True Lossless Compression

[Wayneman101]

I have found many things about lossless compression but no definitive answer to my question. Is there any true lossless compression where you compress a video and get the same video back out pixel for pixel and sound for sound with absolutely no loss of quality even if its not perceptible? I have 4 TB of storage on my laptop so saving the most amount of space is not that important. If I cut 20% off a 40GB movie I will be extremely happy.

[poisondeathray]

I have found many things about lossless compression but no definitive answer to my question. Is there any true lossless compression where you compress a video and get the same video back out pixel for pixel and sound for sound with absolutely no loss of quality even if its not perceptible? I have 4 TB of storage on my laptop so saving the most amount of space is not that important. If I cut 20% off a 40GB movie I will be extremely happy.

Yes there is.

BUT - if you're starting with an already compressed video or audio, true mathematically lossless compression will only increase the filesize. "Lossless" in this context refers to compared to the video or audio in the uncompressed state (ie. decoded to uncompressed then re-compressed with lossless compression. So compared to the uncompressed state, a lossless codec will reduce the filesize)

If you don't know what you have , use mediainfo (view=>text)

But it sounds more like to me you just want to reduce the filesize with minimal quality loss

[KarMa]

I tend to believe OP has a Bluray copy, and is asking about lossless compression on a lossy video. In which case lossless will only make the file size bigger by 3/4/5+ times.

[Cornucopia]

To continue what pdr said, most videos use lossy compression, which is many times smaller than lossless compression. And one of the things they use in their format - in addition to perceptual guessing, etc. - is some form of lossless coding.

Most all lossless coding takes the redundancy out of a file (usually by first re-ordering the numbering structure to put like #s in a sequence and then use a shorthand substitution). So if a file has already had it's redundancy removed, there is no more to remove. AKA no more compression to be gained, by further lossless coding. You can't further re-squeeze a squeezed sponge. Just like a zip of a zip is basically the same size (or greater) than the original zip, though obviously not a big as its original contents.

Get used to it: lossy coding is often 100x-300x smaller than their uncompressed equivalent, and 50x-100x smaller than a lossless equivalent. Stick with what you've got, re-compress to further lossy files (at further loss of quality), or get bigger storage.

Scott

[lingyi]

To continue what pdr said, most videos use lossy compression, which is many times smaller than lossless compression. And one of the things they use in their format - in addition to perceptual guessing, etc. - is some form of lossless coding.

Most all lossless coding takes the redundancy out of a file (usually by first re-ordering the numbering structure to put like #s in a sequence and then use a shorthand substitution). So if a file has already had it's redundancy removed, there is no more to remove. AKA no more compression to be gained, by further lossless coding. You can't further re-squeeze a squeezed sponge. Just like a zip of a zip is basically the same size (or greater) than the original zip, though obviously not a big as its original contents.

Get used to it: lossy coding is often 100x-300x smaller than their uncompressed equivalent, and 50x-100x smaller than a lossless equivalent. Stick with what you've got, re-compress to further lossy files (at further loss of quality), or get bigger storage.

Scott

To add to what Cornucopia stated above, a quote (from myself) in this thread https://forum.videohelp.com/threads/373692-Backup-Archiving-Video-Files?p=2406425#post2406425/

BTW, commercial DVDs and Blu-Rays are far from perfect sources for archiving. As pointed out in a recent interview with a video compressionist on AVSForum, the typical digital source for movies is ~2TB, meaning a Blu-Ray retains ~2% of the original data and a DVD is ~.02%. In addition, there is the reduction in color bit rate from 10-12bit color reduced to 8bit for current DVDs and Blu-Rays.

Here's the link to the AVSforum video / Podcast http://www.avsforum.com/forum/138-avs-forum-podcasts/2099754-all-about-video-compressi...mpression.html with lots of info about the "art" of being a compressionist / colorist.

