HD Audio Pass-through

[Ditto666]

I've heard there's a way to do that (also without messing things up for other formats) using just AC3Filter or FFDShow Audio. Just enabling SPDIF for AC3 and DTS doesn't work. For DTS-HD specifically, which I'm actually more interested in, it basically just sends the lossy regular DTS format like that. I've tried it in every container and combination possible but as would be expected, that didn't help anything. I've also tried from several different sources. So, is this possible? In simple terms anyway... If so, how? :) Thanks!

[nurbs]

No, S/PDIF doesn't have enough bandwidth to support DTS-HD.

[saint-francis]

No, S/PDIF doesn't have enough bandwidth to support DTS-HD.

While I'm not disagreeing with you that it doesn't work, I find it difficult to believe that fiber is lacking the bandwidth.

[nurbs]

SPDIF was designed for 16bit 48kHz stereo PCM. That's 1.5 Mbps. The most SPDIF can do is 24bit 192kHz stereo AFAIK. That's around 9 Mbps and it's not supported on all devices. DTS-HD on Blu Ray can go up to 24.5 Mbps.

[kieranrk]

There is a spec for carrying "HD Audio" formats down SPDIF. It is possible but I doubt any devices support it.

[mindbomb]

i guess you can if you downmix it to 2 channel pcm.

[dansrfe]

So this is about going through the S/PDIF through another cable other than the HDMI cable right? Because I can send DTS-HD completely fine to my HD receiver over HDMI passthrough with ffdshow.

[Ditto666]

So this is about going through the S/PDIF through another cable other than the HDMI cable right? Because I can send DTS-HD completely fine to my HD receiver over HDMI passthrough with ffdshow.

I forgot to specify - I meant through HDMI, yes. The option to carry the sound directly is by SPDIF so that's why I said that specifically. My question was more simply I guess along the lines of, how do I play DTS-HD audio through my receiver?

You said you get it to work with FFDShow? How? I can either play it first transcoded to PCM or with just regular DTS.

[nurbs]

Open the ffdshow audio configuration, go to output, check DTS-HD and any other format you want in the "pass-through" box. If the box doesn't list the formats and doesn't list HDMI your ffdshow version is too old. Your receiver has to support decoding the formats for this to work obviously.

[Ditto666]

Open the ffdshow audio configuration, go to output, check DTS-HD and any other format you want in the "pass-through" box. If the box doesn't list the formats and doesn't list HDMI your ffdshow version is too old. Your receiver has to support decoding the formats for this to work obviously.

Oh.. I thought I had the newest version. I never know how to find the newest or maybe the new version is just very recent? I have version 3094 - 10/3/09. So people couldn't play DTS-HD before the version that followed this one? There has to have been a way before 2010, lol. I also want AC3Filter to be my default for everything so is there a way to set the new version of FFDShow Audio (if I find it) to only work for DTS-HD? Thanks.

[janos666]

A good place to pick up some fresh FFDShow SVN builds: http://xhmikosr.1f0.de/

I can't understand your thread. It asks about SPDIF and HD. It's not possible with any known receivers. (Simply, because old SPDIF receivers don't support these HD formats and the new HD supported devices feature HDMI connectors. And the SPDIF doesn't familiar with HD formats: may be there is some new standard to do it but I think nobody will adapt it when they have HDMI connectors on their HD compatible devices and it's easier...)
Can you name your receiver?

[Ditto666]

A good place to pick up some fresh FFDShow SVN builds: http://xhmikosr.1f0.de/

I can't understand your thread. It asks about SPDIF and HD. It's not possible with any known receivers. (Simply, because old SPDIF receivers don't support these HD formats and the new HD supported devices feature HDMI connectors. And the SPDIF doesn't familiar with HD formats: may be there is some new standard to do it but I think nobody will adapt it when they have HDMI connectors on their HD compatible devices and it's easier...)
Can you name your receiver?

