The Official Gigabyte GA-MA78GM-S2H RS780 mATX Thread - Page 22

There would be no difference in the resulting sound out of your AVR.

So which model Phenom should we be matching up with this board? Have we figured out which one will enable HT3.0 to work?

I think ANY phenom will. which is why some are waiting for the new lower clocked one to come out.

The 1st option allows you to send HD audio (DTS Master-HD, Dolby Digital +) via bitstream to your AVR for decoding. This is better if the decoders in your receiver are better than the software in your computer

The 2nd option forces you to decode the HD audio formats in the PC and currently there isn't a software solution that will do so without downsampling the result. So you aren't getting the best possible sound quality with the 2nd option. If and when that issue is resolved, as long as the software is a decent decoder, then the 2 options should be equivalent. In fact, the 2nd option may be preferred if your AVR doesn't support HD audio.

Well, if your receiver has the ability to do the decoding, then your processor in your computer wouldn't have to do the decoding to make the X.1-channel LPCM. This being said, the addition on a modest (~$90) cpu is only an extra 5-10% cpu usage according to a recent review. So it is really only a question of where it is decoded. Also, it may be that lip-sync adjustments can't be made in your receiver with multi-channel lpcm, but I don't know for sure if that is another limitation or not. Someone else may be able to answer that. Lastly, there is a software issue that apparently limits (downsamples) the audio bit-rate which should be fixed some day unless the studios are behind that "limitation".

The decoding of any HD bitstream is identical no matter what device does it. This isn't DAC, this is just digital decoding, which will result in the same digital LPCM everywhere - PC or AVR or BD player.

As for the downsampling, it's unclear if this is a real issue or not, especially given the current source resolutions. But as far as I know, PDVD 3370 produces LPCM at the quality of the original soundtrack.

Well, yes and no. If you turn on DTS Interactive you are basically doing that for everything that is not already a native DD or DTS file/track. I can run native 44.1 for the default audio, but that means DTS real-time encoding is off. If I turn on DTS Interactive I can no longer get anything for my music other than the on-the-fly DTS mix that it pumps out, so depending on what you were expecting it does work.

OK, the DTS-connect is a good feature for those that want the best possible audio from this board right now for BD discs (aside from the audio's analog 7.1 outputs).

However, is it possible to select within the player that you would rather have the "legacy" AC3 or DTS version instead, and have that as the output over HDMI or SPDIF? Or, do BD discs not contain any AC3/DTS audio?

Another comment regarding the quest for bit-perfection in Vista for 44.1 kHz source files - Although 44.1 can be selected as an output here, which is a good thing, there has yet to be reported, at least as far I can see, someone who has been able to achieve bit-perfection. Correct if wrong...

Thanks for the confirmation, that is exactly what I was expecting. It would be great if it was smart enough to switch between 2-ch PCM and DTS Interactive based on number of channels playing, but I wasn't hoping for that much.

Sadly, both Dolby Digital Live and DTS Connect seem to operate under the asumption that always encoding anything that is PCM into AC3/DTS is the only way to go, and that it ought to be sent to all 5(.1) speakers.

This is a boon for converting decoded TrueHD, DTS-HD, and LPCM from Blu-ray and HD DVD discs to something S/PDIF can handle but may not be desireable for good old stereo music, although for low resolution things like MP3s I've not noticed a real issue when using DDL or DTS Connect.

Most Blu-ray releases have a "legacy" track either because they use DTS-HD which has the concept of a 'core' and others that use TrueHD or LPCM often include an AC3 track as an option.

You can choose these legcay tracks from the audio options menu of any disc that has the soundtrack. But you'd also need to set up the player for S/PDIF passthrough, which means stopping the movie and changing the audio preferences, since under DDL or DTS Connect you'd want to set the player to5.1-channel or 7.1-channel audio (depending on your setup) and let the player decode the audio into multi-channel PCM for DDL or DTS Connect to then encode for S/PDIF transport.

why can't you use a vga to component adapter?

Those aren't for normal uses. VGA and component aren't the same signal, and thus can't just be 'adapted', they need an active transcoding from RGBHV into Y/Pb/Pr. Those VGA adapters you may find around are for specific models of [typically] home theater projectors that have a VGA port on it, but don't include a component input for back panel space saving purposes, in this case they have a proprietary ability to accept either a VGA or a Component video signal.

heres a quote from the GB website for this board:

link


Is 8 channel over HDMI possible in any way? LPCM - no. DTS-HD - no. DD trueHD - no.

is this an out-and-out lie from GB?

I thought it's just a general description of HDMI or an honest mistake. 8-channel audio through HDMI is impossible with 780G.

My experience with this is you won't need to change anything for Media Center on OTA HDTV (ATSC) programs or DVD files (off disk or HDD). What I mean is it will do the DTS encoding for 2-channel files (wav, mp3, mp4, etc.), but when it encounters a 5.1-genre native DTS or Dolby Digital (AC3) track it automatically goes into spdif passthrough if that is how you have the audio set in Media Center. I do not have any way to test this for HD-DVD or BluRay at this moment, and I understand there you are using the PowerDVD or some other player (not WMP through MC).

I guess my point is that I don't see a need for a DTS-Connect at all. If I want to play my music files, I wouldn't want any re-encoding or matrix (DTS:Neo) at all. If I play BD disc, I would rather have the "core" DTS, as you say, or the normal AC3 track played instead. And, I'm assuming that both music and vanilla AC3/DTS can be played over HDMI. Is that correct? If not, SPDIF is fine, too.