[Cornucopia]

[Off-topic]
BTW, lingyi, filmmakers don't use their distributed DVD/Bluray copies as their archive (except in very extreme circumstances where something was lost due to fire, etc and that's all that was left).
They keep all multiple TB (2TB is probably the bare minimum for ~135min of 2k high-bitdepth 4:4:4 master footage, and if it were an HDR 4K master it would be min. ~14TB). And that's not counting all their referenced source footage (always kept) & working/intermediate footage (particularly compositing passes/layers), which most would keep (as long as it saved them more than a day or 2 of re-rendering). Then there's unreferenced footage (outtakes). Quite a lot, indeed.
[/Off-topc]

That's why I have to laugh (cry?) when I hear about somebody trying to squeeze an extra drop out to make a title fit a CD or something.

For the OP, downrezzing & lowered-bitrate lossy re-encoding can save you quite a bunch with a moderate loss in quality. But if you already really care about the quality, best to leave it as-is.

Scott

[lingyi]

[Off-topic]
BTW, lingyi, filmmakers don't use their distributed DVD/Bluray copies as their archive (except in very extreme circumstances where something was lost due to fire, etc and that's all that was left).
They keep all multiple TB (2TB is probably the bare minimum for ~135min of 2k high-bitdepth 4:4:4 master footage, and if it were an HDR 4K master it would be min. ~14TB). And that's not counting all their referenced source footage (always kept) & working/intermediate footage (particularly compositing passes/layers), which most would keep (as long as it saved them more than a day or 2 of re-rendering). Then there's unreferenced footage (outtakes). Quite a lot, indeed.
[/Off-topc]

That's why I have to laugh (cry?) when I hear about somebody trying to squeeze an extra drop out to make a title fit a CD or something.

Scott

Kismet! I'm re-listening to the AVSforum podcast and the coimpressionist David Mackenzie talked about how the masters used to be delivered on digital tape and how even the 2TB master is often slightly compressed. I envy and appreciate your first hand knowledge of the quality of a real master!.

I also get a chuckle when posters refer to their BD/DVDs as "archival quality masters". Having lived long enough to see the same movie on broadcast TV, videotape , CED (remember Needlevision? LOL), LD, DVD and now BD, I hope to be around to see some of my favorite films on the next generation media (4K, HDR?) and beyond.

[LigH.de]

This makes me chuckle on a different level ... I once worked in a DVD authoring studio, and I remember that the cinematic company received an HD film scanner which could work in real time but had to use a 10 HDD RAID (ten is the number of parallel harddisks) to store the digitalization fast enough.

Now, in times of UHD, I wonder if all those efforts are now pityfull...

[pandy]

I have found many things about lossless compression but no definitive answer to my question. Is there any true lossless compression where you compress a video and get the same video back out pixel for pixel and sound for sound with absolutely no loss of quality even if its not perceptible? I have 4 TB of storage on my laptop so saving the most amount of space is not that important. If I cut 20% off a 40GB movie I will be extremely happy.

And? Do you have access to uncompressed source? Is your notebook is capable to deliver sustained 80 - 290MBps?

[solarfox]

CED (remember Needlevision? LOL)

Remember it? I still have one!

[Wayneman101]

Thank you for your replies. They are copies of Bluray and DVD so they are compressed already. It is good to know about how all this works. Thanks for the help.

[KarMa]

Thank you for your replies. They are copies of Bluray and DVD so they are compressed already. It is good to know about how all this works. Thanks for the help.

Yeah you said 40GB which made me think it was a Bluray copy since that is a perfect size for a Bluray.

While you may not be able to losslessly compress the video, you could get rid of a duplicate versions of audio that may be present in the .TS or .M2TS. Often times there will be many different audio streams that are either surround 5.1 or stereo 2.0, using different codecs (AC3, TrueHD, DTS, DTS-HD MA, LPCM). So you may think of keeping one of the lossless audio sources and deleting the rest which can save some GiBs.

TrueHD, DTS-HD MA, and LPCM would be the lossless streams.