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get_disto: add a '-o file' option to save a diff map

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also: -scale option is useful for using the maximum range.

Change-Id: I8ede7132b08ece7d3b6f699b710ab2ef3fb0b734
This commit is contained in:
Pascal Massimino
2016-08-30 15:03:08 +02:00
parent 85cd5d061c
commit 0de48e187d
1 changed files with 78 additions and 0 deletions
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78
extras/get_disto.c
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@@ -47,6 +47,35 @@ static size_t ReadPicture(const char* const filename, WebPPicture* const pic,
return ok ? data_size : 0;
}
// returns the max absolute difference
static int DiffScaleChannel(uint8_t* src1, int stride1,
const uint8_t* src2, int stride2,
int x_stride, int w, int h, int do_scaling) {
int x, y;
uint32_t max = 1;
for (y = 0; y < h; ++y) {
uint8_t* const ptr1 = src1 + y * stride1;
const uint8_t* const ptr2 = src2 + y * stride2;
for (x = 0; x < w * x_stride; x += x_stride) {
const uint32_t diff = abs(ptr1[x] - ptr2[x]);
if (diff > max) max = diff;
ptr1[x] = diff;
}
}
if (do_scaling) {
const uint32_t factor = (255u << 16) / max;
for (y = 0; y < h; ++y) {
uint8_t* const ptr1 = src1 + y * stride1;
for (x = 0; x < w * x_stride; x += x_stride) {
const uint32_t diff = (ptr1[x] * factor) >> 16;
ptr1[x] = diff;
}
}
}
return max;
}
static void Help(void) {
fprintf(stderr,
"Usage: get_disto [-ssim][-psnr][-alpha] compressed.webp orig.webp\n"
@@ -54,6 +83,8 @@ static void Help(void) {
" -psnr ..... print PSNR distortion (default)\n"
" -alpha .... preserve alpha plane\n"
" -h ........ this message\n"
" -o <file> . save the diff map as a WebP lossless file\n"
" -scale .... scale the difference map to fit [0..255] range\n"
" Also handles PNG, JPG and TIFF files, in addition to WebP.\n");
}
@@ -66,8 +97,10 @@ int main(int argc, const char *argv[]) {
int c;
int help = 0;
int keep_alpha = 0;
int scale = 0;
const char* name1 = NULL;
const char* name2 = NULL;
const char* output = NULL;
if (!WebPPictureInit(&pic1) || !WebPPictureInit(&pic2)) {
fprintf(stderr, "Can't init pictures\n");
@@ -81,9 +114,17 @@ int main(int argc, const char *argv[]) {
type = 0;
} else if (!strcmp(argv[c], "-alpha")) {
keep_alpha = 1;
} else if (!strcmp(argv[c], "-scale")) {
scale = 1;
} else if (!strcmp(argv[c], "-h")) {
help = 1;
ret = 0;
} else if (!strcmp(argv[c], "-o")) {
if (++c == argc) {
fprintf(stderr, "missing file name after %s option.\n", argv[c - 1]);
goto End;
}
output = argv[c];
} else if (name1 == NULL) {
name1 = argv[c];
} else {
@@ -115,6 +156,43 @@ int main(int argc, const char *argv[]) {
printf("%u %.2f %.2f %.2f %.2f %.2f\n",
(unsigned int)size1, disto[4],
disto[0], disto[1], disto[2], disto[3]);
if (output != NULL) {
uint8_t* data = NULL;
size_t data_size = 0;
if (pic1.use_argb != pic1.use_argb) {
fprintf(stderr, "Pictures are not in the same argb format. "
"Can't save the difference map.\n");
goto End;
}
if (pic1.use_argb) {
int n;
fprintf(stderr, "max absolute differences per channel: ");
for (n = 0; n < 3; ++n) { // skip the alpha channel
const int range = DiffScaleChannel((uint8_t*)pic1.argb + n,
pic1.argb_stride * 4,
(const uint8_t*)pic2.argb + n,
pic2.argb_stride * 4,
4, pic1.width, pic1.height, scale);
fprintf(stderr, "[%d]", range);
}
fprintf(stderr, "\n");
} else {
fprintf(stderr, "Can only compute the difference map in ARGB format.\n");
goto End;
}
data_size = WebPEncodeLosslessBGRA((const uint8_t*)pic1.argb,
pic1.width, pic1.height,
pic1.argb_stride * 4,
&data);
if (data_size == 0) {
fprintf(stderr, "Error during lossless encoding.\n");
goto End;
}
ret = ImgIoUtilWriteFile(output, data, data_size) ? 0 : 1;
WebPFree(data);
if (ret) goto End;
}
ret = 0;
End: