Why does the HD-PVR use H.264 rather than MPEG-2

[wayner]

What is the main reason that the HD-PVR encodes files to H.264 rather than MPEG-2? I can think of one advantage, smaller file size, but that is becoming less of an issue with the price of 1TB hard drives approaching $100. And there would be lots of advantages to using MPEG-2 - many of the problems relating to the HD-PVR seem to stem to using H.264, not the least of which is problems with codecs and the hardware requirements for decoding H.264. And using MPEG-2 would have been much more similar to other HD file types in Sage, such as OTA, QAM, firewire, etc.

Is there some other reason for using H.264 such as being easier to do hardware encoding that I am missing?

[jerryt]

Smaller file size.

Yes, I agree MPEG 2 would have been nice.

[Brent]

The main reason it was done with h.264 in the HD-PVR is the cost of the board inside of the HD-PVR was affordable enough to use for this purpose. The innards of the HD-PVR are used in camcorder applications etc and therefore had the right price point.

[stanger89]

Yeah, that's really the big one. There was no HD MPEG-2 encoder ASIC that made it into production in the sort of high-volume applications necessary to make such a chip cheap. In contrast, H.264 (specifically AVCHD) has become the defacto standard for HD camcorders, meaning there's a huge volume for these chips, which in turn means the chips can be sold cheaply and picked up for other uses, like the HD PVR.

[dynamix]

shrug. hd-pvr is already pretty expensive anyway. I don't think a couple extra bucks would've made that big a deal.

In my opinion, the my HVR-1600 is an affordable card, records in MPEG-2, and is better quality than the files of the PVR-HD. Also uses less CPU. Also doesn't have a loud fan and bright blue light during recording.

Hauppage is really missing out if they don't combine the best features of the HVR-1600 and the PVR-HD... I can't deny the incredible usefulness of being able to record HD sources with the PVR-HD, but it should've been executed differently.

imho, the HVR-1600 is one of the best hauppage cards I've owned. I wish the PVR-HD included its features....

[Brent]

Originally Posted by dynamix

shrug. hd-pvr is already pretty expensive anyway. I don't think a couple extra bucks would've made that big a deal.

I'm no expert here, but do know a little about how the HD-PVR came into existence. And I can say with some certainty that we are not talking about a couple of extra bucks. The design of the HD-PVR was created around the ambarella chip inside of it because its cost was hundreds less then the next available board. You can find devices to do what the HD-PVR does with more flexibility if you look to the professional media companies, but it woud never have made it to the consumer level at those prices.

Honestly the ideal would be a CableCard-like tuner without the DRM so you have true digital coming in sans the DRM, but I kind of doubt we'll ever see that.
I'm very happy with my HD-PVR now. I'm using it to record many shows in HD, watching sports live in HD and now have comskip working to detect the commercials. The device is definitely not perfect though as we can see by how many people have had trouble with it thus far.

[Chriscic]

MPEG2 is the past, MPEG4 is the future anyway. Sure, there are problems now, but all that stuff will eventually get sorted out (in general, and hopefully specifically with the HD-PVR).

[wayner]

Originally Posted by Brent

Honestly the ideal would be a CableCard-like tuner without the DRM so you have true digital coming in sans the DRM, but I kind of doubt we'll ever see that. I'm very happy with my HD-PVR now. I'm using it to record many shows in HD, watching sports live in HD and now have comskip working to detect the commercials. The device is definitely not perfect though as we can see by how many people have had trouble with it thus far.

The problem with a CableCard-like tuner is that you can't get CableCards for all devices such as satellite tuners and here in Canada none of the cable companies will give their customers a CableCard. The beauty of the HD-PVR is that it uses an interface (component) that pretty much every HD device has and it does not require any special hardware/permission from your cable co/satellite co. It also doesn't require channels to be unencrypted. That has HUGE benefits.

