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Why Blu-Ray is better than HD-DVD.

1992 Views 26 Replies 11 Participants Last post by  dt_dc, 
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First of all, let me state that I am making this bold claim based on the facts as I understand them. I am not a "format fanboy", simply interested in seeing the "best" technology come into play.


Second of all, let me also state that I am not interested in "demanding" that consumers buy one product or another. Once again, I am not a "format fanboy". If I have made critical errors in my analysis, let me know, and I will either correct my mistakes, or request for this post to be deleted.


Here, in my humble eyes, is why Blu-Ray is a better high definition disc based format over HD-DVD;


The ATSC format, which includes high definition material, uses the MPEG2 compression scheme. This means your current HD tuners receive a compressed video stream, decodes the signal, and then streams the video to your display.


While ATSC is still in its "infant" stage (even though it has been around in committee since the 80s, maybe earlier?) it is doubtful, at least for a number of more years, the compression scheme will be changed.


So how does this tell me why HD-DVD is "inferior" to the Blu-Ray format?


One word: re-encoding.


That's right. Let's say the HD-DVD format wins over consumer's heart. (let's face it, home theater enthusiasts are a minority) HD-DVD uses a variation of the MPEG4 compression scheme.


Why is this bad?


Any time you take an encoded/compressed file, decode it, and alter it by compressing it even further, no matter the compression scheme, there is always the chance for degradation of the original signal.


Ever taken a previously compressed video file, say using the MPEG2 scheme, and compressed it even further, say using the MPEG4 scheme? To achieve high-quality results, it either requires decoding and encoding hardware, OR, tremendous processing power and multiple passes to achieve decent-quality software re-encoding and deeper compression.


So back to the original point. HD-DVD has won the format wars, and is now the "accepted" king of media. HD-DVD recordable units eventually come out. Either the units will be expensive, requiring decoding and encoding hardware, or use a software path, take extra time to re-encode and apply the additional compression via multiple passes.


Do you want to lose quality of recorded memories? Remember, current HD consumer video cameras use the MPEG2 scheme to fit sixty minutes of video on a standard Mini-DV tape. HD STBs and built-in tuners use the MPEG2 scheme. D-VHS uses the MPEG2 scheme. Blu-Ray uses the MPEG2 scheme, meaning a 1:1 copy. What you record gets imprinted on the recordable media, no additional compression, no re-encoding.


So ask yourself which HD disc format you want, a format that uses the current HD codec, and will work best for recordable media, or a format that uses a "better" codec, but at the same time is a codec outside of the current realm of HD format?


I know which one I'll be voting for with my money at the register...


Mr Zoid
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Of course this is less of an issue in Europe - where it is likely that MPEG4 will be used for the new HD systems due to launch late this year and early next. Both HD-DVD and BluRay are likely to support MPEG4 recording. Of course the chances of any European STB outputting MPEG4 data is pretty much zero - it looks like some boxes will only have HDMI (not even analogue component) outputs...


AIUI one BluRay win over HD-DVD is that the BluRay camp have produced a 3 layer sandwich, which allows a single 25Gb BluRay layer and 2 DVD5 layers, to give you a 25Gb BluRay AND a DVD9 DVD on one disc.


The little issue with the much touted HD-DVD+DVD hybrid is that it only has a single DVD5 layer, not a dual layer DVD9. Think this may be because it needs a dual layer HD-DVD to get above the 15Gb single-layer HD-DVD limit? (Which won't be enough for a full-length decent quality film?)


I wonder if there will be clever discs in either format that only use the HD layers for the movie, and use th SD DVD layers for extras in both formats?
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Quote:
Originally posted by sneals2000
Of course this is less of an issue in Europe - where it is likely that MPEG4 will be used for the new HD systems due to launch late this year and early next. Both HD-DVD and BluRay are likely to support MPEG4 recording. Of course the chances of any European STB outputting MPEG4 data is pretty much zero - it looks like some boxes will only have HDMI (not even analogue component) outputs...
I think I had seen evidence the Blu-Ray spec could support the MPEG4 codec, which if is true, just makes even more sense to rally around BD-Rom.

Quote:
The little issue with the much touted HD-DVD+DVD hybrid is that it only has a single DVD5 layer, not a dual layer DVD9. Think this may be because it needs a dual layer HD-DVD to get above the 15Gb single-layer HD-DVD limit? (Which won't be enough for a full-length decent quality film?)
IIRC, 15 GB per side, or is it per layer? With MPEG4 compression, yes, it is enough for a full length movie. Of course, then you start running into movies like LotR, which pushes the envelop of DVD capacity as is.


Mr Zoid
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I beleive the HD-DVD group has said they will support recording and playback of MPEG2, MPEG4, and VC-1.