I think I confused what SPDIF is... I thought SPDIF was just bitstreaming, or in other words, streaming the data directly to the receiver instead of having it decoded first. I probably understand this wrong...

I have the receiver that comes with Onkyo HT-S6100 HTiB. It supports DTS-HD, TrueHD, and therefore has HDMI of course, lol.

[nurbs]

Since you didn't know what it is did it ever occur to you to look it up? You could have just googled it if you wanted to know what it is and what it supports. This is SPDIF: http://en.wikipedia.org/wiki/Spdif

[Ditto666]

Since you didn't know what it is did it ever occur to you to look it up? You could have just googled it if you wanted to know what it is and what it supports. This is SPDIF: http://en.wikipedia.org/wiki/Spdif

Umm... I thought I did know what it was and my question wasn't in regards to it. Why the hostility? You know what my question was - wth man... I basically wanted to ask how to get DTS-HD working and thought the way it's done is through S/PDIF which I now know was wrong. I should've said "pass-through" which I though was the same thing... I would apologize but I'm not sure for what.

[dansrfe]

Tick DTS-HD in ffdshow for pass-through in HDMI. In fact tick all the boxes for pass-through since your receiver supports it and personally I like audio being sent untouched to the receiver then having the receiver decode it. If it doesn't work for you still then you need to change some settings in either MPC or your audio settings but just post a follow-up here and we'll try to figure out what's going on.

[nurbs]

I would apologize but I'm not sure for what.
How about for wasting everyones time with a thread title and first post that have nothing to do with the question you actually wanted to be answered?
If you ask how to send DTS-HD over SPDIF (specifically) is it really too much to expect from you that you at least know what SPDIF is?

[Ghitulescu]

While I'm not disagreeing with you that it doesn't work, I find it difficult to believe that fiber is lacking the bandwidth.
It's not the fiber the limiting aspect here, it's the standard.
S/P-DIF is not optical, it is also coax. Actually, S/P-DIF like any other transport protocol, like the network ones, has several layers. As nurbs said, the S/P-DIF was created with DAT specs in mind. Both the transport layer and the logical layer have been adopted to transport a max. 1.5Mbps signal. S/P-DIF allows custom data formats, this is how AC-3 and DTS are transported, because they are compressed. Using the custom data format, everything can be transported, provided the bitrate is below the specs and both the sender and the receiver understands that compressed format.
There is a spec for carrying "HD Audio" formats down SPDIF. It is possible but I doubt any devices support it.
If it's not in the S/P-DIF specs, then it's not S/P-DIF. It may be one of the custom data, see above.
I think I confused what SPDIF is... I thought SPDIF was just bitstreaming, or in other words, streaming the data directly to the receiver instead of having it decoded first. I probably understand this wrong...
Read then the S/P-DIF standards, IEC 60958, especially the first part, which defines the physical layer.

[Ditto666]

Tick DTS-HD in ffdshow for pass-through in HDMI. In fact tick all the boxes for pass-through since your receiver supports it and personally I like audio being sent untouched to the receiver then having the receiver decode it. If it doesn't work for you still then you need to change some settings in either MPC or your audio settings but just post a follow-up here and we'll try to figure out what's going on.
I think I'll get it to work, thanks. I just had an outdated version of FFDShow audio. I didn't think much would have changed in a year. I am wondering if I'd be able to get FFDShow as the preference for only HD audio though...
How about for wasting everyones time with a thread title and first post that have nothing to do with the question you actually wanted to be answered?
If you ask how to send DTS-HD over SPDIF (specifically) is it really too much to expect from you that you at least know what SPDIF is?
It's not too much to expect to be honest, but the fact of the matter is I made a mistake. It obviously wasn't intentional. I did know what SPDIF was sorta, and I just thought that the way it's done, HD audio, is the same way. I've never done it so therefore didn't know. Damn man...

Basically to sum up the query and response, it's as simple as:
Q- "How do I send HD audio to my receiver simply and easily?"
A- "Get the latest version of FFDShow Audio which supports it."
"OH, I didn't know that! Thanks!"
Maybe I'd ask some follow up questions. That's pretty much all. Why the fuss?...

[kieranrk]

If it's not in the S/P-DIF specs, then it's not S/P-DIF. It may be one of the custom data, see above.


It is in the SPDIF spec as one of the data formats.

[darkbasic]

What does happen if I connect the pc to the amplifier with an HDMI cable and I play an AAC 5.1 audio stream? It sends the uncompressed stream?

[Ditto666]

What does happen if I connect the pc to the amplifier with an HDMI cable and I play an AAC 5.1 audio stream? It sends the uncompressed stream?

Most likely.

[darkbasic]

So why should I want an amplifier with DTS/AC3 audio support if I can send the uncompressed stream?

[Ditto666]

So why should I want an amplifier with DTS/AC3 audio support if I can send the uncompressed stream?

There are differences in the decoding of the formats by the receiver. This applies for everything, but something to easily understand is DTS-ES (http://www.dts.com/DTS_Audio_Formats/DTS_Digital_Surround_PLUS_Extensions/DTS_ES.aspx) for example.

It takes 5.1 audio and upmixes it to 6.1 using the built-in matrix functionality designed by Digital Theater Systems, inc.. That's what support for it means, that it uses its matrix for distributing the sound. Decoding the format prior and sending it uncompressed is in every sense the same quality, but the receiver handles it differently - not as intended, and in my opinion, worse. And that's only opinion when it has to do with regular DTS or AC3, without major intended changes afterward..

[nurbs]

@darkbasic:
Everything Ditto666 said in post #23 is wrong. There is no difference unless your software decoder doesn't handle the file properly (e.g. can only handle the core of a DTS-HD track), can't decode the audio at all or the connection can't support the decoded audio (e.g. 6 channels on SPDIF).

There are benefits of bitstreaming to the receiver. You reduce cable clutter, it can make it easier to use the same speakers for multiple devices, you can use formats your player can't handle natively and you can make use of whatever processing the receiver has built in.
There are probably other benefits I can think of, but under normal circumstances quality isn't one of them.

[darkbasic]

You reduce cable clutter

Uh? How? Don't you need an HDMI cable anyway?

[toby702]

you can if you downmix it to 2 channel pcm.

[Ditto666]

@darkbasic:
Everything Ditto666 said in post #23 is wrong. There is no difference unless your software decoder doesn't handle the file properly (e.g. can only handle the core of a DTS-HD track), can't decode the audio at all or the connection can't support the decoded audio (e.g. 6 channels on SPDIF).

There are benefits of bitstreaming to the receiver. You reduce cable clutter, it can make it easier to use the same speakers for multiple devices, you can use formats your player can't handle natively and you can make use of whatever processing the receiver has built in.
There are probably other benefits I can think of, but under normal circumstances quality isn't one of them.
Nice... How professional :rolleyes:
Uh? How? Don't you need an HDMI cable anyway?
Yes, obviously you'd need an HDMI cable either way. Nurbs has just developed some dislike towards me. Dunno what his problem is.

I gave you the information; now you have my word and his. It's really up to you to make up your mind from here; look into the things I mentioned maybe. The only thing I can tell you with 100% certainty on which point I'm right is in regards to things like DTS-ES. Disney Pixar uses that format often like recently with UP and Toy Story 3, of which I personally saw. The audio is 5.1ch DTS and the receiver picks it up as made for the DTS-ES matrix and upmixes it to a rear channel. That would not happen if it were decoded first and sent uncompressed.

[Ghitulescu]

It is in the SPDIF spec as one of the data formats.

I am aware of the following IEC 61937 formats: PCM, AC-3, MPEG, DTS, MPEG AAC and Atrac (including TA4). While all these formats do not exclude higher sample rates and/or higher bit depths (ie HD audio), one should always remember that the signal has to travel using an S/P-DIF interface as defined in IEC 60958-1, ie limited.