The problem that I have with the device is that it is noisy, the h.264 file format is not that widely supported (correct me if I am wrong but this includes Sage Placeshifter) and it is a pain in the butt to get h.264 files playing smoothly on many PCs, particularly if your CPU is more than a couple of years old. It is so much easier to use HD files that come from my OTA tuner rather than the HD-PVR. It would be nice to be able to use the HD-PVR to tune all of your channels but I am coming to the conclusion that I am better off using an analog tuner for SD channels, an OTA tuner for OTA HD and limit the HD-PVR to only tuning cable-only HD channels.

But I absolutely love the fact that I can get all HD channels into my PC. The only problem is that I feel like I am on the bleeding edge right now, even though I haven't had any major issues with my HD-PVR like lockups, etc.

[wayner]

Originally Posted by Chriscic

MPEG2 is the past, MPEG4 is the future anyway. Sure, there are problems now, but all that stuff will eventually get sorted out (in general, and hopefully specifically with the HD-PVR).

But what is the downside to MPEG-2? It will be with us for a long time to come as cable companies are not switching away from it that quickly and regular old DVDs are not yet disappearing. I don't mind a larger file size, which is the primary disadvantage of MPEG-2, with hard drives costing about $120/TeraByte given the advantage mentioned above.

[chrisc16]

Originally Posted by dynamix

In my opinion, the my HVR-1600 is an affordable card, records in MPEG-2, and is better quality than the files of the PVR-HD. Also uses less CPU.

The HVR-1600 only records in MPEG-2 because that's the signal that it's receiving. And it uses less CPU, sure, because all it's doing is writing the (already compressed) ATSC or QAM streams to disk.

The HD-PVR takes an analog signal and compresses it to MPEG-4. It's doing something totally different than the HVR-1600, so it's not fair to compare the two.

-Chris

[chrisc16]

Originally Posted by wayner

But what is the downside to MPEG-2?

Cost. If there was an affordable (<$500) chip that could compress HD analog signals to MPEG-2, I think there would be several companies selling products based on it.

-Chris

[lobosrul]

Originally Posted by wayner

But what is the downside to MPEG-2? It will be with us for a long time to come as cable companies are not switching away from it that quickly and regular old DVDs are not yet disappearing. I don't mind a larger file size, which is the primary disadvantage of MPEG-2, with hard drives costing about $120/TeraByte given the advantage mentioned above.

Yes but those drives are essentially no faster than older drives. If I use a single recording drive, I can't even sustain 2 HD (19Mbps) recordings, 2 clients playingback, and 2 instances of Showanalyzer at the same time. I get stuttering. Enter the HD-PVR and 5 to 8 Mbps recordings and I bet I would have no problem.

[brandypuff]

Originally Posted by chrisc16

The HVR-1600 only records in MPEG-2 because that's the signal that it's receiving. And it uses less CPU, sure, because all it's doing is writing the (already compressed) ATSC or QAM streams to disk.
-Chris

I bought one of these cards for $60 earlier this year and it's the main reason I purchased SageTV and the HD-1000. The card is great and works flawlessly with SageTV.

[dvd_maniac]

I would have already bought 2 or 3 of these if they recorded in Mpeg-2, even with all the problems they have been having.
I understand that AVC is the future but I wish there was a way to easily edit these files in the present. I was torn between this and the HDHR but now that I have an HDHR and I only receive 7 unencrypted QAM channels from Charter cable, I think I'm getting forced to buy one of these.

Anybody that owns one of these... If I record from a Premium channel, can I easily edit out the beginning and end of the file without re-encoding?
How low of a bitrate can be used to simulate DVD quality for permanent archiving?

[Sam]

Originally Posted by dvd_maniac

Anybody that owns one of these... If I record from a Premium channel, can I easily edit out the beginning and end of the file without re-encoding? How low of a bitrate can be used to simulate DVD quality for permanent archiving?

When I first got my HDHR, I could get lots of channels which my local Comcast region has since encrypted. I still like the HDHR, but ended up with a HD-PVR too in order to get more channels. I will probably get a second HD-PVR soon.

There are a few utilities out there which purport to do what you ask, such as TSCutter, but I have not had success with them and HD-PVR recordings. I am hoping VideoRedo gets H.264 support working, but I haven't heard a projected availability date. (It is what I use for mpeg-2 editing.)

