FLAC vs HD audio questions

[Karkas]

I tried searching google and here, but can't seem to shake the needle out of the search result haystack.:search:

Can someone explain or point me to where FLAC is compared and contrasted with DD-TrueHD & DTS-HDMA. I understand they are all lossless, but I assume FLAC is inferior in some way?

Thanks in advance, and I apologize if this is a stupid/common question.

Thanks

[Inspector.Gadget]

I understand they are all lossless, but I assume FLAC is inferior in some way?

Lossless is lossless. A sample encoded to DTS-HD MA, TrueHD, FLAC, ALAC, WAVPack Lossless, etc. will sound exactly the same on decoding.

[Atak_Snajpera]

FLAC has better compression versus TrueHD and probably DTS-HD as well

[tetsuo55]

FLAC has better compression versus TrueHD and probably DTS-HD as wellHow much better do you guestimate ??

Do you think it would be worth converting to flac container purely for the MB's?

[Karkas]

Thanks for the responses guys.

I figured the output would be the same since they are all supposed to be "lossless."

What about bitrates? all 7.1 channel support? What about cable (FLAC limited in some way over spdif like HD audio).

If FLAC has better compression than the non-free options why are the paid ones used at all?

[Blue_MiSfit]

If FLAC has better compression than the non-free options why are the paid ones used at all?


Because Dolby and whoever owns DTS spend lots of money marketing their standards, and these standards are part of the BluRay spec, whereas FLAC is just an open standard with little to no hardware support.

~MiSfit

[880]

Do you think it would be worth converting to flac container purely for the MB's?

I think it is worth it for the freedom, but is it possible?

[TinTime]

FLAC has better compression versus TrueHD and probably DTS-HD as well
Yeah, DTS-HD has the inefficiency of its core / extension structure so FLAC should out-compress it every time (at best compression). It certainly should for 16 bit DTS-HD MA with a 1.5 Mbit/s core.

How much better do you guestimate ??
This really depends on the source bitdepth and number of channels. An extreme example is 16 bit, 2 channel DTS-HD MA, which would compress a lot with FLAC, down to perhaps less than half of the original size. With 24 bit 5.1 or 7.1 I've found there isn't always much of a saving - maybe 10% or so. I haven't yet found a lossless audio track though that's bigger as FLAC than whatever it was originally.

What about bitrates? all 7.1 channel support? What about cable (FLAC limited in some way over spdif like HD audio).
FLAC supports eight channels and any sample rate. Actually there is a maximum sample rate but I forget what it is - it's really high. FLAC is limited in the sense that you can't transmit it over S/PDIF. So it has to be decoded at source and then only stereo PCM can get sent over S/PDIF. It also can't be sent over HDMI but of course it can be decoded and all channels sent as PCM.

[Karkas]

Because Dolby and whoever owns DTS spend lots of money marketing their standards, and these standards are part of the BluRay spec, whereas FLAC is just an open standard with little to no hardware support.

~MiSfit

But that doesn't make any sense. While I could expect consumers to be duped into paying for TrueHD or HDMA over free FLAC; I can't imagine publicly traded companies like Sony (Blu Ray) or Toshiba & co. (HD-DVD) to be cutting into their bottom line by paying to adopt inferior or even equivalent codec support.

Correct me if I am wrong, but I thought TrueHD & HDMA are not mandatory part of the specs for BR & formerly HD-DVD.

[Karkas]

It also can't be sent over HDMI but of course it can be decoded and all channels sent as PCM.

HDMI can carry PCM, but NOT FLAC? If your player can not decode FLAC it can not pass it along to the reciever to decode??

[TinTime]

But that doesn't make any sense. While I could expect consumers to be duped into paying for TrueHD or HDMA over free FLAC; I can't imagine publicly traded companies like Sony (Blu Ray) or Toshiba & co. (HD-DVD) to be cutting into their bottom line by paying to adopt inferior or even equivalent codec support.

Correct me if I am wrong, but I thought TrueHD & HDMA are not mandatory part of the specs for BR & formerly HD-DVD.

No they're not mandatory for blu-ray, but Dolby Digital and DTS are. So blu-ray authors are already doing Dolby Digital or DTS encoding anyway. TrueHD and DTS-MA are only inferior to FLAC in terms of compression, and often by not very much. I think that DTS-HD is superior to FLAC for blu-ray because of its backwards compatiblity with older hardware. Same with the pairing of TrueHD and DD. LPCM is always freely available for lossless, although the bitrate's a bit of a killer for multiple LPCM tracks.

