我正在尝试计算12张图片之间的缩放效果。每张图片比前一张大100%。它接近完美,但在图像之间的过渡处存在问题。每个图像之间的缩放不流畅。请观看视频:http://youtu.be/dUBbDjewpO0
我认为指数表达式pow()由于某种原因不正确。这是PHP脚本,但我找不到问题所在:
渲染效果良好。
<?php
$imageFiles=array(
'1.jpg',
'2.jpg',
'3.jpg',
'4.jpg');
$targetFrameRate=$targetDuration='18';
$imageCount = count($imageFiles);
$totalFrames = ($targetFrameRate*$targetDuration);
$sourceIndex = 0;
$firstIndex = 1;
$lastIndex = $totalFrames; //==total frames
$currentScale = 1;//image scaling for first scale
$deltaScale = ((($imageCount-1)*($scaleFactor-$currentScale))/$totalFrames);
for ($i=$firstIndex; $i<=$lastIndex; $i++) {
// prepare filename
$filename = createImageFilename($i, $imageType);
// determine source..
if ($i == $firstIndex) {
$newSourceIndex = 0;
}
else if ($i == $lastIndex) {
$newSourceIndex = ($imageCount-1);
}
else {
$newSourceIndex = intval(($i*($imageCount-1))/$totalFrames);
}
// create frame..
if ($newSourceIndex != $sourceIndex) {
$sourceIndex = $newSourceIndex;
$currentScale = pow($scaleFactor, $sourceIndex);
$nextScale = pow($scaleFactor, ($sourceIndex+1));
$deltaScale = ((($imageCount-1)*($nextScale-$currentScale))/$totalFrames);
copyImage($imageFiles[$sourceIndex],
sprintf('%s/%s', $outputDir, $filename),
$imageWidth,
$imageHeight,
$imageType);
}
else {
createImage($imageFiles[$sourceIndex],
sprintf('%s/%s', $outputDir, $filename),
($currentScale/pow($scaleFactor, $sourceIndex)),
$imageWidth,
$imageHeight,
$imageType);
}
//DEBUG: buffer some values for optional debug-output
if (isDebugOutputEnabled()) {
$debug_idx[$i] = $filename;
$debug_inf[$i] = sprintf('sourceIndex=%d , scale=%01.2f<br />', $sourceIndex, $currentScale);
}
// advance..
$currentScale += $deltaScale;
}
?>
渲染效果良好。
shell_exec('ffmpeg -f image2 -i /var/www/htdocs/image2/i%d.jpg -s 1280x720 -movflags faststart -b:v 5500k -r 18 output.flv');