No way to downmix dts to ProLogic-II CD audio?

[LigH]

Dear community,

currently, I see no way to simply decode and downmix Multichannel dts to Dolby ProLogic II encoded stereo for use on an audio CD:

For example, I'd like to try to use the BS_Downmix.dll plugin to convert dts audio directly to DPL-II encoded audio, like that:

azidts.exe -auto6ch -core( -input dts.dts -output dpl2.wav -2ch ) -plugin( -name BS_Downmix.dll -func *** )

But I don't want to miss the LFE. Unfortunately, LFE input is not yet supported by the BS_Downmix.dll plugin - the only currently supported functions were "NoLFE" and "NoLFE_Old".

Is anyone able to add LFE downmix support? I don't have a C compiler; I'm not even sure if it is at all that easy as to adapt the downmix matrix from Azid...

Furthermore, azidts does not support "-ota( -g #db )": It reports the peak volume, but the created WAV file is not amplified, but empty! Obviously, it does not understand pregain. And without normalization, the result is way too quiet.

A possible workarounds could be to create an intermediate AC3 (but the BeSweet.dll 1.5b23 uses wrong channel mappings, and the *SPECIAL* BeSweet.dll does not support AC3Enc "due to its suckness", althoug it was fixed long ago; unfortunately, DSPguru never released a current DLL version 1.5b29)

azidts.exe -auto6ch -core( -input dts.dts -output ac3.ac3 ) -ac3enc( -b 640 )
besweet.exe -core( -input ac3.ac3 -output dpl2.wav -2ch ) -ota( -norm 0.95 ) -azid( -d 2/0 -s dplii -L -3db ) -ssrc( --rate 44100 )

But I may combine all the parts that at least work, to build a quite strange chain of conversions: dts => 6 mono WAV => mux => AC3 => DPL-II

azidts.exe -auto6ch -core( -input dts.dts -output Ch_ -6ch )
{build mux.mux}
besweet.exe -core( -input mux.mux -output ac3.ac3 ) -ota( -norm 0.95 ) -ac3enc( -b 640 )
besweet.exe -core( -input ac3.ac3 -output dpl2.wav -2ch ) -ota( -norm 0.95 ) -azid( -d 2/0 -s dplii -L -3db ) -ssrc( --rate 44100 )

Not really efficient, but at lease effective... - so I wonder if anyone has better ideas.

[Kurtnoise]

Hi LigH,

Maybe with GraphEdit and AC3Filter (last version which enable dts decode). With this filter you can control the output channels and/or the downmix/upmix.

By example for the filters chain : Input.dts --> AC3Filter --> Wav Dest --> File Writer (Output.wav)

[E-Male]

is the a version of ssrc (or similar) for directshow, so it can be used in graphedit?

[Kurtnoise]

IIRC, with DS DSP filter (http://www.dsp-worx.de/?n=4) you can use some Winamp plugin. And there is of course a SSRC plugin (http://nunzioweb.com/sawgstuff/wa/out_ds_ssrc.zip) for winamp. So, it should work. :)

[E-Male]

i gotta have a look at that
THX a lot

[LigH]

Beyond my problems already mentioned, I even found out that the InterVideo decoder seems to always decode dts - or azidts always writes WAV headers - assuming that it was encoded with 48 kHz. This may be true for dts coming from DVDs. But it is not true for dts coming from dts-CDs (this results in a remarkable speedup...).

So it is probably better to check the foobar2000 plugin if it is able to decode to something useful. Or maybe I can grab some output from ffdshow, or AC3Filter (if I can find download links of those oh-so-secret betas).

P.S.: Oh, dtsdec 0.02 is still available... another light in the darkness.

[E-Male]

@LigH:
the dts reader for foobar seems best for DTS-CDs ATM

@Kurtnoise13:
the SSRC-plugin is an output plugin
so it doesn't work with DS-DSP

[Kurtnoise]

mmmh yeah...:( You're right.

@LigH : http://ac3filter.sourceforge.net/download/ac3filter_1_01a_rc5.exe

[E-Male]

it doesn't violate any rule (at least IMO)
but is it ok to post links to non-public test-versions?

[LigH]

Another user of the german board is trying a similar thing - with ffdshow. The result was a bit quiet, but it shall be possible to amplify the output...

[Kurtnoise]

The link for ac3filter is pretty old. It's not a test version or anything else. This version has been release in may 2004. ;)

[LigH]

Released? Not at http://sourceforge.net/projects/ac3filter - and that's the only place I'd call "official"! ;)

[Kurtnoise]

Well...make a search in AC3Filter thread. The link is still there. :D

[edit] http://forum.doom9.org/showthread.php?s=&threadid=76480&perpage=20&highlight=AC3filter&pagenumber=5

by Valex himself...

[E-Male]

ooops, sorry
missread the version

[planet1]

another "inefficient" idea ;) :

creating a DVD-Audio (16bit pcm @44.1kHz) - and let the DVD-A player handle the 2ch downmix when needed (downmix "method" should be set during authoring):

http://dvd-audio.sourceforge.net/


btw Case updated his dts-plugin to 0.1:

http://www.saunalahti.fi/cse/foobar2000.php

[planet1]

regarding the 5.1 DTS -> 2ch PCM "mixdown"

maybe foobar2000's "Convert 5.1 to stereo" DSP will produce a desirable result. Dont forget to mark "Use DSP" when diskwriting to PCM otherwise youll get a 6channel WAVE.


The advantage over the azidts.exe + windvd decoder filter "crap" is that the result wont be upsampled to 48kHz.

cya :cool:

[E-Male]

what about ffdshow?
it can read dts (even in wav), do sample arte conversion (if needed) and output wav
if it doesn't support dpl2 (haven't checkt) you must add a filter for that in the DS chain (i think ac3filter will do it)

[magicclue]

a guy (Tom Keller) in the german forum just posted a message with a working filter graph.

He used DTS/AC3 Source Filter from "guliverkli" as DTS input source and ffdshow to convert DTS to Dolby Pro Logic II in one step. According to him it works; only the volume Normalize function has a delay and as the result without normalization was a little silent he boosted the volume.

Although in german just have a look at the filter graph.
http://forum.gleitz.info/showpost.php?p=182747&postcount=55

[E-Male]

might need some finetuning dependign on the situation (dts-wav, 48khz dts, ...) but should work