I hope you don't confuse S/P-DIF with the optical interface (Toslink) like many do, since exactly the same Toslink is used for decades to transport eg ADAT audio.

[nurbs]

A DTS-ES compliant software decoder will send 6.1 audio to your receiver. There is no difference in quality between that and bitstreaming the audio. If you only have a DTS decoder it will decode it as 5.1 and send that to the receiver. I covered that under "decoder doesn't handle the file properly".
ffdshow doesn't do DTS-ES natively, so if you use that bitstreaming that format makes sense.

About the cable clutter: That sentence was listing a few benefits of using bitstreaming, receivers and HDMI in general. I should have been more specific.

[darkbasic]

since exactly the same Toslink is used for decades to transport eg ADAT audio.

ADAT too isn't so good. You can have maximum 8 48KHz channels. If you want 96KHz 7.1 you can't use ADAT.

[Ditto666]

A DTS-ES compliant software decoder will send 6.1 audio to your receiver. There is no difference in quality between that and bitstreaming the audio. If you only have a DTS decoder it will decode it as 5.1 and send that to the receiver. I covered that under "decoder doesn't handle the file properly".
ffdshow doesn't do DTS-ES natively, so if you use that bitstreaming that format makes sense.

About the cable clutter: That sentence was listing a few benefits of using bitstreaming, receivers and HDMI in general. I should have been more specific.

Find me a decoder compatible with it and then we'll talk. But umm... even if you do, I'm sure it won't be the native decoder for the format that DTS, inc. created, as the decoders aren't for regular DTS. Even if they decode the format "correctly", doesn't make it the same.

Even if it was the native decoder lets say and the data was sent uncompressed to the receiver, it's not likely that the receiver will process the data, or rather, balance the audio throughout the speakers the same way as it would a DTS stream. The formats are simply processed differently in terms of the output they give.

If you somehow masked a purely DTS stream as PCM, and the receiver registered it as an uncompressed signal, the audio would sound differently mixed than if it got the signal as it should have.

[nurbs]

Arcsoft TMT3 comes with a certified DTS-ES decoder. In fact if you find a DTS-ES decoder in any commercial product chances are that it is certified, because most companies won't risk getting sued over licensing.
Video and audio formats have specs, test suits and reference decoders. It doesn't matter who writes a particular implementation as long as they stick to the standard. You don't seriously believe the hardware decoder in your receiver was designed by DTS Inc. themselves?

If you send the decoded 6.1 stream to the receiver it doesn't have to do any balancing, all it has to do is to pass it on to the speakers. There is no difference between doing the decoding and reconstructing the 6th channel in software or letting the receiver do it.

If you somehow masked a purely DTS stream as PCM, and the receiver registered it as an uncompressed signal, you would hear noise, if anything, on the speakers. You can't treat a compressed signal as PCM and get anything resembling the actual audio content out of it.

[Ditto666]

Arcsoft TMT3 comes with a certified DTS-ES decoder. In fact if you find a DTS-ES decoder in any commercial product chances are that it is certified, because most companies won't risk getting sued over licensing.
Video and audio formats have specs, test suits and reference decoders. It doesn't matter who writes a particular implementation as long as they stick to the standard. You don't seriously believe the hardware decoder in your receiver was designed by DTS Inc. themselves?

If you send the decoded 6.1 stream to the receiver it doesn't have to do any balancing, all it has to do is to pass it on to the speakers. There is no difference between doing the decoding and reconstructing the 6th channel in software or letting the receiver do it.

If you somehow masked a purely DTS stream as PCM, and the receiver registered it as an uncompressed signal, you would hear noise, if anything, on the speakers. You can't treat a compressed signal as PCM and get anything resembling the actual audio content out of it.