In the meantime, what I'd suggest is getting DVRMSToolbox from babgvant.com -- he has worked out methods for transcoding the *.ts files to *.mpg in a very efficient manner. And it has an incredibly powerful file watcher and action editor.

Using it, you can have all your HD-PVR files transcoded to mpeg-2 concurrent with the recording. This gives the near equivalent to what you want; a HD-PVR with mpeg-2 output. It just requires some CPU on your server.

What I'd suggest is having the HD-PVR output at the max 13.5Mbps rate, so you have the highest quality input to the mpeg conversion, then output whatever mpeg rate you want for your archives.

On my quad-core, it will convert a 6GB hour long recording (at 13.5Mbps) to a DVD quality (6300Kbps) mpg file in under 20 minutes, but I am allowing it to use all the cores and don't limit the priority. There are lots of throttling options. I am guessing it would take under 33% of my cpu to do it in real-time as the show was being recorded.

Then you could just delete the *.ts and edit the *.mpg using whichever tool(s) you want to trim padding and commercials.

Eventually, I suspect people like VideoRedo will work out how to add H.264 support directly. In the meantime, DVRMSToolbox can get you the mpg output in real time.

[dvd_maniac]

In the meantime, what I'd suggest is getting DVRMSToolbox from babgvant.com -- he has worked out methods for transcoding the *.ts files to *.mpg in a very efficient manner.

That sounds interesting. You use this method with 100% success?
I wouldn't mind a minimal loss in quality to .mpg but then another loss encoding back to X264? It seems like it is worth a try though. You are sure a one hour video transcoded from HD-PVR to Mpeg-2 only takes about 20 minutes on your quad-core?
I have a Quad-Core as well so I think I'm going to order one HD-PVR tonight and test it out before replacing all my analog tuners.

[wayner]

Originally Posted by dvd_maniac

I have a Quad-Core as well so I think I'm going to order one HD-PVR tonight and test it out before replacing all my analog tuners.

If you do any recording of SD analog channels then I would not suggest getting rid of analog tuners. It is so much easier to use clients, video editors, placeshifter, etc. with MPEG-2 files rather than h.264.

[dvd_maniac]

If the process mentioned by Sam to transcode to mpeg-2 is that quick then I will automate the process using Dirmon on all my recordings to Mpeg-2.
This will take away all the issues you mentioned in your post.
Plus I will have better quality recordings...

[Sam]

Originally Posted by dvd_maniac

That sounds interesting. You use this method with 100% success?

It has been 100% bullet-proof. I should point out I don't have it transcoding in real time, but I see no reason it couldn't. I have used it lots of times to convert a HD-PVR recording to DVD quality mpg2, then VideoRedo TV Suite to trim, edit, and burn to DVD.

And yes, I am sure that it takes about (just under) 20 minutes per hour of recording. I record at 13.5Mbps then have it convert to 6.3Mbps mpg2 for burning to DVD. My quad-core is a Q6700, but isn't overclocked.

I wouldn't mind a minimal loss in quality to .mpg but then another loss encoding back to X264?

I don't convert back to x264. Disk is too cheap.

I have a Quad-Core as well so I think I'm going to order one HD-PVR tonight and test it out before replacing all my analog tuners.

I'd keep your analog tuners (or switch to hybrids like the 2250). Let them do the mpeg encoding so you don't need CPU cycles for that. Use a HDHR or hybrid tuners to get the clear QAM or OTA channels available in HD. That means you only a STB and HD-PVR combo for the remaining channels. It makes it much easier to get by on a single STB rental and HD-PVR.

I never really thought about just having all my HD-PVR recordings convert to mpeg2 as they record, until writing the previous post. DVRMSToolbox has a profile designed to convert to a smaller format for the sake of commercial detection (smaller just so it takes less overhead). It can run concurrent with the airing, so I see no reason a conversion to full size DVD quality mpg2 should not as well (with higher CPU demand).

Maybe I'll experiment with it, and let ComSkip run against the conversion too.

[wayner]

Originally Posted by Sam

Maybe I'll experiment with it, and let ComSkip run against the conversion too.

If you get a chance can you please let us know how it goes Sam?