How to accurately obtain the duration of each frame in gif

[lxccc812]

111111.zip
I have a gif composed of multiple pictures. The duration of each picture is different. When I re-compose the gif, I need to know the duration of each picture.

Original gif::

When I use the im object to save, there is no problem with the duration of each image.

import os
from PIL import Image, ImageSequence
from PIL import GifImagePlugin
GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY

image_list = []

def test_gif_duration():
    im = Image.open(r'old\111111.gif')
    im.save(r'new\111111.gif', save_all=True)

Only use im objects to generate new gifs::

When I split the gif and put each image into a new list, the duration of each image in the resultant gif is also OK.

from PIL import Image, ImageSequence
from PIL import GifImagePlugin
GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY

image_list = []

def test_save_image_list():
    im = Image.open(r'\old\111111.gif')
    for frame in ImageSequence.Iterator(im):
        image_list.append(frame)

    image_list[0].save(
        r'new\111111.gif',
        save_all=True,
        append_images=image_list[1:]
    )
]

Gif generated with the new list::

The composite gif also seems to overlap, which may be caused by the transparent background. Let's not discuss this error first.

But when I fill the background or other operations on each image, the duration of each image in the composite gif seems to become the same time. This is different from the duration of each image in the initial gif.In addition, the old gif is in an endless loop (loop=0), and the repetition number of the newly synthesized gif has also changed to 1. I must add another attribute (loop=0) to ensure that it is the result I want.

from PIL import Image, ImageSequence
from PIL import GifImagePlugin
GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY

image_list = []

def test_save_image_list():
    im = Image.open(r'old\111111.gif')
    fill_color = (255, 255, 255)
    for frame in ImageSequence.Iterator(im):
        frame = frame.convert('RGBA')
        bg = Image.new(frame.mode[:-1], frame.size, fill_color)
        bg.paste(frame, frame.split()[-1])
        frame = bg

        # convert_frame = frame.convert('RGB')
        # convert_frame.thumbnail((150, 150))

        image_list.append(frame)

    image_list[0].save(
        r'new\111111.gif',
        save_all=True,
        append_images=image_list[1:],
        loop=0
    )

Gif generated after filling operation::

python 3.7.9
Pillow 9.4.0

Before that, I checked the question of #6259 . I think our situation is the same. Therefore, I need to know the correct duration of each frame in the multi-frame picture in the gif, rather than the duration of the first frame.

[radarhere]

You can get the frame.info["duration"] to find out the duration of each frame, create a list using those numbers, and then use that list for the duration keyword when saving.

from PIL import Image, ImageSequence
from PIL import GifImagePlugin
GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY

image_list = []

def test_save_image_list():
    im = Image.open(r'old\111111.gif')
    fill_color = (255, 255, 255)
    duration = []
    for frame in ImageSequence.Iterator(im):
        duration.append(frame.info["duration"])
        frame = frame.convert('RGBA')
        bg = Image.new(frame.mode[:-1], frame.size, fill_color)
        bg.paste(frame, frame.split()[-1])
        frame = bg

        # convert_frame = frame.convert('RGB')
        # convert_frame.thumbnail((150, 150))

        image_list.append(frame)

    image_list[0].save(
        r'new\111111.gif',
        save_all=True,
        append_images=image_list[1:],
        loop=0,
        duration=duration
    )

[lxccc812]

from PIL import Image, ImageSequence
from PIL import GifImagePlugin
GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY

image_list = []

def test_save_image_list():
    im = Image.open(r'old\111111.gif')
    fill_color = (255, 255, 255)
    for frame in ImageSequence.Iterator(im):
        print(f'before: {frame.info}')
        frame = frame.convert('RGBA')
        bg = Image.new(frame.mode[:-1], frame.size, fill_color)
        bg.paste(frame, frame.split()[-1])
        frame = bg

        # convert_frame = frame.convert('RGB')
        # convert_frame.thumbnail((150, 150))
        print(f'after: {frame.info}')
        image_list.append(frame)

    image_list[0].save(
        r'\new\111111.gif',
        save_all=True,
        append_images=image_list[1:],

        loop=0
    )

I got the following results

Can I put these attributes back

[radarhere]

Sure. frame.info is just a dictionary.

info_before = frame.info
frame = frame.convert('RGBA')
bg = Image.new(frame.mode[:-1], frame.size, fill_color)
bg.paste(frame, frame.split()[-1])
frame = bg

# convert_frame = frame.convert('RGB')
# convert_frame.thumbnail((150, 150))
frame.info = info_before

or if you want just duration,

duration_before = frame.info["duration"]
frame = frame.convert('RGBA')
bg = Image.new(frame.mode[:-1], frame.size, fill_color)
bg.paste(frame, frame.split()[-1])
frame = bg

# convert_frame = frame.convert('RGB')
# convert_frame.thumbnail((150, 150))
frame.info["duration"] = duration_before

[lxccc812]

Thank you for your answer. My problem has been solved