[SCProCalibrator]


I was looking at the process of enabling Creative Dolby Digital Live 5.1 audio for my setup - Creative X-Fi Titanium + Astro A50 Dolby Digital 5.1 headset/DAC. There are 2 ways:

 

1. Enabling Dolby Digital Live encoder in Creative Audio Control Panel, selecting "Speakers" as the primary audio device in Windows Audio settings, configuring them to 5.1, and then using "Speakers" in WASAPI mode to reproduce audio. It also requires you to set LAV Audio and JRiver (or whichever player) to 5.1, but you cannot enable Dolby Digital in LAV Audio and in JRiver and "Bitstream over SPDIF" in JRiver because its blocked by enabling Dolby Digital Live encoder in Creative Audio Control Panel that actually utilizes SPDIF output, even though "Speakers" need to be selected as the audio device. If you try to enable Dolby Digital and "Bitstream over SPDIF" in JRiver or LAV Audio using this method - you will get loud hissing noise or silence. Creative says that using this method actually bitstreams audio, but AFAIK it may be bitstreaming, but not bitperfect bitstreaming.

 

2. Disabling Dolby Digital Live encoder in Creative Audio Control Panel, selecting "SPDIF" as the primary audio device in Windows Audio settings (configuring SPDIF to 5.1 in Windows Audio Settings is not possible), enabling Dolby Digital and 5.1 in LAV Audio and in JRiver, and selecting SPDIF WASAPI to reproduce audio along with selecting "Bitsream over SPDIF" in JRiver. This way you get bit-perfect bit-streaming. I am not 100% certain how VideoClock works in JRiver comparing to ReClock, but I assume it prevents audio speed correction when "Bitstream over SPDIF" is enabled, just like ReClock does or else its not bit-perfect...

 

The first method requires you to enable Dolby Digital Live in a control panel, but the second method does not. The second method let's LAV Audio and JRiver use Dolby Digital bitstreaming over SPDIF. So, does that mean that ANY soundcard with optical digital SPDIF output can do Dolby Digital Live when Dolby Digital is set in LAV Audio and JRiver? That means the whole Dolby Digital Live is just a gimmick.

 

I have an onboard Realtek soundcard (ALC892) that has much better drivers than Creative. Here is the spec list -  http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=284 that lists DTS, but not Dolby Digital Live. Can I still use it for 5.1 Dolby Digital over SPDIF just like my Creative X-Fi soundcard? If so, I can sell my X-Fi Titanium! It is supposedly better in video games but there has been no substantial evidence that it or PC somehow perform better, only that Creative drivers suck big time! Today's CPU like 3770K @ 4.5Ghz can process sound without a discrete soundcard without any FPS loss AFAIK.

 

[Andy_Steb]

Dolby Digital Live is Not needed to play Dolby Digital tracks on your computer.


Dolby Digital Live is more for gaming. SPDIF can only carry 2 channel PCM. So if you wanted to play a game in surround sound on your AVR, you would have to convert the multi-channel PCM to Dolby Digital.


Now with HDMI you can play Multi- channel PCM, so the need for Dolby Digital Live is gone.

 

[SCProCalibrator]


Wait... the second method I described allows you to use SPDIF 2ch but the sound is actually bitperfect bit-streamed Dolby Digital 5.1. I used a special test file encoded with DD5.1 and the sound really was positional 5.1. But from what I understand it was the JRiver and LAV Audio Decoder that enabled Dolby Digital 5.1, right?  Why can't games do the same? Can't I just select SPDIF as a default device and then select 5.1 speakers? If SPDIF Out cannot be selected as a default audio device then that is when Dolby Digital Live encoder is useful. 

 

[Thrillho]

A DD5.1 stream is a compressed format and "shrinks" the six channels of information down to be small enough to pass over the limited bandwidth of spdif. Think of it like making an MP3 out of a CD track. Without that compression you can only pass two channels over spdif. When you play back a movie file it has a pre-compressed soundtrack that is ready to playback over spdif.

Games generate audio realtime, when you shoot your gun or hit the gas it makes those sounds happen, these can't be pre-compressed as there is no sound track file to work with.

Realtime compression takes CPU power so a DDLive sound card has special hardware to offload that so it doesn't affect game play.

It's kind of becoming a moot point as HDMI has nearly replaced SPDIF as the standard digital interface and it doesn't need the sound to be compressed to playback surround sound.

 

[SCProCalibrator]


Thank you for explanation!

 

Are there many gaming headset that use HDMI? Also, I am not sure how many soundcards have HDMI ports. I know nVidia and AMD videocards have onboard sound, but it doesn't support any Surround Sound. 