Of course I know that would happen, that it would come out as noise. I didn't mean "mask" it as PCM. It's why I said "if" - if that were possible...

I'll take your word that that's how it should be. It would make sense that way. All I can say for sure then is that my receiver is retarded because it treats the sound differently, but in a way that makes sense TBH...

Before I say anything else, let me ask you a question then so that I don't get an unexpected response. Without any setting changed in AC3Filter, should I hear a difference between having it decode the sound vs. sending it through S/PDIF?

[nurbs]

I don't use AC3filter. It depends on what the defaults in AC3filter regarding Dialog Normalization, DRC, gain control, output format, ect. are.

[Ghitulescu]

ADAT too isn't so good. You can have maximum 8 48KHz channels. If you want 96KHz 7.1 you can't use ADAT.
Like the DAT before, ADAT had its technical importance, nowadays faded. DAT and ADAT are still used in some small studios and radios.

The point of mentioning ADAT was to show the confusion that appears to exist, most people still confound the connector with the standard (they're helped by some manufacturers, too, that label anything digital as SPDIF).

[Ditto666]

I don't use AC3filter. It depends on what the defaults in AC3filter regarding Dialog Normalization, DRC, gain control, output format, ect. are.

Well alright, it doesn't really matter what then - FFDShow.

[nurbs]

Should sound the same if the output is set correctly.

[Ditto666]

Should sound the same if the output is set correctly.

But it doesn't. It's quite significant actually. Most people will be able to tell. What's different is how the sound is distributed, sorta like I was saying. I checked multiple times and everything is how it should be. There's nothing extra going on or anything like that. I have an Onkyo receiver from then HT-S6100 HTiB. Not likely it's doing anything funny. Am I, along with others, delusional?

It's hard to say which way is "better" but streaming the DTS sounds more likely as intended. There's a difference nonetheless.

[nurbs]

I'm sorry to hear you are having trouble with your setup, but that you believe everything is set up correctly doesn't mean that it is.
I would be surprised if you could find a large number of people who would agree that bitstreaming is inherently superior and will deliver different results from decoding in a (compliant) player, except maybe in the audiophile community.

[darkbasic]

except maybe in the audiophile community.

lol :)

[mindbomb]

Bitstreaming is slightly superior in that you know for sure that there is no downsampling to 16 bit going on.
Also, lower cpu usage.

[darkbasic]

ffdshow is open source, so you know for sure what it does.

[Ditto666]

I'm sorry to hear you are having trouble with your setup, but that you believe everything is set up correctly doesn't mean that it is.
I would be surprised if you could find a large number of people who would agree that bitstreaming is inherently superior and will deliver different results from decoding in a (compliant) player, except maybe in the audiophile community.
How about this then... The forum is supposed to be about helping accomplish just this, so why don't you tell me how to set this up or help me figure out "what's wrong" and I will follow it to the letter.

Also, "the audiophile community" is supposed to be offensive? You think just because you know a few things technically means you know everything and it's all you need to know? If you're referring to somebody that doesn't know what bitrate is and talks about how he/she learned how to rip CDs in the"WAV" format and how amazing it is in quality compared to MP3, then yes actually, that's an insult. If you're talking about an actual audiophile that knows wtf he/she is talking about, then you're an idiot, because it's only because of people like that that specs are upgraded/created - also the only reason they matter in the end. Otherwise, if you don't give a crap, only to KNOW what should be better/same based on a few facts formulating altogether inaccurate conclusions, then why does it even matter? If you don't hear and don't even care about the perceptual audio difference, why bother?

Anyway, that dragged on longer than it should've, sorry. Seriously though, why don't you help me set it up properly since you're so convinced it isn't. I won't lie if it actually ends up being the truth and the sound is actually identical. That's how I'd prefer it actually, but even if I didn't, I don't do that kind of shit. If I learn that I'm being properly informed contrary to what I've thought and experienced, I'm usually happy because it makes me that bit smarter. Should I start with as many details as possible as to what I have going now in my setup?

