {
+ return false;
+ }
+
+}
+
+bool Lookahead::histBasedScenecut(Lowres **frames, int p0, int p1, int
numFrames)
+{
+ /* Only do analysis during a normal scenecut check. */
+ if (m_param->bframes)
+ {
+ int origmaxp1 = p0 + 1;
+ /* Look ahead to avoid coding short flashes as scenecuts. */
+ origmaxp1 += m_param->bframes;
+ int maxp1 = X265_MIN(origmaxp1, numFrames);
+
+ for (int cp1 = p0; cp1 < maxp1; cp1++)
+ {
+ if (frames[cp1 + 1]->bHistScenecutAnalyzed == true)
+ continue;
+
+ if (detectHistBasedSceneChange(frames, cp1, cp1 + 1, cp1 + 2))
+ {
+ /* If current frame is a Scenecut from p0 frame as well as
Scenecut from
+ * preceeding frame, mark it as a Scenecut */
+ frames[cp1+1]->bScenecut = true;
+ }
+ }
+
+ }
+
+ return frames[p1]->bScenecut;
+}
+
void Lookahead::slicetypePath(Lowres **frames, int length,
char(*best_paths)[X265_LOOKAHEAD_MAX + 1])
{
char paths[2][X265_LOOKAHEAD_MAX + 1];
diff --git a/source/encoder/slicetype.h b/source/encoder/slicetype.h
index 442063cf4..d0a39506a 100644
--- a/source/encoder/slicetype.h
+++ b/source/encoder/slicetype.h
@@ -232,6 +232,9 @@ protected:
bool scenecut(Lowres **frames, int p0, int p1, bool bRealScenecut,
int numFrames);
bool scenecutInternal(Lowres **frames, int p0, int p1, bool
bRealScenecut);
+ bool histBasedScenecut(Lowres **frames, int p0, int p1, int
numFrames);
+ bool detectHistBasedSceneChange(Lowres **frames, int p0, int p1,
int p2);
+
void slicetypePath(Lowres **frames, int length,
char(*best_paths)[X265_LOOKAHEAD_MAX + 1]);
int64_t slicetypePathCost(Lowres **frames, char *path, int64_t
threshold);
int64_t vbvFrameCost(Lowres **frames, int p0, int p1, int b);
--
2.37.2.windows.2
*Thanks and Regards,*
*Snehaa.GVideo Codec Engineer,Media & AI analytics
<https://multicorewareinc.com/>*
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