I have a collection of about ~110 4K Blu-Ray movies that I’ve ripped and I want to take the time to compress and store them for use on a future Jellyfin server.
I know some very basics about ffmpeg and general codec information, but I have a very specific set of goals in mind I’m hoping someone could point me in the right direction with:
- Smaller file size (obviously)
- Image quality good enough that I cannot spot the difference, even on a high-end TV or projector
- Preserved audio
- Preserved HDR metadata
In a perfect world, I would love to be able to convert the proprietary HDR into an open standard, and the Dolby Atmos audio into an open standard, but a good compromise is this.
Assuming that I have the hardware necessary to do the initial encoding, and my server will be powerful enough for transcoding in that format, any tips or pointers?
Just FYI, despite what media companies would like you to believe, making copies of media you own for your own use is not piracy. It’s allowed by law under fair use.
Mhm, I’m aware. I just figured the nice folks here would likely have more experience with codecs and such than elsewhere!
(That, and, if I can build my own replacement Disney+, I would definitely want to share with friends.)
You’re about to embark on a massive journey and I wish you the best of luck :D
Compressing 110 4K movies is going to be a long encode time, but it will be so nice to digitize that collection.
First question: if you already have them ripped and stored, do you even need to re-encode them? If you have a powerful enough Jellyfin server for transcoding, that may be enough.
That said, if you’re looking to optimize for space and quality, there’s some questions to ask:
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proprietary (but ubiquitous) HEVC or the emerging open standard AV1? It’s going to be a lot easier finding tips/guides for HEVC.
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Constant Rate Factor (CRF), or Average Bit Rate (ABR). CRF tends to be more straightforward if you have a varied collection of content because it let’s the encoder choose settings to deliver consistent quality. 2-pass average bit rate is good if you have a target size or compatibility in mind - great for squeezing out the absolute optimal quality if you’re trying to fit on a Blu-Ray disc or meet certain streaming criteria, but 2x the encode time (hence “2-pass”) can be a tough sell.
Stick with software encoding, steer clear of hardware solutions like NVENC. They’re crazy fast, but inconsistent quality.
There’s some guides out there on converting DV to HDR 10+ etc, but I don’t have a lot of experience with that process.
The issue is storage costs. Currently they (and some Blu-ray shows I ripped) are taking up just over 12TB. I bought all of these movies when I had money to spend on stuff like that, but money is short and times are tough. “Storage is cheap” but my wallet is cheaper right now, aha.
Look, I definitely get it, but just a note, encoding 100+ 4k HEVC movies is going to take months of time at full PC loads. It’s a subtle cost, but depending on your electricity rate, running a 200W PC 24/7 for 3 months straight may hurt your bottom line more than it helps.
If you already have the storage, the cheapest option may be just to keep it. If you’re looking to increase the size of your collection it may be about even to save 6 TB via encode and to buy an extra 6TB disc, depending on your setup
I did a comparison trying to find where my personal “good enough” and techinically indistinguishable crf levels were at a little while ago. It may be worth looking into as a start. I’ve never really touched hdr before though.
oh hey I’ve actually done this recently so a lot of this is fresh for me. Now I had a slightly different use case than you, I had a bunch of AV1 files that wouldn’t run on my pi so I had to convert them to something less GPU intensive. I was finding x265 was indistinguishable for me from AV1, and had a HUGE file size drop, close to a half or even a third. x264 had a larger file size than 265 and looked worse so I don’t recommend it. I did not try VP9 once I was satisfied with 265 but you could try it out and see how it compares. My recommendation is to pick one (shorter) file and run a couple of different transforms on it till you’re satisfied before trying to transform your entire library
Preserving audio and metadata is trivial, just use -c:a copy for audio and -c:d copy for metadata
EDIT: I feel dishonest not mentioning the important caveats regarding my own experiments. My files were 1080p, so the difference between codecs might be less noticeable at that resolution. It was also anime, which is similarly going to be easier to compress and be less distinct between codecs. This is why I cannot recommend x264 because if you can ruin 1080p anime it’ll ruin whatever you’re working with. This is why I recommend picking a sample video and spend a day running a couple test transformations on it to see what you like
Skipping the audio encode from a blu-ray will lose op out on a surprisingly large amount of space, especially with 110 source disks. I checked one of my two hour blu-ray backups. Audio will net you about nine audio tracks (english, french, etc). A single 5.1 448kbs audio track will take about 380MB of space per movie. Multiply that by nine (the number of different tracks in my sample choice) and you’ll get 3420MB per disk. That means about 376GB of space is used on audio alone for ops collection. A third of a terabyte. You can save a lot of space by cutting out the languages you don’t need, and also by compressing that source audio to ogg or similar.
By running the following ffmpeg command;
ffmpeg -i out-audio.ac3 -codec:a libvorbis -qscale:a 3 small-audio.ogv
I got my 382MB source audio track down to 200MB. Combine that with only keeping the language you need, and you end up dropping from 376GB down to 22GB total.
You can likely save even more space by skimping on subtitles. They’re stored as images, so they take up a chunk of space too.
Since you’re talking about anime, how did you solve the subtitles problem? My pi doesn’t transcode fast enough but I haven’t found a tdarr extension to do that automatically (nor a command)