So, what it would boil down to for me at least is having SPDIF pass-through always enabled, and DTS Connect always disabled so that I can enjoy the native sound format, seeing as how TrueHD and other higher quality audio is impossible, digitally speaking.

The point is that SPDIF can't handle multi-channel PCM (more than 2 channels). So if you have something that is producing 6 or 8 channels of PCM, and all you have is SPDIF, you need DDLive or DTSConnect to get that audio to your AVR ove SPDIF and maintain the multiple channels. This is an issue with playing BD/HD discs and the HD soundtracks, as well as many games that produce multi-channel PCM only.

With HDMI audio support in PC's, this is no longer an issue since you can send the multi-channel PCM over HDMI (along with the video). But were very very early in the HDMI audio era for PC's.

Boy, I'm really torn. I can't even make up my mind to go with a board like this along with an efficient AMD processor, or with a tried and true P35 chipset along with something like an E2200 processor with an ATI 2600 Pro video card.

Aside from cost, power, cooling, is there anything else to consider for those really debating on going the integrated route in the form of this motherboard? I mean, with a P35 chipset, at least it would be possible in a near future upgrade to obtain full digital TrueHD out of a video card, correct? Or, would that require some new-fangled connection on the motherboard, necessitating a new motherboard purchase in the future anyway?

We're talking about <$90 MB's here. I would just get whatever you want now, including the G35 if you want to try out mult-channel PCM today over HDMI (since the G35 is the only thing available today that does this), and then get a better MB whenever they come out.

It's not really a big expense in the HTPC world.

Deciding to build a htpc has been quite the learning experience! I haven't bought a HDTV yet and so I'm experimenting with two older tv's. One takes S-Video / composite. The other takes component YPbPr. Since I cannot hook these up directly to the integrated video I'm guessing a cheap route would be to purchase a 3450 like the SAPPHIRE 100234L Radeon HD 3450 512MB 64-bit GDDR2 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card TV-Out HDTV / S-Video / Composite Out which is currently selling for $40. Plus, then I can try hybrid crossfire and maybe even play a game.

If anyone could advise if this seems reasonable I'd very much appreciate it.

sounds like a good solution for you to try out things at a reasonable price

Yep sounds like a good route

I'll put my comments on this down in the last section, since they relate.


The HDMI specs have way more then enough bandwidth to do everything S/PDIF does and more. Of course in the 780G's implementation it is effectively S/PDIF over HDMI so the same restrictions/limitations apply, this isn't the case with other chipsets that can pass multi-channel PCM such as Intel's G35, the upcoming GeForce 8200 and (presumedly) Intel's upcoming G45.


Yes but, you're missing something. When you use DTS Connect what you're getting is the lossless audio track that has been decoded by the player (i.e. PowerDVD Ultra) into PCM (which is raw uncompressed digital audio) for the PC to use, mix, etc. DTS Connect then takes this uncompressed audio and compresses it into 1.5Mbit/s DTS. So yes it's lossy. But it comes from a lossless source. You get a trickle down benefit of having the source being lossless data. Choosing the legacy DTS core or AC3 track doesn't. You are choosing to use a lossy version that has no headroom, no extra bitrate, etc. I would think that it is preferable to take the lossless (i.e. perfect) version and then compress it down a bit. Just like how resizing a high resolution image retains some of the detail of the source, or displaying 1080p Blu-ray content on a 720p TV still looks amazing. You're still getting the best you can at the source point, it's only at the transport (S/PDIF) point that this high resolution has to be compromised.
This, by the way, is how the set-top HD DVD players and many Blu-ray players behave when using S/PDIF. They have a Dolby or DTS licenced encoder to do what DTS Connect or Dolby Digital Live do on the PC.

Now as an aside, even the 'legacy' tracks on these disc sound pretty darn good. This is because they typically use the maximum bitrate the standard DTS (1.5Mbit) or Dolby Digital (640Kbit) codecs allow. Standard DVDs didn't. AC3 on DVD max'ed out at 448Kbit/sec, and DTS was typically only used at 768Kbit/sec on DVD. So they will still sound at a least somewhat noticeably better. Experts in the audio field agree with this (it was said by film sound professionals in the now dead Industry Insider's threads from the HDTV Software Media Discussion forum here on AVS).

In addition to what is said above, you should also be aware that there are actually quite a few Blu-ray discs that only have LPCM without any legacy DD or DTS track.

EDIT: This turns out to be false. See posts by SpHeRe31459 below.

Actually the Blu-ray specs require a legacy track be available.

Well, this is all semantic and most likely no one would be able to tell the difference between selecting a legacy soundtrack on a BD disc and allowing DTS-connect do its magic anyway. That said, I can't imagine that DTS-connect would sound better than a studio-compressed AC3/DTS version. After all, the studio has the master, and presumably, that master, which is most likely the same, bit for bit, if mastering digitally, as the uncompressed 8 channel LPCM data that would be decoded by the PC software. So, in the end, I would assume that the studio would have done a better job (3-pass encode, etc.) with the master in producing the legacy track (AC3/DTS) than a PC's real-time DTS-connect encode.

In short, taking lossless, DD+ or DTS-HD HR and compressing it to 1.5 Mbps DTS with DTS Connect will be better than playing any legacy track that has a bitrate lower than 1.5 Mbps (ie, legacy DD or DTS at 768 Kbps). If you have a legacy DTS track encoded at 1.5 Mbps, then I don't think selecting a lossless track and using DTS Connect to downsample would be beneficial. The only advantage in that scenario would be that you could perform mixing with the lossless audio if you're using special features on the disc that require it.