best lossless codecs for a 30m video made of mostly still pictures

[Sentinel166]

Hi
As mentioned, my projects is mostly made of still pictures, at least staying still for a 4 or 5 seconds if not more, and transitions are quick.
I could see how ffv1 and utvideo don't cut it at all, even with big GOP numbers... the sum total of all project files, pictures and soundtracks, amounts to 2,6 Go. Invariably the resulting lossless file is more than 10 Go. The resolution is fullHD (1920 x 1080), 25 frames per second. But it SHOULD have interframe prediction: mostly still pictures, dammit.
If someone has a clue...

Thanks, Mehdi

[pandy]

264 or 265 in lossless/quasi lossless mode?

[poisondeathray]

Possibly lagarith with the "null frames" option enabled. It can essentially encodes 1 frame for each still frame.

But it depends on how your "project" is going to be used. Not all programs and players are compatible with lagarith null frames

The other option is specifying VFR timecodes (so each still frame is only 1 frame). But not all programs compatible with VFR - most players should be

The sum total of all project files, pictures and soundtracks, amounts to 2,6 Go. Invariably the resulting lossless file is more than 10 Go.

This might be "normal" because your project files likely used lossy compression to begin with

Lossess compression is with respect to the uncompressed (decoded) state . It would probably be ~ 20 Gb uncompressed

[Sentinel166]

still frames or not h264 managed well, and the file is the same size as the sum of all pictures+soundtracks. Interframe compression...
the footages are only a few limited in the whole project, and uncompressed.
I didn't know h265 (HEVC, right ?) had a loss mode.
I'm interested in testing lagarith, but on linux ? Doesn't seem to exist.

[poisondeathray]

still frames or not h264 managed well, and the file is the same size as the sum of all pictures+soundtracks. Interframe compression...
the footages are only a few limited in the whole project, and uncompressed.
I didn't know h265 (HEVC, right ?) had a loss mode.
I'm interested in testing lagarith, but on linux ? Doesn't seem to exist.

h265(hevc) using x265 has a lossless mode, but it's generally produces worse compression than x264

lagarith encoding is windows only, but libavcodec/ffmpeg can decode it

If you have transitions, the benefit becomes diminished

In a sample video test with images (e.g. slide show), RGB, no transitions - libx264rgb was ~ 20% larger than lagarith using null frames. But adding short 1sec cross dissolve transitions, lagarith was now ~ 5% larger than libx264rgb

The more still images or static content - the more lagarith null frames benefits; but the more different frames, it has to encode intra frame (lagarith does not use long GOP)

[jagabo]

lagarith... If you have transitions, the benefit becomes diminished

And if the video has been encoded with a lossy codec in the past many of the frames are no longer identical. If a single bit is different lagarith will not insert a null frame.

[4kblurayguru]

You can't get lossless in a small file. Throw away the transitions or use simpler ones, use 23.97fps timeline. Export in prores then use ffmpeg to compress to 720p using a CRF rate of 22-24 with audio settings AAC 128kbps.