Working withAnimated Files {#tutorial_animations}

HandlingAnimated Image Files {#tutorial_animations}

In this tutorial, you will learn how to:

- Use cv::imreadanimation to load frames from animated files.

- Understand the structure and parameters of the cv::Animation structure.

- Use`cv::imreadanimation` to load frames from animated image files.

- Understand the structure and parameters of the`cv::Animation` structure.

- Display individual frames from an animation.

- Use cv::imwriteanimation to write cv::Animation to file.

- Use`cv::imwriteanimation` to write`cv::Animation` to a file.

Source Code

-**Downloadable code**: Click

[here](https://github.com/opencv/opencv/tree/4.x/samples/cpp/tutorial_code/imgcodecs/animations.cpp)

-**Code at glance:**

-**Code ataglance:**

@include samples/cpp/tutorial_code/imgcodecs/animations.cpp

@end_toggle

@add_toggle_python

-**Downloadable code**: Click

[here](https://github.com/opencv/opencv/tree/4.x/samples/python/tutorial_code/imgcodecs/animations.py)

-**Code at glance:**

-**Code ataglance:**

@include samples/python/tutorial_code/imgcodecs/animations.py

@end_toggle

The cv::imreadanimation function is used to load multiple frames from animated files (such as AVIF, APNG, or WebP) into an cv::Animation structure.

This function is especially useful for handling animated images, where each frame is a separate image that can be processed individually.

CV_EXPORTS_Wboolimreadanimation(const String& filename, CV_OUT Animation& animation, int start = 0, int count = INT16_MAX);

Explanation

1.**Initializing the Animation Structure**

Initializea`cv::Animation` structure to hold the frames from the animated image file.

@add_toggle_cpp

@snippet cpp/tutorial_code/imgcodecs/animations.cpp init_animation

@end_toggle

@add_toggle_python

@snippet python/tutorial_code/imgcodecs/animations.py init_animation

@end_toggle

2.**Loading Frames**

Use cv::imreadanimation to load frames from the specified file. Here, we load all frames from an animated WebP image.

Use`cv::imreadanimation` to load frames from the specified file. Here, we load all frames from an animated WebP image.

@add_toggle_cpp

@snippet cpp/tutorial_code/imgcodecs/animations.cpp read_animation

The cv::imreadanimation and cv::imwriteanimation functions make it easy to work with animatedimagesby loading frames intoancv::Animation structure, allowing frame-by-frame processing.

With these functions, you can load, process, and save frames from animatedformatslike AVIF, APNG, and WebP.

The`cv::imreadanimation` and`cv::imwriteanimation` functions make it easy to work with animatedimage filesby loading frames intoa`cv::Animation` structure, allowing frame-by-frame processing.

With these functions, you can load, process, and save frames from animatedimage fileslike GIF, AVIF, APNG, and WebP.

CV_EXPORTS_Wboolimreadmulti(const String& filename, CV_OUT std::vector<Mat>& mats,int start,int count,int flags = IMREAD_ANYCOLOR);

CV_EXPORTS_Wboolimreadanimation(const String& filename, CV_OUT Animation& animation,int start =0,int count = INT16_MAX);

returnfalse;

}

m_animation.durations.push_back(decoder_->duration);

m_animation.durations.push_back(decoder_->imageTiming.durationInTimescales);

if (decoder_->image->exif.size >0) {

m_exif.parseExif(decoder_->image->exif.data, decoder_->image->exif.size);

const std::vector<int> &params) {

Animation animation;

animation.frames = img_vec;

for (size_t i =0; i < animation.frames.size(); i++)

{

animation.durations.push_back(timestamp);

animation.durations.push_back(1000);

}

returnwriteanimation(animation, params);

}

images.emplace_back(ConvertToAvif(img, do_lossless, bit_depth));

}

int timestamp =0;

for (size_t i =0; i < images.size(); i++)

{

OPENCV_AVIF_CHECK_STATUS(

avifEncoderAddImage(encoder_, images[i].get(),timestamp, flag),

avifEncoderAddImage(encoder_, images[i].get(),animation.durations[i], flag),

encoder_);

timestamp += animation.durations[i];

}

encoder_->timescale =1000;

virtualboolcheckSignature(const String& signature)const;

Animationanimation()const {return m_animation; };

constAnimation&animation()const {return m_animation; };

}

Animation animation;

bool success =imreadanimation(filename, animation);

if (!success) {

std::cerr <<"Failed to load animation frames\n";

frames= []

durations= []

foriinrange(10):

frame=image.copy()

cv.putText(frame,f"Frame{i}", (30,80),cv.FONT_HERSHEY_SIMPLEX,1.5, (255,100,0,255),2)

cv.imwriteanimation(filename,animation_to_save, [cv.IMWRITE_WEBP_QUALITY,100])

animation=cv.Animation()

success,animation=cv.imreadanimation(filename)

ifnotsuccess:

print("Failed to load animation frames")