bool VideoDecoder::seek(const Audio::Timestamp &time) {
if (!isSeekable())
return false;
// Stop all tracks so they can be seeked
if (isPlaying())
stopAudio();
// Do the actual seeking
if (!seekIntern(time))
return false;
// Seek any external track too
for (TrackListIterator it = _externalTracks.begin(); it != _externalTracks.end(); it++)
if (!(*it)->seek(time))
return false;
_lastTimeChange = time;
// Now that we've seeked, start all tracks again
// Also reset our start time
if (isPlaying()) {
startAudio();
_startTime = g_system->getMillis() - (time.msecs() / _playbackRate).toInt();
}
resetPauseStartTime();
findNextVideoTrack();
_needsUpdate = true;
return true;
}
const Graphics::Surface *AVIDecoder::decodeNextFrame() {
AVIVideoTrack *track = nullptr;
bool isReversed = false;
int frameNum = 0;
// Check whether the video is playing in revese
for (int idx = _videoTracks.size() - 1; idx >= 0; --idx) {
track = static_cast<AVIVideoTrack *>(_videoTracks[idx].track);
isReversed |= track->isReversed();
}
if (isReversed) {
// For reverse mode we need to keep seeking to just before the
// desired frame prior to actually decoding a frame
frameNum = getCurFrame();
seekIntern(track->getFrameTime(frameNum));
}
// Decode the next frame
const Graphics::Surface *frame = VideoDecoder::decodeNextFrame();
if (isReversed) {
// In reverse mode, set next frame to be the prior frame number
for (int idx = _videoTracks.size() - 1; idx >= 0; --idx) {
track = static_cast<AVIVideoTrack *>(_videoTracks[idx].track);
track->setCurFrame(frameNum - 1);
findNextVideoTrack();
}
}
return frame;
}