[nurbs]

I can help you with setting up ffdshow. I can try to help you with AC3filter and your receiver, but since I don't use the first and don't own the second this will prove to be more difficult.
Anyway feel free to post as much information as you can about your setup (software used, settings, connection type, receiver settings, speaker configuration, ect.). It would probably be best to limit testing to AC3 in the beginning. Since the spec is publicly available libavcodec has a compliant implementation and AFAIK decodes it with dialog normalization as is (unfortunately) required for a compliant decoder.

If you think we can thank audiophiles for our current hardware and formats, you apparently never witnessed members of the audiophile community on the web. The most vacal ones usually seems to be clueless about digital audio processing, especially when it comes to lossy formats, and some of them would prefer it if we never switched to digital to begin with. We can thank engineers, researchers, artists and other professionals in the audio industry for the current state of affairs.
Audiophiles are all about feeling, not about facts. They generally also don't like ABX tests :).
What we have to thank the audiophile community for is the persistent myth that Vinyl is capable of better sound reproduction than CDs (because it's analog :rolleyes:) and the 100€ HDMI cable (1m length).

[Ditto666]

I can help you with setting up ffdshow. I can try to help you with AC3filter and your receiver, but since I don't use the first and don't own the second this will prove to be more difficult.
Anyway feel free to post as much information as you can about your setup (software used, settings, connection type, receiver settings, speaker configuration, ect.). It would probably be best to limit testing to AC3 in the beginning. Since the spec is publicly available libavcodec has a compliant implementation and AFAIK decodes it with dialog normalization as is (unfortunately) required for a compliant decoder.

If you think we can thank audiophiles for our current hardware and formats, you apparently never witnessed members of the audiophile community on the web. The most vacal ones usually seems to be clueless about digital audio processing, especially when it comes to lossy formats, and some of them would prefer it if we never switched to digital to begin with. We can thank engineers, researchers, artists and other professionals in the audio industry for the current state of affairs.
Audiophiles are all about feeling, not about facts. They generally also don't like ABX tests :).
What we have to thank the audiophile community for is the persistent myth that Vinyl is capable of better sound reproduction than CDs (because it's analog :rolleyes:) and the 100€ HDMI cable (1m length).

Those are the idiot "audiophiles" I was talking about. I meant people that have a clue. Anyway, no point on staying on that - I'm sure you knew what I meant. I get the dislike for your generalized perception of audiophiles. Logic and rationality is needed to qualify being one. Anyone can call themselves that and as with any populous, there are a lot of people that try to squeeze themselves in there without a clue.

Anyway, in regards to the setup, I'm realizing it would be better to start from zero and change/go back to where the steps in my configuration talk a detour. Let's start with having a brand new receiver, one similar to mine of course, an HDMI cable, and a freshly installed Combined Community Codec Pack with Media Player Classic on top of which the newest FFDShow was installed. What from here? (I have a 7.1ch setup, all from the Onkyo HT-S6100 HTiB)

FYI, something relevant additionally might be that when/if I play AC3/DTS in MPC, checking under filters, basically just AC3Filter, and now for the purposes of testing FFDShow Audio, is the only thing that appears. With MP3 for instance though, what else appears is the MP3 Decoder DMO.

Thanks for not taking any of these disagreements overboard thus far and continually responding on more merit than simply your behalf.

[nurbs]

First check if your audio settings in Windows. Make sure that the right number of speakers is specified and that your sound card doesn't have any processing (DRC, equalizer, ect.) turned on.
Then go to the ffdshow audio configuration. All the filters should be unchecked. In the output settings all outputs but 16bit integer should be unchecked for the moment.
Deactivate AC3Filter for the moment.
Play an AC3 file and take note of what your receiver displays.
Activate AC3 pass through in ffdshow.
Play the same file again, note the receiver display again.
Post if you can hear a difference and what your receiver displayed in both cases here.