将 jpeg 转换为 gif 太长了 [英] Converting jpegs to gifs is too long
问题描述
我正在尝试使用从摄像机获取的 jpeg 制作 gif 动画.但是这个过程是虚幻的漫长.我使用了两个不同的库.首先是用原生 C++ 代码编写的，其次是 Java 的 一个.
I'm trying to make gif animation from jpegs I get from video camera. But this process is unreal long. I used two different libraries. First is written with native C++ code and second is Java's one.
我尽可能压缩帧，但即使这样也不能减少生成时间.
I compress frames as I can, but even this cannot reduce generating time.
本机库需要大约 80-100 秒，Java 需要大约 40-60 秒(我不知道 java 是如何快 2 倍，但日志向我显示了这个结果)5 秒的 16 fps 视频(每帧 80 帧)gif).
Native library takes about 80-100 seconds and Java's takes about 40-60 seconds (I don't know how java is 2 times faster, but logs show me this result) for 5 seconds video with 16 fps (80 frames per gif).
我根据 this 更改了一点 C++ 算法，因为我遇到了同样的问题(尝试两个版本都更改了一段代码并更改了整个 learn() 函数.
I changed a bit C++ algorithm according to this, because I got same problem (tried both versions with changing a piece of code and changing whole learn() function).
在这里你可以看到一段日志:
Here you can see piece of logs:
本机实现的最后三帧:
D/TimeUtils: Adding frame executed in 949ms
D/TimeUtils: Adding frame executed in 976ms
D/TimeUtils: Adding frame executed in 1028ms
D/TimeUtils: Creating gif with native library executed in 82553ms
Java 版本的最后三帧:
It's last three frames in Java's version:
D/TimeUtils: Adding frame executed in 541ms
D/TimeUtils: Adding frame executed in 513ms
D/TimeUtils: Adding frame executed in 521ms
D/TimeUtils: Creating gif with nbadal's library executed in 44811ms
也许还有一些其他有用的日志:
Maybe some other useful logs:
D/CameraActivity: Duration of the captured video is 5000ms
V/CameraActivity: Dimensions are 288w x 288h
D/CameraActivity: Final bitmaps count: 80
TimeUtils.java 包含用于检查方法执行多长时间的静态方法.
TimeUtils.java contains static methods to check how long method executes.
NativeGifConverter.java(仅转换函数):
NativeGifConverter.java (only converting function):
@Override public void createGifFile(String path, List<String> bitmapPaths) {
Bitmap bitmap = BitmapUtils.retrieve(bitmapPaths.get(0));
if (init(path, bitmap.getWidth(), bitmap.getHeight(), mNumColors, mQuality, mFrameDelay) != 0) {
Timber.e("Gifflen init failed");
return;
}
bitmap.recycle();
for (String bitmapPath : bitmapPaths) {
bitmap = howLong("Retrieving bitmap", () -> BitmapUtils.retrieve(bitmapPath));
final int width = bitmap.getWidth();
final int height = bitmap.getHeight();
final int[] pixels = new int[width * height];
final Bitmap finalBitmap = bitmap; // for counting time
howLongVoid("Retrieving pixels", () -> finalBitmap.getPixels(pixels, 0, width, 0, 0, width, height));
howLongVoid("Adding frame", () -> addFrame(pixels));
bitmap.recycle();
}
bitmap = null;
close();
}
NbadalGifConverter.java(仅转换函数):
NbadalGifConverter.java (only converting function):
@Override public void createGifFile(String path, List<String> bitmapsNames) {
final ByteArrayOutputStream bos = new ByteArrayOutputStream();
final AnimatedGifEncoder encoder = new AnimatedGifEncoder();
encoder.setDelay(mDelay);
encoder.setQuality(mQuality);
encoder.start(bos);
for (String bitmapName : bitmapsNames) {
final Bitmap bitmap = howLong("Retrieving bitmap", () -> BitmapUtils.retrieve(bitmapName));
howLongVoid("Adding frame", () -> encoder.addFrame(bitmap));
}
encoder.finish();
FileUtils.store(bos.toByteArray(), path.substring(0, path.lastIndexOf('.')) + ".gif");
}
我愿意向您展示另一段相关的代码.如有任何帮助，我将不胜感激.
I'm open to show you another related pieces of code. I would greatly appreciate any help.
[更新]
检索位图的日志:
D/TimeUtils: Retrieving bitmap executed in 3ms
D/TimeUtils: Retrieving bitmap executed in 3ms
D/TimeUtils: Retrieving bitmap executed in 4ms
推荐答案
首先感谢@Spektre 的回答:有效的 gif/图像颜色量化?
Firstly I have to thank to the @Spektre for this answer: Effective gif/image color quantization?