Yes, pre-recorded discs are planned to be MPEG4. But they're not going to take a compressed MPEG2 stream and re-encode it for recording ... it'll be recorded as MPEG2.


Their CES demo was of simultanious playback of an MPEG4 movie with an MPEG2 director's commentary.


Blu-Ray had originally said MPEG2 only ... but there's no reason they couldn't support multiple formats as well (and quite frankly, they probably will).


One other comment ... I thought most digital camcorders used DV compression. At least, mine does. DV isn't just a tape format ... it's also a compression method. The DVD camcorders use MPEG2 ... but the DV camcorders use DV. So you're going to "lose quality of recorded memories" no matter which way you go.
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I think that whichever format puts a high-quality series of players and content on the market first will probably win. In other threads it appears Toshiba will be selling an HD-DVD player this year and Warner Bros will be providing 58 titles in HD-DVD by the end of the year. That will give them a big boost.


I have absolutely no idea which is better technically. And it may not matter. (VHS vs. Beta).


Rich N.
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Quote:
Originally posted by MrZoid
I think I had seen evidence the Blu-Ray spec could support the MPEG4 codec, which if is true, just makes even more sense to rally around BD-Rom.




IIRC, 15 GB per side, or is it per layer? With MPEG4 compression, yes, it is enough for a full length movie. Of course, then you start running into movies like LotR, which pushes the envelop of DVD capacity as is.


Mr Zoid
Yep - BluRay is going to support MPEG4 AIUI. My point was that the lack of recordable MPEG2 HD on HD-DVD would be less of an issue in Europe - because there won't be MPEG2 HD to record!


Both BluRay and HD-DVD are likely to offer MPEG4 recording - so they compete more equally over here (whereas in the US BluRay could offer HD MPEG2 recording which it is possible that HD-DVD won't - so BluRay has the advantage)


As I said - kind of a moot point anyway - as I doubt we'll be able to get MPEG4 HD out of our sealed set top boxes anyway.


Not sure of the HD-DVD BluRay side vs layers stuff - but I think BluRay hybrid DVD+BluRay may be more of a winner than the HD-DVD+DVD hybrid.


I guess it is still far too early to tell. Major factors like software availability, cost of discs and players, as well as picture quality will obviously have a big part to play.


Also worth factoring in that PlayStation 3 is likely to be BluRay based.
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Quote:
Originally posted by dt_dc
I beleive the HD-DVD group has said they will support recording and playback of MPEG2, MPEG4, and VC-1.


Yes, pre-recorded discs are planned to be MPEG4. But they're not going to take a compressed MPEG2 stream and re-encode it for recording ... it'll be recorded as MPEG2.


Nope - but for a home recording solution they presumably will have to once HD-DVD recorders appear.


In Japan BluRay is already used as a lossless HD MPEG2 timeshifting recorder, with an internal BS satellite tuner in their BluRay recorders I believe?


If a US BluRay recorder had a firewire in and out, it would offer the same quality as D-VHS potentially, i.e. lossless.


The comparison was more for domestic recording rather than pre-recording I suspect. For pre-recorded material HD or film scan masters will presumably be used.


Quote:


Their CES demo was of simultanious playback of an MPEG4 movie with an MPEG2 director's commentary.


Blu-Ray had originally said MPEG2 only ... but there's no reason they couldn't support multiple formats as well (and quite frankly, they probably will).
Think the first generation BluRay recorders on sale now are MPEG2 only. The second generation BluRay devices, which will include players, which is what we are waiting for (with pre-recorded material), will be MPEG4 (and possibly VC-1) compatible as well.


AIUI MPEG4 is DEFINITELY part of the spec for BluRay players due next year.


Quote:
One other comment ... I thought most digital camcorders used DV compression. At least, mine does. DV isn't just a tape format ... it's also a compression method. The DVD camcorders use MPEG2 ... but the DV camcorders use DV. So you're going to "lose quality of recorded memories" no matter which way you go.
MiniDV camcorders use the DV codec. However they record a frame at a time (to allow frame accurate editing etc.) - so use less compression as they can't use motion redundancy. AIUI the DV codec runs at 25Mbs ish. In the US it uses 4:1:1 video, in Europe it uses 4:2:0 at miniDV levels.


Sure if you compress DV to MPEG2 you are moving from one compression scheme to another and there is a possible quality loss. However it may not be that great, as you can exploit temporal redundancy to deliver a higher picture quality for a given data rate. 9Mbs MPEG2 may well outperform 18Mbs DV for example?


HDV uses DV tape, and the DV tape format, but instead of using the DV codec it uses MPEG2. It uses the temporal redundancy of MPEG2 to squeeze a 1440x1080 MPEG2 video signal into the same space as a 720x480 DV one - but loses the discrete frame advantage of DV. It means HDV has to be edited on a non-linear system in reality, rather than tape-to-tape, which is possible with DV.


