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VIDEO: Fix QuickTime decoding of edits with mediaTime

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QuickTimeDecoder has a bug which causes the mediaTime offset to be
ignored when a track begins with an empty edit and is followed by an
edit with a non-zero mediaTime. This causes the KQ6 Mac opening movie
to start several tracks at unintended frames (they're never supposed to
be displayed) and the intended frames at the end of the edit to never
be displayed. (Bug #11085)
This commit is contained in:
sluicebox 2021-11-10 04:56:59 -06:00 committed by Filippos Karapetis
parent 6e3403464b
commit dcd537337b
2 changed files with 24 additions and 8 deletions
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31
video/qt_decoder.cpp
View File

@ -297,9 +297,9 @@ QuickTimeDecoder::VideoTrackHandler::VideoTrackHandler(QuickTimeDecoder *decoder
}
_curEdit = 0;
enterNewEditListEntry(false);
_curFrame = -1;
enterNewEditListEntry(true); // might set _curFrame
_durationOverride = -1;
_scaledSurface = 0;
_curPalette = 0;
@ -514,6 +514,9 @@ const Graphics::Surface *QuickTimeDecoder::VideoTrackHandler::decodeNextFrame()
return 0;
enterNewEditListEntry(true);
if (isEmptyEdit())
return 0;
}
const Graphics::Surface *frame = bufferNextFrame();
@ -697,14 +700,22 @@ uint32 QuickTimeDecoder::VideoTrackHandler::findKeyFrame(uint32 frame) const {
return frame;
}
void QuickTimeDecoder::VideoTrackHandler::enterNewEditListEntry(bool bufferFrames) {
// Bypass all empty edit lists first
while (!atLastEdit() && _parent->editList[_curEdit].mediaTime == -1)
_curEdit++;
bool QuickTimeDecoder::VideoTrackHandler::isEmptyEdit() const {
return (_parent->editList[_curEdit].mediaTime == -1);
}
void QuickTimeDecoder::VideoTrackHandler::enterNewEditListEntry(bool bufferFrames) {
if (atLastEdit())
return;
// if this is an empty edit then the only thing to do is set the
// time for the next frame, which is the duration of this edit.
if (isEmptyEdit()) {
_curFrame = -1;
_nextFrameStartTime = getCurEditTimeOffset() + getCurEditTrackDuration();
return;
}
uint32 mediaTime = _parent->editList[_curEdit].mediaTime;
uint32 frameNum = 0;
uint32 totalDuration = 0;
@ -792,8 +803,12 @@ const Graphics::Surface *QuickTimeDecoder::VideoTrackHandler::bufferNextFrame()
}
uint32 QuickTimeDecoder::VideoTrackHandler::getRateAdjustedFrameTime() const {
// Figure out what time the next frame is at taking the edit list rate into account
Common::Rational offsetFromEdit = Common::Rational(_nextFrameStartTime - getCurEditTimeOffset()) / _parent->editList[_curEdit].mediaRate;
// Figure out what time the next frame is at taking the edit list rate into account,
// unless this is an empty edit, in which case the rate isn't applicable.
Common::Rational offsetFromEdit = Common::Rational(_nextFrameStartTime - getCurEditTimeOffset());
if (!isEmptyEdit()) {
offsetFromEdit /= _parent->editList[_curEdit].mediaRate;
}
uint32 convertedTime = offsetFromEdit.toInt();
if ((offsetFromEdit.getNumerator() % offsetFromEdit.getDenominator()) > (offsetFromEdit.getDenominator() / 2))

1
video/qt_decoder.h
View File

@ -171,6 +171,7 @@ private:
Common::SeekableReadStream *getNextFramePacket(uint32 &descId);
uint32 getCurFrameDuration(); // media time
uint32 findKeyFrame(uint32 frame) const;
bool isEmptyEdit() const;
void enterNewEditListEntry(bool bufferFrames);
const Graphics::Surface *bufferNextFrame();
uint32 getRateAdjustedFrameTime() const; // media time