From PNGs to APNGs

[jay123210599]

I have 227 PNGs. I want to make APNGs out of them where each APNG has 50 frames in them. I also want to make all of the APNGs in one setting. How do I do that using ffmpeg?

[StainlessS]

"From APNGs from PNGs",

Typo ?, Maybe "To APNGs from PNGs", or "From PNGs to APNGs".

Select EDIT, Advanced EDIT, on first post to edit thread title.

[Balling]

APNG implementaion in ffmpeg is subpar. You use https://apngasm.sourceforge.net/

[GeoffreyA]

Originally Posted by Balling

APNG implementaion in ffmpeg is subpar. You use https://apngasm.sourceforge.net/

Seeing this now, Balling's solution would be the way to go and looks far simpler.

[jay123210599]

Originally Posted by Balling

APNG implementaion in ffmpeg is subpar. You use https://apngasm.sourceforge.net/

I don't want any delays between my frames.

[huhn]

APNG without a delay makes no sense the delay is just a different word for FPS calculated differently.

[GeoffreyA]

Originally Posted by jay123210599

I don't want any delays between my frames.

As huhn points out, you can use a delay (0,041708375 should == 23.976 fps). Alternatively, my method works but requires editing the start and end variables.

[jay123210599]

Well, the default frame delay is 1/10 sec. How do I adjust it so my output APNG has 23.976 fps?

Also, which compressions for the tools are lossless, zlib, 7zip, or Zopfli? How does the number of iterations affect the compression/speed/quality? If I choose to optimize the palette and/or original color type of the PNGs, will it affect the quality of the APNG?

[GeoffreyA]

Originally Posted by jay123210599

Well, the default frame delay is 1/10 sec. How do I adjust it so my output APNG has 23.976 fps?

Also, which compressions for the tools are lossless, zlib, 7zip, or Zopfli? How does the number of iterations affect the compression/speed/quality? If I choose to optimize the palette and/or original color type of the PNGs, will it affect the quality of the APNG?

I'm not at the computer now to test it, but put in that value I posted, 0,041708375, and I reckon it should give 23.976 fps. As for the compression, try a few PNGs to convert to APNG, seeing which gives the better size; 7zip or Zopfli might have the edge. More iterations should yield better compression, but beyond some level, it will be diminishing returns.

[GeoffreyA]

Here's a working method for the time being. I tried to do it all automatically, but nested FOR loops are problematic in Windows batch files. So, you will have to change the "start" and "end" variables each time. The first time would be "start=1" and "end=50" and the second time, "start=51" and "end=100" and so on. Your filenames will have to be in the format of "1.png" and so forth, starting from 1. Please run this on a copy of your original folder in case something gets accidentally overwritten. I'll see if I can improve to do everything automatically.

setlocal EnableDelayedExpansion

set start=1
set end=50

mkdir "OUT"

(for /l %%i in (!start!, 1, !end!) do @echo file %%i.png) > "Jay2025.txt"

ffmpeg -f concat -r 23.976 -i "Jay2025.txt" "OUT\FINAL_%RANDOM%.apng"

pause

[Z2697]

they are lossless

[Z2697]

Shouldn't it be 1001/24000 = 0.0417833333333333333...?

[GeoffreyA]

Originally Posted by Z2697

Shouldn't it be 1001/24000 = 0.0417833333333333333...?

You are correct. I took the lazy option of dividing by 23.976.

[Z2697]

Why not test yourself?
You have no computer?

[poisondeathray]

My comments for "pallete optimization" for PNG were "in general" . It's a commonly used lossy technique for web graphics

If you're referring to apngasm specifically , the optimizations used there should be lossless according to the instructions.

Some optimizations used in APNG Assembler might re-sort the
palette, or change the color type from RGBA and RGB modes
to RGB and indexed modes. Those optimizations are only performed
when they are lossless, but if you want to avoid changing the
palette or colortype, use those switches to turn them off:

/kp : keep palette
/kc : keep color type

As usual, just read the instructions and/or test it yourself

[GeoffreyA]

Originally Posted by poisondeathray

My comments for "pallete optimization" for PNG were "in general" . It's a commonly used lossy technique for web graphics

If you're referring to apngasm specifically , the optimizations used there should be lossless according to the instructions.

Noted. I didn't read the Readme.

[jay123210599]

Here are my test files: https://www.mediafire.com/file/2ooty..._APNGs.7z/file

1-1 and 2-1 uses both color and palette optimization.

1-2 and 2-2 does use color nor palette optimization.

1-3 and 2-3 only uses palette optimization.

1-4 and 2-4 only uses color optimization.

All of them use zlib for compression.

[GeoffreyA]

Originally Posted by jay123210599

Here are my test files: https://www.mediafire.com/file/2ooty..._APNGs.7z/file

1-1 and 2-1 uses both color and palette optimization.

1-2 and 2-2 does use color nor palette optimization.

1-3 and 2-3 only uses palette optimization.

1-4 and 2-4 only uses color optimization.

All of them use zlib for compression.

Good job on the testing, and well organised. Looks like it's of no use turning on those settings because the files are exactly the same size; even the hashes are identical.

I must say, Jay, I couldn't help but smile seeing the second set of APNGs. Thanks for bringing a bit of humour to the evening. What anime is that?

[jay123210599]

Originally Posted by GeoffreyA

Good job on the testing, and well organised. Looks like it's of no use turning on those settings because the files are exactly the same size; even the hashes are identical.

You mean the colors? How did you prove they were the same?

[GeoffreyA]

Originally Posted by jay123210599

You mean the colors? How did you prove they were the same?

I didn't test the colours. I just looked at the file sizes and hashes in 7-Zip. Whether they are the same as the PNGs, I do not know, but they, the APNGs, are identical to each other.