我希望能够改变动态 webp 的大小。 示例图片。 我发现本网站就能做到这一点。
那么我如何在自己的程序中实现类似的东西?我尝试使用 ImageMagick7 或 ffmpeg5,但失败了。
环境:
cat /etc/redhat-release
:CentOS Linux 版本 7.8.2003(核心)
1.尝试了ffmpeg:
[developer@Dev_Payment_229 ~]$ /opt/ffmpeg-5/ffmpeg -i b.webp -vf "scale=320:-1" b_320.webp
ffmpeg version 5.1.1-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
libavutil 57. 28.100 / 57. 28.100
libavcodec 59. 37.100 / 59. 37.100
libavformat 59. 27.100 / 59. 27.100
libavdevice 59. 7.100 / 59. 7.100
libavfilter 8. 44.100 / 8. 44.100
libswscale 6. 7.100 / 6. 7.100
libswresample 4. 7.100 / 4. 7.100
libpostproc 56. 6.100 / 56. 6.100
[webp @ 0x7686f40] skipping unsupported chunk: ANIM
[webp @ 0x7686f40] skipping unsupported chunk: ANMF
Last message repeated 10 times
[webp @ 0x7686f40] image data not found
[webp_pipe @ 0x7685700] Could not find codec parameters for stream 0 (Video: webp, none): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, webp_pipe, from 'b.webp':
Duration: N/A, bitrate: N/A
Stream #0:0: Video: webp, none, 25 fps, 25 tbr, 25 tbn
Stream mapping:
Stream #0:0 -> #0:0 (webp (native) -> webp (libwebp_anim))
Press [q] to stop, [?] for help
[webp @ 0x7697600] skipping unsupported chunk: ANIM
[webp @ 0x7697600] skipping unsupported chunk: ANMF
Last message repeated 10 times
[webp @ 0x7697600] image data not found
Error while decoding stream #0:0: Invalid data found when processing input
Cannot determine format of input stream 0:0 after EOF
Error marking filters as finished
Conversion failed!
看来ffmpeg无法识别这个动态的WebP图像。
2.尝试过 ImageMagick7
安装:
yum -y install libwebp-devel libwebp-tools
[root@Dev_FTP_241 developer]# yum list installed | grep webp
libwebp.x86_64 0.3.0-11.el7 @updates
libwebp-devel.x86_64 0.3.0-11.el7 @updates
libwebp-tools.x86_64 0.3.0-11.el7 @updates
源代码:
https://github.com/ImageMagick/ImageMagick/archive/refs/tags/7.1.1-0.tar.gz
tar -xvf ImageMagick-7.1.1-0.tar.gz
./configure --with-webp --prefix=/usr/local/imagemagick
make
make install
单个 WebP 可以调整大小:
[root@Dev_FTP_241 developer]# /usr/local/imagemagick/bin/convert -resize 480 simple.webp simple_480.webp
Decoded /tmp/magick-LNPdXgk2zDpiuU6Qv9CpDups3560EATh. Dimensions: 2160 x 608. Now saving...
Saved file /tmp/magick-Q8JHRZZOXdp1r1x187eftzsFlw8AqAuo
但动画 WebP 失败了:
[root@Dev_FTP_241 developer]# /usr/local/imagemagick/bin/convert -resize 480 b.webp b_480.webp
Error! Decoding of an animated WebP file is not supported.
Use webpmux to extract the individual frames or
vwebp to view this image.
Decoding of /tmp/magick-jMiy7ytmAnBzpS8UpafCQ5B44BjDTUSD failed.
Status: 4 (UNSUPPORTED_FEATURE)
convert: delegate failed `'dwebp' -pam '%i' -o '%o'' @ error/delegate.c/InvokeDelegate/1924.
convert: unable to open file '/tmp/magick-D-NMEGWU_a0IypZWwTpYiWIE61nteoig': No such file or directory @ error/constitute.c/ReadImage/786.
convert: no images defined `b_480.webp' @ error/convert.c/ConvertImageCommand/3342.
答案1
Google 的 cwebp 可以调整 WebP 图像的大小,但奇怪的是不能调整动画图像的大小。
也许重新缩放可以通过libvips 命令行界面如果不是,示例 sharp 脚本(使用 node.js 运行)可能如下所示:
#!/usr/bin/env node
import * as fs from 'node:fs';
import sharp from 'sharp';
const dir = await fs.promises.opendir('./source');
const buffers = [];
for await (const dirent of dir) {
if (dirent.isFile()) {
buffers.push([
dirent.name, fs.createReadStream('./source/'+dirent.name),
]);
}
}
const width = 128; // change to your target width
await fs.promises.mkdir('./resized/');
for (const _buf of buffers) {
const pipeline = sharp({ pages: -1, })
.resize({ width, height: width, fit: 'inside' })
.toFile('./resized/'+_buf[0]);
try {
await _buf[1].pipe(pipeline);
} catch (e) {
console.log('problem: '+e);
}
}
答案2
答案3
对于我来说,图像魔法是有效的,但你必须输入百分比的调整大小选项,否则 webp 会失去动画。
因此,如果原始尺寸为 512x512 而您想要 480x480,则必须先进行一些简单的计算:
480/512 * 100 = 93,75%
magick b_512.webp -resize 93.75% b_480.webp
您必须使用点而不是逗号作为小数分隔符......
答案4
使用 Python 脚本
安装python:
yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel libjpeg-turbo-devel readline-devel tk-devel gcc make
wget https://www.python.org/ftp/python/3.9.9/Python-3.9.9.tgz
tar -zxvf Python-3.9.9.tgz
cd Python-3.9.9
./configure --prefix=/usr/local/python3.9
make
make install
/usr/local/python3.9/bin/python3 -V
/usr/local/python3.9/bin/pip3 -V
安装枕头:
/usr/local/python3.9/bin/pip3 install pillow==9.5.0
创建.py:
vi resize.py
# coding:utf-8
# resize.py
import sys
from PIL import Image, ImageSequence
try:
height = int(sys.argv[1])
input_file = sys.argv[2]
output_file = sys.argv[3]
except IndexError:
print('Usage: python resize.py <height> <input_file> <output_file>')
print('Example: python resize.py 400 input.webp output.webp')
sys.exit(1)
# 加载动态 WebP 图像
image = Image.open(input_file)
# 计算新的高度(保持原始宽高比)
orig_width, orig_height = image.size
width = int(orig_width * (height / orig_height))
if height <= 0:
width = orig_width
height = orig_height
# 获取所有帧数据
frames = []
for frame in ImageSequence.Iterator(image):
frames.append(frame.copy())
if len(frames) > 1:
# print('多张')
# 缩放每个帧
new_frames = []
first_frame = frames[0]
for i in range(len(frames)):
new_frame = frames[i].resize((width, height))
new_frames.append(new_frame)
# 将动画 图像另存为文件
new_frames[0].save(
output_file,
save_all=True,
append_images=new_frames[1:],
)
else:
# print('单张')
# 缩放图像
new_img = image.resize((width, height))
# 保存新图像
new_img.save(output_file)
测试:
/usr/local/python3.9/bin/python3 resize.py 260 animated.webp ani_resize260.webp