Maybe FLAC will get used in the future though? I suspect it's lack of backwards compatibility ruled it out this time, if it was ever considered. I don't know how long it had been around when the new HD formats were being decided on. Maybe it wasn't mature enough.

HDMI can carry PCM, but NOT FLAC? If your player can not decode FLAC it can not pass it along to the reciever to decode??

There's no hardware support for FLAC in the home cinema area. At least none that I know of. So even if you could coax your player to pass FLAC out over HDMI, or S/PDIF for that matter, there aren't any decoders available to plug in at the other end.

[880]

HDMI can carry PCM, but NOT FLAC? If your player can not decode FLAC it can not pass it along to the reciever to decode??
There is no standard way of putting a FLAC stream on HDMI or SPDIF. Even if you could output FLAC, what receiver can decode it?
But that doesn't make any sense. While I could expect consumers to be duped into paying for TrueHD or HDMA over free FLAC; I can't imagine publicly traded companies like Sony (Blu Ray) or Toshiba & co. (HD-DVD) to be cutting into their bottom line by paying to adopt inferior or even equivalent codec support.

Correct me if I am wrong, but I thought TrueHD & HDMA are not mandatory part of the specs for BR & formerly HD-DVD.

Choosing Dolby and DTS makes sense. Blu-ray manufacturers already have to license the core formats, the studios do not have to produce a soundtrack in yet another format, and consumers get lossless tracks that are backwards compatible with the equipment they own.

[880]

I haven't yet found a lossless audio track though that's bigger as FLAC than whatever it was originally.

I did not know it was possible to transcode. :eek:

[TinTime]

I did not know it was possible to transcode. :eek:

eac3to (http://forum.doom9.org/showpost.php?p=1004685&postcount=1) :)

[jruggle]

This really depends on the source bitdepth and number of channels. An extreme example is 16 bit, 2 channel DTS-HD MA, which would compress a lot with FLAC, down to perhaps less than half of the original size. With 24 bit 5.1 or 7.1 I've found there isn't always much of a saving - maybe 10% or so.
TrueHD should be able to give good compression with 5.1 content. It has more complex channel weighting matrixes that allow for better decorrelation. FLAC only does this for stereo, and even that is more simplistic. Also, TrueHD has smaller latency, better error recovery, and more error resilience, which makes it better-suited to broadcast transmission and for storage on fragile media.

That said, it sucks that they decided to use proprietary audio codecs. I'm glad there are people out there who enjoy reverse-engineering. :)

[Karkas]

Choosing Dolby and DTS makes sense. Blu-ray manufacturers already have to license the core formats, the studios do not have to produce a soundtrack in yet another format, and consumers get lossless tracks that are backwards compatible with the equipment they own.

Good point. That actually makes sense.

Thanks!:helpful:

[sN1b]

How much better do you guestimate ??

Do you think it would be worth converting to flac container purely for the MB's?

On this 100 minute movie i just checked out:

DTS-MA: 1.97GB
TrueHD+AC3: 2.2GB
flac: 1.3GB

[tetsuo55]

On this 100 minute movie i just checked out:

DTS-MA: 1.97GB
TrueHD+AC3: 2.2GB
flac: 1.3GBFor that sample the difference is huge!! 5.1 or 7.1 audio?

[TinTime]

For that sample the difference is huge!! 5.1 or 7.1 audio?

...and was it 16 or 24 bit?

Here's an example I've just done. Source is 24 bit 5.1 DTS-HD MA, 1:36:56 long.

Source 2.73GB
FLAC 2.35GB

So a 14% saving converting to FLAC.

Converting a 24 bit source to 16 bit FLAC offers really big space savings, although it's not lossless obviously. Good enough for me though - I can't tell the difference. In this case the above audio can be reduced to a 0.88GB 16 bit FLAC track, making it a third of its original size. In fact it's smaller than the DTS core (1.02GB).

[Karkas]

Wow, I had no idea FLAC produced such good compression when compared to the big name lossless ones.

[SeeMoreDigital]

HDMI can carry PCM, but NOT FLAC? If your player can not decode FLAC it can not pass it along to the reciever to decode??Indeed....

Fortunately, we are now starting to see hardware players that can convert multi-channel FLAC streams (as well as Vorbis, WMA and AAC) to multi-channel PCM streams. The PCM streams can then be passed via HDMI to a suitably equipped surround sound amplifier :)

[rica]

Wow, I had no idea FLAC produced such good compression when compared to the big name lossless ones.