(HDV could potentially also offer tape to tape, but would need to MPEG2 decode and recode, which Beta SX sort of does, around the edit points, dropping the quality a bit)
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Quote:
Originally posted by dt_dc
One other comment ... I thought most digital camcorders used DV compression. At least, mine does. DV isn't just a tape format ... it's also a compression method. The DVD camcorders use MPEG2 ... but the DV camcorders use DV. So you're going to "lose quality of recorded memories" no matter which way you go.
Actually, IIRC, most digital video cameras are uncompressed. At least the standard definition variety. The compression scheme is up to you thereafter.


What I was refering to though is HD video cameras, like the JVC and Sony. They use MPEG2 to fit 60 minutes on one MiniDV cassette.


Mr Zoid
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Quote:
Originally posted by sneals2000
HDV uses DV tape, and the DV tape format, but instead of using the DV codec it uses MPEG2.
Yes ... I tend to forget about HDV (which was what the OP was referring to). By the time I actually buy an HD camcorder ... :)
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Quote:
Originally posted by MrZoid
Actually, IIRC, most digital video cameras are uncompressed. At least the standard definition variety. The compression scheme is up to you thereafter.
DV is compressed ... it's just a single-frame compression (unlike MPEG) so it's just not compressed much:
http://www.dvformat.com/htm/features...format_faq.htm
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Quote:
Originally posted by sneals2000
As I said - kind of a moot point anyway - as I doubt we'll be able to get MPEG4 HD out of our sealed set top boxes anyway.
Don't forget about the FCC firewire mandate. All HD STB's as of July of this year have to have functional firewire ports. They have been availible per request since April of last year.


No one expects this to go away. But the stream is protected by 5C so it's not like it is a free for all.
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Quote:
Originally posted by dt_dc
DV is compressed ... it's just a single-frame compression (unlike MPEG) so it's just not compressed much:
http://www.dvformat.com/htm/features...format_faq.htm
Thanks for the compression, er, correction. :D


Mr Zoid


It's been so long since I've really messed around with a DV cam...
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Quote:
Originally posted by bdraw
Don't forget about the FCC firewire mandate. All HD STB's as of July of this year have to have functional firewire ports. They have been availible per request since April of last year.


No one expects this to go away. But the stream is protected by 5C so it's not like it is a free for all.
Err... that's sort of true. Not to get sidetracked, but that's why I dumped a local cableco last year. I figure in reality they did have the required waiver, but they would not provide proof of said waiver, so I said so long suckers!


Moral of the story? If they're small enough, and get a waiver, they are not required to be carried by the cableco.


The first box I got from Comcast was a Motorola 6200 and had the firewire out enabled.


The 6412 I have now, I have not tested the firewire out, but I have been informated it is active.


Mr Zoid
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Everything I'm reading says that HD-DVD and Blu-Ray will support MPEG2, H.264 (MPEG4p10), and VC-1 ... with mandatory support from stand-alone players.


Although ... with the VC-1 delay it will be interesting to see how that plays out ...

http://news.yahoo.com/news?tmpl=stor...pcworld/119665
http://www.pcmag.com/article2/0,1759,1750098,00.asp
http://www.widescreenreview.com/attractions/yht2.html
http://www.commsdesign.com/design_ce...cleID=54800092
http://www.hdtvexpert.com/pages/hidefdvd.htm
http://www.iapplianceweb.com/story/O...114I0001BC.htm
http://www.mrgco.com/investorscorner...ebruary%202005


However, I think the OP's point about checking / thinking about codecs before running out to buy a next-gen DVD player is a good one. I certainly wouldn't want a player that didn't support MPEG2, if for no other reason than OTA ATSC playback (from a future recorder).
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Quote:
Originally posted by sneals2000
Of course this is less of an issue in Europe - where it is likely that MPEG4 will be used for the new HD systems due to launch late this year and early next.
Who were the brainiacs who locked us into MPEG-2?


I wonder what the North American broadcasters are going to think when they realize that they could have pumped an HD channel and 3-4 SD channels with BETTER quality than a single HD MPEG-2 channel, in their 6MHz band?


Instead, they will have to put up with screams from consumers to steal an SD channel (or two!) from the HD stream.


(sigh) F1 racing broadcast in 12 Mbps MPEG-4.


The conversions of European HD shows for NA broadcast are going to be gruesome.


Gary


P.S. I believe MPEG-2 is supported within MPEG-4. So MPEG-4 means MPEG-2 support.
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Originally posted by dialog_gvf
Who were the brainiacs who locked us into MPEG-2?
http://www.atsc.org/
http://www.fcc.gov/


They had to lock down something ... and MPEG2 was the best there was back then. H.264 is barely completed ... VC-1 still isn't ...