我和我的同事刚刚将它从 C++ 翻译成 Java.它在 4 倍的时间内显示出良好的结果.我会尝试改进它，但这已经比 AnimatedGifEncoder.java(我以前使用过)好得多了
My colleague and I just translated it from the C++ to the Java. It shows good results in 4x less time. I'll try to improve it, but this is already much better result, than AnimatedGifEncoder.java (I used before)
代码如下:
public static final int MAX_COLOR_COUNT = 65536;
/**
* @param pixels rgb 888
* @param palette int[256]
* @return indices of colors in palette
*/
private int[][][] createPalette(int[] pixels, int[] palette) {
final int[] histogram = new int[MAX_COLOR_COUNT]; // pixel count histogram
final int[] indices = new int[MAX_COLOR_COUNT]; // here index is color value
for (int i = 0; i < MAX_COLOR_COUNT; i++) {
indices[i] = i;
}
// creating histogram
for (int color : pixels) {
// 0001 1111 0111 1110 0000 1111 1000 0000 0000
color = ((color >> 3) & 0x1F) | ((color >> 5) & 0x7E0) | ((color >> 8) & 0xF800);
if (histogram[color] < Integer.MAX_VALUE) { // picture must be really big
histogram[color]++;
}
}
// removing zeros
int j = 0;
for (int i = 0; i < MAX_COLOR_COUNT; i++) {
histogram[j] = histogram[i];
indices[j] = indices[i];
if (histogram[j] != 0) {
j++;
}
}
final int histograms = j;
// bubble sort
for (int i = 1; i != 0; ) {
i = 0;
for (int x = 0, y = 1; y < histograms; x++, y++) {
if (histogram[x] < histogram[y]) {
i = histogram[x];
histogram[x] = histogram[y];
histogram[y] = i;
i = indices[x];
indices[x] = indices[y];
indices[y] = i;
i = 1;
}
}
}
final int[][][] colorMap = new int[32][64][32];
int colorTableIndex = 0, x = 0;
for (; x < histograms; x++) { // main colors
final int color = indices[x];
// 1f (16) = 0001 1111 (2)
// 3f (16) = 0011 1111 (2)
// (1111 1)(111 111)(1 1111)
final int b = color & 0x1f;
final int g = (color >> 5) & 0x3f;
final int r = (color >> 11) & 0x1f;
// skip if similar color already in palette[]
int a = 0, i = 0;
for (; i < colorTableIndex; i++) {
final byte tempB = (byte) ((palette[i] >> 3) & 0x1f);
final byte tempG = (byte) ((palette[i] >> 10) & 0x3f);
final byte tempR = (byte) ((palette[i] >> 19) & 0x1f);
// if difference between two colors is pretty small
// taxicab distance
int difference = tempB - b;
if (difference < 0) {
difference = -difference;
}
a = difference;
difference = tempG - g;
if (difference < 0) {
difference = -difference;
}
a += difference;
difference = tempR - r;
if (difference < 0) {
difference = -difference;
}
a += difference;
if (a <= 2) { // smaller than 16/8
a = 1;
break;
}
a = 0;
}
if (a != 0) {
colorMap[r][g][b] = i; // map to existing color
} else {
colorMap[r][g][b] = colorTableIndex; // map to new index
// 1111 1000 1111 1100 1111 1000
palette[colorTableIndex] = b << 3 | (g << 10) | (r << 19); // fill this index with new color
colorTableIndex++;
if (colorTableIndex >= 256/*palette.length*/) {
x++;
break;
}
}
} // colorTableIndex = new color table size
for (; x < histograms; x++) { // minor colors
final int color = indices[x];
final int b = color & 0x1f;
final int g = (color >> 5) & 0x3f;
final int r = (color >> 11) & 0x1f;
// find closest color
int minDistance = -1;
int colorIndex = 0;
for (int a, i = 0; i < colorTableIndex; i++) {
final byte tempB = (byte) ((palette[i] >> 3) & 0x1f);
final byte tempG = (byte) ((palette[i] >> 10) & 0x3f);
final byte tempR = (byte) ((palette[i] >> 19) & 0x1f);
int difference = tempB - b;
if (difference < 0) {
difference = -difference;
}
a = difference;
difference = tempG - g;
if (difference < 0) {
difference = -difference;
}
a += difference;
difference = tempR - r;
if (difference < 0) {
difference = -difference;
}
a += difference;
if ((minDistance < 0) || (minDistance > a)) {
minDistance = a;
colorIndex = i;
}
}
colorMap[r][g][b] = colorIndex;
}
return colorMap;
}
private byte[] map(int[] pixels, int[][][] colorMap) {
final int pixelsLength = pixels.length;
final byte[] mapped = new byte[pixelsLength];
for (int i = 0; i < pixelsLength; i++) {
final int color =
((pixels[i] >> 3) & 0x1F) | ((pixels[i] >> 5) & 0x7E0) | ((pixels[i] >> 8) & 0xF800);
final int b = color & 0x1f;
final int g = (color >> 5) & 0x3f;
final int r = (color >> 11) & 0x1f;
mapped[i] = (byte) colorMap[r][g][b];
}
return mapped;
}
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