2xRealtime encoding

[simmonsjeffreya]

Hi,
I'm looking to build a new system that can do 2 times Realtime (Or Better) encoding of x264 720p MKV files. I know this can be done, but can't for the life of me figure out how.

I'm looking to build a new system since I just got another TiVo HD XL and am wanting to backup Everything from it, encode, then put it back on. I know how to do the pull/push, but the encoding is where I'm at a loss. Right now it's taking me about 4-6 hours to encode each 1 hour show.

Since I record up to 15 hours of TV a day, this is obviously a huge problem and is leaving me weeks behind in encoding to save space. If anyone has a system capable of this, or has any idea fo what kind of hardware would be required to do this, I would greatly appreciate it.

Also I've been searching but have come up with almost nothing, but is there any Hardware x264 encoder? I found that Leadtek Cell SpursEngine thing, but it looks as though you have to use their custom encoding software which I'm hearing mixed things about. Again any input is greatly appreciated.

Thanks,
Jeff

[cogman]

What is your target budget, and what tradeoffs are you willing to make?

Most systems can do the 2x realtime encoding with x264 if you just use --preset ultrafast, but obviously, you lose quality at a given bitrate or increase the bitrate. (using crf can minimize/eliminate this at the cost of a higher bitrate). No system that I know of can do --preset placebo at 2x realtime.

The cheap solution is to go through all the presets, ( http://mewiki.project357.com/wiki/X264_Settings ) and see which one is able to do 2x realtime for you. If that setting is unacceptable, the consider a new system.

The CPUs that works the fastest with x264 to date are the core i7 or i5's.

[DJ Bobo]

I'd say 2x realtime is impossible on a consumer PC. You'll probably need a multi-socket server motherboard to achieve this.

Anyway, there is a small piece of hardware by Hauppauge which goes by the name of "HD PVR (http://www.hauppauge.com/site/products/data_hdpvr.html)" (or WinTV HD PVR).
It can capture 720p content and encode it on-the-fly to H.264. You can push up the bitrate up to 13Mbit/s VBR, which is almost overkill for 720p! So quality will be excellent, you don't have to worry about this!
You just connect your receiver through component cables to the box and let it do the rest.
It can even record Dolby Digital sound through its optical input (else it would record your analog sound to Stereo AAC).
Very nice piece of hardware indeed!

[Shinigami-Sama]

I'd say 2x realtime is impossible on a consumer PC. You'll probably need a multi-socket server motherboard to achieve this.

...x264 can do 2x realtime on an i7 just fine...

[DJ Bobo]

...x264 can do 2x realtime on an i7 just fine...

I seriously doubt that my friend.
According to the 720p benchmark hosted by TechArp, you get 33fps with the 3,33GHz Core i7, and this is not including any capture overhead.
2x realtime for TV shows means 100fps or 120fps... you get the idea ;)

[RunningSkittle]

I seriously doubt that my friend...

--preset ultrafast
;)

[Shinigami-Sama]

I seriously doubt that my friend.
According to the 720p benchmark hosted by TechArp, you get 33fps with the 3,33GHz Core i7, and this is not including any capture overhead.
2x realtime for TV shows means 100fps or 120fps... you get the idea ;)

you trust people that use an ancient build to do benchmarks with?
lololololol

[DJ Bobo]

@ RunningSkittle
Wouldn't that defeat the purpose behind AVC compression? Efficiency would be very low, so that it probably makes more sense to use a DivX HD profile instead, no?
Still not sure that a single CPU configuration could reach 120fps with that preset.

@ Shinigami
Well, they updated their benchmark with the latest x264 version, I didn't see any significant speed improvement, you?

[Shinigami-Sama]

@ RunningSkittle
Wouldn't that defeat the purpose behind AVC compression? Efficiency would be very low, so that it probably makes more sense to use a DivX HD profile instead, no?
Still not sure that a single CPU configuration could reach 120fps with that preset.

@ Shinigami
Well, they updated their benchmark with the latest x264 version, I didn't see any significant speed improvement, you?

I've seen 120fps speeds before...
and ultrafast still beats divx...

[DJ Bobo]

Well, I've done a small test with ultrafast, and I must admit, I didn't expect the speed rise to be this big: 6x! I wasn't expecting something beyond 2 or 3x.
So yeah, 120fps may be reachable on very high end consumer configurations.
So, if bitrate isn't a big issue, ultrafast would be a viable choice indeed, I stand corrected.