 

For games though, DDL sends compressed audio to headsets, which then use the Dolby Headphone technology to reproduce positional audio. There is no advantage to DD5.1 headsets as Dolby Headphone sound can be virtualized by almost any soundcard, including Realtek HD codecs, and then sent over to regular stereo headphones to produce positional 5.1 sound, even without an amp/DAC. It works for games, but it is not possible to actually have bit-perfect bitstreaming in WASAPI mode since the soundcard will take info from all the channels and virtualize a stereo signal that will create a positional sound effect, which means the sound won't be untouched/bit-perfect. That really makes DDL 5.1 soundcard and headsets a gimmick, even for games, right?

 

[Foxbat121]

Dolby Digital is not bit perfect. It is a lousy compression like jpeg on pictures.

 

[SCProCalibrator]


Yes, that also crossed my mind. Its bit-perfect from soundcard to DAC, but from source to DAC as the soundcard compresses it. However, its not as compressed as WAV to MP3 or BMP to JPG. I would still like to know if there are any advantages to Live 5.1 Dolby Digital encoding when it comes to games vs Dolby Headphone positional audio.

 

If not - I will sell my sound card along with my headphones and buy what I really want - G-Sync! Not only for the G-Sync feature but also for the fact that new modes drastically improve color accuracy on the only TN panel that supports G-Sync. I have that panel VG248QE and I hate its LightBoost mode colors... Its not capable of producing a neutral grayscale - that is how bad it is...

 

[Foxbat121]

If the game can generate Dolby headphone effects, there is no advantage going through this DDL then feed to Dolby headphone process. Don't confuse it with Dolby Surround effects though. Not the same thing.


Any modern PC's onboard sound chip can easily handle multi-channel audio. When output to a. HDMI receiver, it is a true lossless surround experience. There isn't any need for DDL anymore. Yes, Sony makes two HDMI surround headphones but they are sold in Japan only.

 

[SCProCalibrator]


What do you mean by "If the game can generate a Dolby Headphone effect" ? I thought a game would simply have to support 5.1/7.1 audio, and the soundcard would process signal from 5.1/7.1 channels and mix it into virtual-surround stereo signal that will result in positional audio on stereo headsets. It can send that processed stereo signal over SPDIF too! That is how my friends explain it to me. They just buy a good Sennheiser stereo headset, a decent DAC, and use whichever soundcard they have. Does a soundcard have to specifically support Dolby Headphone feature though? My ALC892 only supports DTS, not Dolby Digital, but Dolby Digital and DTS are NOT the same as Dolby Headphone, right? I do hear many people complaining that their onboard Realtek (ALC892!) soundcard produces very muffled Dolby Headphone audio, but the Xonar soundcard produces clean and clear sound... 

 

[Foxbat121]

I don't know any soundcard have Dolby headphone Built-in. It costs a lot of money to license from Dolby Labs in either software or a hardware chip. Virtual surround is not the same thing as Dolby Headphone. Far from it and they are worthless.

 

[SCProCalibrator]


Er.. Dolby Headphone IS virtualization because it uses TWO speakers to produce SURROUND 5.1/7.1 sound. It may be of higher quality though. I know ASUS Xonar DG supports it, but not sure about ALC892...

 

[Foxbat121]

Correct, Dolby Headphone is a virtual surround system. But virtual surround does not equal to Dolby Headphone. Dolby headphone is the only thing that really works. Everything else are just BS.


Onboard sound cards don't usually support it in hardware because that's not how it is typically used and it costs a lot to license it.

 

[Thrillho]

Ton's of Sound cards support Dolby Headphone, the Entire Asus Xonar series, The HT Omega series, most other cards based on the C-Media chipsets. The Creative Labs Cards have their own headphone surround formats, CMSS-3D on the Xfi and earlier, SBX ProStudio on the newer cards. Honestly, a good set of traditional headphones used with any of these options will kill a "Gaming" headphone in quality and positional effect. The added bonus is then you've got a decent set of music headphones as well.

Side note from earlier in the thread. The AMD/nVidia video cards support surround sound from both movies and games. Games do their own sound processing now and do not rely on APIs provided by a sound card (EAX, DS3D, OpenAL,etc) and all the Sound device is doing is being an output. HDMI being able to pass 7.1 channels of LPCM digitally and does not require DDL or any other compression which you assume is not as bad as MP3 from a WAV but in fact it's taking the LPCM stream which is equivalent to WAV and compressing it to 640kbps, since that contains six channels worth of info, you could infer it's roughly equivalent to a VBR0 MP3 in terms of bitrate per channel (I'm assuming it compresses the Surround and LFE channels heavier than the rest and distributes the remainder evenly).