How many people were willing to buy those first $1k+ HD STBs? Not many ... How many would have been willing to buy them without some sort of finalization of standards? "This box could be obsolete the minute a better codec comes out ... but hey, plunk down $1k ... the picture looks good."


They had to standardize on something to get the transition going ...
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Quote:
Originally posted by dialog_gvf
Who were the brainiacs who locked us into MPEG-2?


I wonder what the North American broadcasters are going to think when they realize that they could have pumped an HD channel and 3-4 SD channels with BETTER quality than a single HD MPEG-2 channel, in their 6MHz band?


Instead, they will have to put up with screams from consumers to steal an SD channel (or two!) from the HD stream.


(sigh) F1 racing broadcast in 12 Mbps MPEG-4.


The conversions of European HD shows for NA broadcast are going to be gruesome.


Gary


P.S. I believe MPEG-2 is supported within MPEG-4. So MPEG-4 means MPEG-2 support.
What do you mean by conversion of HD from Europe to NA as gruesome?. I do not think you understand how television works on professional level.


No HD and I repeat, is captured into MPEG2 or MPEG4. These are compression methods for transmission. Capture of HD is done either uncompressed or slightly compressed on professional formats like D5 from Panasonic or HDCAM from Sony. It is only compressed to MPEG for transmission. The only conversion from European HD is frame rate. In Europe it is 50Hz (slightly lower quality than 60Hz) and has to be converted to 60Hz for NA or Japan.


Also, when ATSC standard was set MPEG2 was the best. There was no MPEG4 or for that matter any other video codec that even came close.


We are watching HD now. If we waited we would be like in Europe. They are only planning for HD and not watching. However, there is one channel there, called HD1 on satellite which uses MPEG2 and has very small selection of programs.


It would be possible to change now but all the OTA tuners out now would be useless. Besides this only pertains to OTA. Satellite is going to MPEG4 soon. D* will be using MPEG4 this summer. They will be the first in the world.


P.S. MPEG2 is separate standard from MPEG4. There is no such thing as MPEG2 supported in MPEG4. Use of MPEG4 does not guarantee the use of MPEG2 and vice versa.
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Quote:

Use of MPEG4 does not guarantee the use of MPEG2 and vice versa.

End of quote.


Of course MPEG4 is totally different animal than MPEG2 and having MPEG4 capable player doesn't mean it can decode MPEG2. However compatibility with SD DVD (promised by both camps) will require that they will have MPEG2 codec built in regardless.
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Wow, lots of bad info here...


HD-DVD decks must be able to decode MPEG-2, H.264 MP and VC-1.


BD-ROM decks must be able to decode MPEG-2, H.264 HP and VC-1.


If you think either HD-DVD or BD-R* will encode/transcode to either H.264 MP/HP or VC-1 out of the gate, you're insane...they will record MPEG2 bitstreams via Firewire. Period. Real-time, single pass (advanced codec) encoders are too expensive to be used at either format's launch...maybe down the road some day.


HD DVD-ROM is available in 15GB SS/SL and 30GB SS/DL flavors. Yes, Memory-Tech has developed a hybrid DVD5 + HD DVD-ROM-15 SS disc, but Cinram has developed a hybrid DVD9 + HD DVD-ROM-15 DS disc. It is important to note that if market conditions warrant it, because HD-DVD easily supports dual sided varients, a hybrid DVD9 + HD DVD-ROM-30 DS disc could be introduced with minimal work (Cinram was working on one, but dropped it due to lack of perceived Hollywood demand). It is also important to note that HD-DVD/DVD hybrids are inherently easier/cheaper to manufacture than BD/DVD hybrids.


H.264 MP/HP decoder chips are available now from multiple players.


VC-1 is finished from a silicon perspective--it's being held up within SMPTE for political reasons only.


VC-1 decoder chips are available now from multiple players.


Single chip MPEG2/H.264/VC-1 decoder solutions are appearing as we speak (e.g., Sigma SMP8630), and they will be available in volume from multiple players in time for HD-DVD's format launch (which will be before BD-ROM's format launch, baring something like AACS getting held up).
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Quote:
Originally posted by CKNA
What do you mean by conversion of HD from Europe to NA as gruesome?. I do not think you understand how television works on professional level.
I should qualified better. I meant live broadcasts. Read my line above that statement.


Given Europe will probably be broadcasting in MPEG-4, a simulcast for North American (e.g. World Cup 2006) would have to re-encoded. That has

responsibility (who will do it?), capability (who will be able to do it?) and quality (what will it look like?) issues.


Enlighten me.


Gary
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