Still, the HD PVR box is probably the better alternative since he's capturing all the time. Would save him the hassle of re-encoding and quality should be better than x264 on ultrafast.
Would also save him a lot of money, the box is cheaper than the slowest Core i7 processor by itself.

[mariush]

You could give Winfast PxVC1100 a try, it's supposed to do hardware encoding to mpeg2 and mpeg4 pretty fast (it uses SpursEngine - a lighter and cheaper PS3 Cell processor):

http://www.leadtek.com/eng/tv_tuner/overview.asp?lineid=6&pronameid=505

though this thread doesn't make it look so good http://forum.doom9.org/archive/index.php/t-141070.html

DJ Bobo, that HD PVR thingie doesn't accept hdmi, it takes composite signal or s-video or whatever and most likely uses something a bit more complex than x264's ultrafast setting. read the card reviews on newegg to get a clue about the quality.

[simmonsjeffreya]

As for encoding profiles, my target is to just be able to use the MeGUI x264_dp_ Unrestricted 2pass HQ profile, if possible. My budget is about $2500 for CPU(s)/Mobo/RAM and any PCIEx cards that may be beneficial. I already have the rest of the hardware sitting around. Obviously the less spent the better, $2500 is as high as I can go though.

You could give Winfast PxVC1100 a try, it's supposed to do hardware encoding to mpeg2 and mpeg4 pretty fast (it uses SpursEngine - a lighter and cheaper PS3 Cell processor):

http://www.leadtek.com/eng/tv_tuner/overview.asp?lineid=6&pronameid=505

though this thread doesn't make it look so good http://forum.doom9.org/archive/index.php/t-141070.html

DJ Bobo, that HD PVR thingie doesn't accept hdmi, it takes composite signal or s-video or whatever and most likely uses something a bit more complex than x264's ultrafast setting. read the card reviews on newegg to get a clue about the quality.

That's the card I was talking about in my original post. While it looked promising the downsides were just too many for the price unfortunately, unless things have changed recently.

[DJ Bobo]

@ mariush
The composite and s-video connectors of the HD PVR are for SD only.
For HD, you have to use the component connectors behind, which are suitable for 720p and 1080i. Component video is of very high quality!
The reviews I read certify very good encoding quality (the box has a 4 stars score on newegg anyway, the majority of the reviewers are very satisfied with the box).

@ simmonsjeffreya
Well, the HD PVR box costs less than a tenth of what you're willing to spend, and will surely make your life easier :)

[RunningSkittle]

DJ Bobo: what did you think "ultrafast" meant :cool:

[DJ Bobo]

@ RunningSkittle
Well, living in a marketing world as we are, it's difficult to believe fancy words like "ultra" and "hyper" :devil:
Sometimes, too much experience can fire back at oneself :D
Seems like the people behind x264 are honest after all :D

[Shinigami-Sama]

Well, I've done a small test with ultrafast, and I must admit, I didn't expect the speed rise to be this big: 6x! I wasn't expecting something beyond 2 or 3x.
So yeah, 120fps may be reachable on very high end consumer configurations.
So, if bitrate isn't a big issue, ultrafast would be a viable choice indeed, I stand corrected.

Still, the HD PVR box is probably the better alternative since he's capturing all the time. Would save him the hassle of re-encoding and quality should be better than x264 on ultrafast.
Would also save him a lot of money, the box is cheaper than the slowest Core i7 processor by itself.
decoding input can become a bottle neck on ultrafast ;)

and I also really doubt that any blackbox in consumer land is going to beat x264, unless its using ~2-3x the bitrate; even then...

[DJ Bobo]

and I also really doubt that any blackbox in consumer land is going to beat x264, unless its using ~2-3x the bitrate; even then...

It seems like you got on the ultra train :D
It will sure beat x264 on ultrafast, don't worry, I mean, ultrafast has absolutely no options enabled, it's almost like going back to good old DivX 3.11 ;-) (Where did that smiley come from? :D)
x264 with HQ options plays in another league of course ;)
Let's say that ultrafast needs about 2x as much bitrate as 2-pass HQ, and that our "consumer black box" will be somewhere inbetween (it uses VBR and Cabac after all, can't be that bad!). Anything beyond that would be "ultra-unrealistic" :p

[WillKane]

Capture box is still encoding at realtime, not two times realtime.