CPU for single h.264 50 mbit transcode (budget option)

server-linux

#1

Hey guys,

After tedious days of research and reading tons of forums and spreadsheets I still have no answer to what bothers me.
I'm currently building a small, inexpensive power efficient NAS unit to serve as a backup machine and media server. The difficulty is it has to be able to transcode my full blown bluray rips (1080p24 h.264 files with 40-50 mbit) in real time down to 6-10 mbit 1080p h264 as well as lower rosolutions for the client side while direct streaming up to 4K (latter should be not taxing at all). Don't have a plex pass for hardware-accelerated transcoding, not bying one. If I wanted hardware transcoding via Intel QuickSync I'd buy the overhyped PR4100 NAS. But I'm a sucker for quality and the PR4100 seems to use very low quality "superfast" preset for hw transcoding. Couldn't find any decent NAS capable of 1080p high bitrate software transcoding. On the PLEX support side it recommends a CPU with 4000 passmark score for single 1080p transcode, of 10 mbit source that is. However on the same site it states "Intel Core i5 3.0 GHz minimum". Doesn't state the generation though and a lot has changed in the past 2-3 years with Skylake and Kaby Lake architectures.

For my limited budget, will a Pentium G4560 with 4900 Passmark Score do the job of 1080p 50 mbit --> 10 mbit live transcoding?
Or is an i3 7300 (7100 passmark score) / i5 7500 (8100 passmark score) necessary for veryfast transcoding preset? Unfortunately I don't have the budget for double 36 core xeons / Core i9 or nor Threadripper. Idle consumption of the NAS has to be low but it must handle 1080p h264 50 mbit transcoding at the minimum. I'm really interested of what you guys are using for Plex Media Server transcoding and how it performs for you. Maybe AMD Ryzen APU is the way to go for Plex?


#2

@“alexander95@gmx.de” said:
If I wanted hardware transcoding via Intel QuickSync I’d buy the overhyped PR4100 NAS. But I’m a sucker for quality and the PR4100 seems to use very low quality “superfast” preset for hw transcoding. Couldn’t find any decent NAS capable of 1080p high bitrate software transcoding.

Any transcoding is going to be less quality than the original, so if you are a sucker for quality you should be direct streaming as much as possible anyway.

On the other hand, if you are transcoding for mobile and other less than home theatre serious watching, then who cares what preset is used as long as it can get the job done smoothly without lagging or buffering etc.

Also you mention direct streaming 4k, and well if something can do that, then it should be direct streaming your bluray rips also, negating any need for transcoding.


#3

Absolutely, as much as I’d love to be able to direct stream at 40-50 mbit on the go, neither my upload speed nor my family’s download speed allows for it. I want them to be able to stream my library in acceptable quality. The max my upload would do is 20 mbit, real world number is around 14 mbit. So 10 mbit stream is close to the max I will be able to uplink.


#4

If I may augment?

The KabyLake CPU and its GPU/ASIC provide some serious quality. in regard to hardware transcoding the video.

As stated, there is inherent loss in any transcoding. Hardware transcoding in the -6xxx (SDR-limited HEVC) , -7xxx and -8xxx (HDR) generation CPUs is outstanding IF you start with good material. Should you feed it 30+ Mbps rips, you’ll never see the quality loss. Should you feed it 10 Mbps re-encoded files, the hardware will amplify the defects and losses introduced when it was downsampled the first time (probably by HandBrake).

I personally rip and store all the bits. My rule of thumb: “The more you process it, the worse it will look so store the original.”


#5

Sounds nice but looks like I need an expensive plex pass for any type of hardware transcoding. Even the Plex mobile streaming app for android smartphones/tablets is extremely limited in the free version (1 minute watching) and costs 5 $ activation per account. Lifetime plex pass is like 150 $ I would be paying only to be able to use hardware transcoding. Don’t need all the other “benefits” the pass offers, not sure if I will stay with Plex in the future or use something else.
So I’m trying to avoid any additional software fees, the money is better invested in beefier hardware like faster CPU or more storage.


#6

The Plex Pass is $4.99 a month (USD) . When you buy a PlexPass , (I believe if you buy the app also), the 1 minute playback limit is removed

Also, with an active PlexPass, all the activations for the app are included. You don’t need to activate each installation of the App


#7

Yep, that’s 60 $ a year and 180 $ for 3 years. Tbh not a fan of subscriptions at all unless absolutely necessary… The cheapest option is to go with the lifetime plex pass license which is 120 $. Not too bad but still a lot of money just for enabling 1 feature I will use. I will think about getting this but it would hurt my tight budget pretty hard.


#8

How about this?

Get the first month and try it. Make sure it’s what you really expect. If not, it’s no worse than a bad app purchase at the Apple / Google app store. true?


#9

Plex is not perfect, and the lifetime plex pass is expensive no doubt.

If you are unsure whether the plex pass is worth it, 1 month for less than a lunch meal is hardly a difficult swallow to try out the features.

Not only the hardware transcoding, but simply the fact that 1 plex pass on your server allows for essentially free client access for your family/friends that connect to your server.

You can add family/friends with either their own plex account or as managed users without a dedicated account (they will be like sub-accounts of your plex account).

Of course if you absolutely want to avoid subscription or lifetime costs, you can pre-transcode your movies (via handbrake or similar) to direct streamable files of 5-10mbs bitrates so your clients can stream over the internet without any transcoding.

Keep your HQ bluray rips in one library for your local use, and keep your pre-transcoded copies in a separate folder and library for your streaming needs.

thus you avoid the cost of on the fly transcoding, cheaper/quieter lower power cpu needs, and no need for plex pass hardware transcoding.

Of course you will pay in extra disk space usage.

There are no free rides in the home media storage and streaming game.


#10

Soo gonna revive this thread from the dust. Got started with Synology DS918+ NAS and Plex Media Server. So far liking the interface and user experience especially on desktop. Had major hickups with library metadata but moving files to a new created library did the trick for me. Streaming out of home from app.plex.tv was a hard nut due to my ISP using ipv6 only via Dual Stack DS-Lite (external port mapping to ipv4 needed) and Plex Settings limitations but got it working eventually. Flawless playback both local and external streaming and software transcoding huge h.264 1080p files to any resolution and bitrate, acceptable loading times, working subtitles. At 100 % CPU usage for a single stream. that is. veryfast preset converting to 8 Mbit 1080p gets pretty decent streaming quality, 1080p @ 12 Mbit output is noticably better though. Nevertheless pretty impressed the tiny Intel Pentium J3455 can handle live SW transcoding 1080p h264 (bluray 1:1 stream) that well.
Gonna try the Plex Pass really soon and will sure run the numbers of max. hardware transcode streams possible at a time, both 4k 100 mbit camera footage and 1080p bluray copies.