Just think lossless is like a zipped file.
When you unzip you get the the same as is.
I'd recommend you to listen audio in flac form with an HTPC using foobar (audio only) or reclock (video+audio).

[Atak_Snajpera]

FLAC has better compression versus TrueHD and probably DTS-HD as well

Source: Movie ButterFly on a wheel 1:34:52 48Khz 16 bit 5.1 (decoded by eac3to + ArcSoft DTS Decoder)



wave64 - size 3.05 GB
DTS-MA - size 1.23 GB
FLAC - size 693 MB !!!



Any questions? :)

[880]

By the way, how do we know the Arcsoft decoder truly outputs lossless?

[Atak_Snajpera]

eac3to will show youn warning if arcsoft decoder is not used during decoding dts-ma

[Thunderbolt8]

flac compresses very good for 16-bit files, but only little better at 24-bit, compared to the source. anything higher than 24-bit 48kHz mostly results in even larger file sizes as the original compressed track.

[880]

eac3to will show youn warning if arcsoft decoder is not used during decoding dts-ma

But how do I know ArcSoft does it right? For example, how do I know ArcSoft is not taking the lossy core and decoding it?

[Atak_Snajpera]

I does it right ,trust me. It was well tested by guys in eac3to thread.

[Midzuki]

By the way, how do we know the Arcsoft decoder truly outputs lossless?

By comparing the result with the output generated by the DTS Streamplayer. :devil:

I does it right ,trust me. It was well tested by guys in eac3to thread.

NOT tested on any .DTSMA file with less than 5.1 channels and
"core bitrate < 754kbps", I suppose. :devil: :devil: :devil:

[bmcelvan]

I've been converting my movie files with HD codecs (TrueHD and DTSHDMA) to flac and want to verify the channel maps are correct. I've noticed when analyzing FLAC files with mediainfo, it simply says:

Channel(s) : 8 channels
Sampling rate : 48.0 KHz
Bit depth : 16 bits

Where the other codecs seem to have mapped channels:

Channel(s) : 8 channels / 6 channels
Channel positions : Front: L C R, Side: L R, Back: L R, LFE / Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 24 bits

Is there a way to confirm the FLAC channels are mapped properly. I'm assuming that eac3to is doing it properly but is there a way to check?

Thanks

[Ghitulescu]

But that doesn't make any sense. While I could expect consumers to be duped into paying for TrueHD or HDMA over free FLAC; I can't imagine publicly traded companies like Sony (Blu Ray) or Toshiba & co. (HD-DVD) to be cutting into their bottom line by paying to adopt inferior or even equivalent codec support.

Correct me if I am wrong, but I thought TrueHD & HDMA are not mandatory part of the specs for BR & formerly HD-DVD.

1. You don't know ANYTHING about corporate level thinking.
2. BR specs are evolving, but I am sure HD audio was part of the specs since day 1.

[foxyshadis]

Heh, that was quite a few years ago, Ghitulescu.

bmcelvan, use eac3to to check, it'll give you all the correct channel information when MediaInfo doesn't. If you use eac3to to convert, you're gold.

[tebasuna51]

...Is there a way to confirm the FLAC channels are mapped properly. I'm assuming that eac3to is doing it properly but is there a way to check?

Now FLAC only have one channel assignement for 8 channels:
https://xiph.org/flac/format.html
Channel assignment

0000-0111 : (number of independent channels)-1. Where defined, the channel order follows SMPTE/ITU-R recommendations. The assignments are as follows:
1 channel: mono
2 channels: left, right
3 channels: left, right, center
4 channels: front left, front right, back left, back right
5 channels: front left, front right, front center, back/surround left, back/surround right
6 channels: front left, front right, front center, LFE, back/surround left, back/surround right
7 channels: front left, front right, front center, LFE, back center, side left, side right
8 channels: front left, front right, front center, LFE, back left, back right, side left, side right
1000 : left/side stereo: channel 0 is the left channel, channel 1 is the side(difference) channel
1001 : right/side stereo: channel 0 is the side(difference) channel, channel 1 is the right channel
1010 : mid/side stereo: channel 0 is the mid(average) channel, channel 1 is the side(difference) channel
1011-1111 : reserved

And eac3to was checked already (by me and others) and work fine.

If you want to check yourself make/obtain a Channels-test like this http://www.jensign.com/bdp95/7dot1voiced/ and make your encoded/recoded files.