[Google AI Studio] Time-Saving Cooking No. 41: An app to convert MP4, MOV, GIF, and APNG formats to APNG format

In the previous "Time-Saving Cooking No. 40," I released an app that loads animated GIF files and converts them to APNG format.

While actually using it, the honest truth is that I wanted to support other formats as well.
So, this time, as a version upgrade, I have added support for loading MP4 and MOV files.
Furthermore, in addition to the GIF support from last time, it now also supports APNG as an output file format.

How to use

I named the app
"MP4, MOV, GIF & APNG TO APNG PRO"
.

It does exactly what it says: it loads MP4 / MOV / GIF / APNG format files and outputs them as APNG format.

1. Loading files

When you launch the app, the following screen will appear.
Drag and drop the file you want to load into the "IMPORT SOURCE" box on the screen.
Alternatively, you can click the "+" button and select a file from the file list.

Once loading is complete, a preview will automatically appear and the video will play.

2. Converting to APNG

To convert to APNG format, click the "Generate APNG" button.
A progress bar will appear during conversion so you can check the processing status.

When conversion is complete, the "Download APNG" button will appear.

3. Downloading

Click the "Download APNG" button to download the converted APNG file.

This app includes:

• a frame trimming function (time direction) to specify the start frame to end frame

• a crop function (spatial direction) to cut out a portion of the screen

both of which are provided.

The following is a manual summarizing the operations.
The basic operations are the same as "Time-Saving Cooking No. 40", so please refer to that for detailed explanations with images.

MP4, MOV, GIF & APNG TO APNG PRO Operation Manual

This app is a professional tool for converting and editing various video and animation formats into high-quality "Animated PNG (APNG)". It is equipped with a limit check function that is particularly ideal for creating LINE animated stickers.

1. Import (Import Source)

Drag and drop a file into the drop zone in the center of the screen, or click to select a file.

• Supported formats: MP4, MOV (iPhone video supported), GIF, APNG

• Automatic analysis: After loading, all frames are expanded and the preview starts.

2. Preview Area (Main Preview)

Used for checking loaded data and displaying editing results in real-time.

• Background switching: You can switch the background to "Transparency Check," "White," or "Black" using the icon in the upper right. This is useful for checking transparent materials.

• Playback controls: Use the buttons at the bottom to play/pause, advance frame-by-frame, and check the current frame number.

• Reset: Use the "Reset Media" button to discard the current data and return to the initial screen.

3. Configuration (Configuration - Sidebar)

■ Selected Range

Specify the start and end points of the animation to be exported.

• Set Start / Set End: Sets the currently previewed frame as the start/end position.

• +20f / -20f: Quickly expand/shrink the selected range by 20 frames.

■ Crop Mode

A feature to crop a portion of an image and export it.

• LINE Frame Rule (LINE Sticker validation):
  When turned ON, it validates in real-time whether the image meets the LINE sticker requirements (max 320x270px, and at least one side must be 270px or more).

• W / H Slider: Adjusts the width and height of the crop area.

• X / Y Slider: Adjusts the position of the crop area.

Both support numerical input. Additionally, for the X / Y sliders, I have made it possible to adjust the crop frame by dragging it on the preview.

■ Export Settings

• Export Quality:

  • Lossless: Outputs in 24-bit + alpha channel without reducing image quality.

  • 256 / 128 / 64 Colors: Reduces file size by limiting the number of colors.

• Loop Count:
  Specifies the number of playbacks. Setting it to "0" results in an infinite loop.

4. Timeline and Filmstrip

• Filmstrip: Displays thumbnails of all frames. You can jump instantly to the clicked position.

• Select All: Clears the range selection and resets all frames to a selected state.

• Seek Bar: The blue highlighted area indicates the range to be exported.

• Selection Duration:
  Displays how many seconds the current selection will be as an animation. It is ideal for checking the "within 4 seconds" limit for items like LINE stickers.

5. Generate & Download

• Generate APNG: Starts the conversion based on your settings. Progress is displayed as a percentage during conversion.

• Download APNG: Appears after the conversion is complete. Click to save the created APNG file.

Reference: Converting from APNG format to animated GIF

If you want to paste it on the web, the animated GIF format may be more convenient. There is a conversion app available, so please feel free to use it.

App URL

This app is published at the following URL.

The shared version is here.

Update Information

20260713: Adjusted the app because a bug had occurred. Specifically, I addressed issues that were occurring with file loading and playback.

Summary: From smartphone videos to LINE animated stickers

With support for loading MP4 / MOV files, it is now possible to convert videos shot on Android or iPhone directly to APNG.
You can easily convert videos shot with your smartphone camera or videos processed with apps into materials for LINE animated stickers.

However, LINE stickers have strict restrictions such as frame count, playback time, and file size.
This app includes:

• Frame range trimming

• Size adjustment by cropping

• Reducing file size by limiting the number of colors

• Visualization of playback time

By combining features like these, I have made it possible to perform a certain degree of adjustments, but for more rigorous adjustments, please use the dedicated app I have provided.

In any case, this has really helped establish an environment where the entire flow of
video generation → editing → APNG conversion → LINE sticker registration
can be completed within a browser.

If you want to create stickers using smartphone videos or generative AI videos,
please use this as a reference.

That is all!