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DTS Encoding - 16 bit?

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So I’m helping HAL out with encoding some 5.1 DTS tracks for him (regular 1510kbps DTS, not DTS-HD MA or anything), and I keep running into something that may or may not be a problem.

Using eac3to with Surcode’s DTS encoder, or using Surcode on its own, when I input 16 bit PCM audio, I get a DTS output that MediaInfo claims is 24 bit. No matter how hard I try, I can’t seem to get a 16-bit end result.

So here’s question number one: How can I get 16-bit DTS output from 16-bit PCM input, either using Surcode/eac3to or another program?

But in Googling around to find the answer, I keep seeing multiple people over the years saying that bit depth isn’t actually a thing with (or at least, is irrelevant to) lossy audio codecs. So while MediaInfo is reporting 24 bit audio, it’s really not 24 bit because it’s lossy. But in a lot of these same discussions, I’m also seeing that regular DTS needs to be 16 bit for compatibility with some programs, so … I’m kind of lost.

So question number two: Does bit depth (24 or 16) actually matter when it comes to DTS encodes or not?

For reference, here’s the MediaInfo of my DTS output file (encoded directly in Surcode from six mono AIFF files):

General
Complete name : D:\97GOUTDTS\V2\ANHV2.dts
Format : DTS
Format/Info : Digital Theater Systems
File size : 1.30 GiB
Duration : 2 h 3 min
Overall bit rate mode : Constant
Overall bit rate : 1 510 kb/s

Audio
Format : DTS
Format/Info : Digital Theater Systems
Duration : 2 h 3 min
Bit rate mode : Constant
Bit rate : 1 510 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 93.750 FPS (512 SPF)
Bit depth : 24 bits
Compression mode : Lossy
Stream size : 1.30 GiB (100%)

ChainsawAsh disappears a lot - bkev

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 (Edited)

Do rips of commercial discs read as 16bit? Just curious. You may also want to look for a program called LeeAudBi.exe for a more detailed look at what is in the frame headers. My guess is that the Surcode and eac3to encoders just don’t set the necessary bit in the frame header to describe it as a 16bit source. This source lists the contents of the frame header, and shows that there are three bits describing the source audio bit depth.

https://wiki.multimedia.cx/index.php/DTS#Frame_format

My guess is that your encoders just leave it set to 000 or 111, one of which probably corresponds to 24-bit. This is a total guess though. Remember that this is just a description of the source bit depth. Your other sources are correct in saying that bit depth is not really relevant to lossy compression codecs. The decoding of the audio is not necessarily effected, except that some decoders may try to match the bit depth of the decoded output to that of the source.

other info here:

http://stnsoft.com/DVD/dtshdr.html

If I had some gum, I’d chew a hole into the sun…

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Interesting, thank you! The DTS encodes have been distributed and available for a bit now (they were for HAL’s GOUT-patched 1997 5.1 audio) and I haven’t heard any complaints yet, so I’m hopeful that they work just fine.

ChainsawAsh disappears a lot - bkev

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Yeah, lossy DTS is lossy, bitdepth is sorta irrelevant.

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Yep, that seems to be the consensus. HAL’s prequel trilogy V5 has been out for a bit with DTS audio tracks I encoded for him, and I haven’t seen talk of anyone having issues with the tracks, so I think my concerns were unfounded.

ChainsawAsh disappears a lot - bkev