6.1 DTS > multichannel MP2

[Taric25]

Hello.
I posted the subject about how to convert AC3 to MP2 for SVCD and still be multichannel. The answer is to use SSRC to convert the AC3 from 48kHz to 44.1kHz and then transcode it to MP2 (MPEG-2 Tile Layer 2) for SVCD by using the AC3 > MP2 utility in ReMPEG.
Now I was wondering how to convert 6.1 DTS to multichannel MP2. My idea is that somehow the DTS could be converted to AC3 and then have that downsampled from 48kHz to 44.1kHz and then use the AC3 > MP2 utility in ReMPEG. The only problem I can see with this is that 6.1 AC3 might be impossible or extremely hard to support. If this is totally impossible, then I suppose that the DTS could be downmixed to 5.1 AC3 and then it could be converted to MP2 for SVCD. Any ideas?
I am using Windows 2000 Professional, a 550 MHz Pentium III with 128 MB of RAM.

[DSPguru]

SSRC is not an AC3 sample-rate convertor, it's a WAVE sample-rate convertor.

the idea of :
48Khz DTS -> 48Khz AC3 -> 48Khz WAV -> 44.1Khz WAV -> 44.1Khz AC3 -> MPEG MultiChannel
isn't a good idea, due to the loss of quality in every step in this chain, which might lead to poor quality on the overall.

i suggest you a better chain :
48Khz AC3/DTS -> (using a decoder)
48Khz MultiChannel WAV -> (using SSRC)
44.1Khz MultiChannel WAV -> (using modified version of rempeg)
MPEG MultiChannel.

as for this ReMpeg program, it tried to work with it and it crashed a few times :(

as for DTS decoder... any1 ??

[doom9]

no player plays mpeg multichannel so you can save yourself all the trouble. Well.. it plays the format but only in 2 channel mode.

[beergod]

doom9,

You are wrong. I have seen DVD player stream MPEG2 multichannel out hapilly. A lot of Sony's will do, and any surround decode that does MPEG multichannel will decode the streams. I have tried them on my machine .. it works.

The only thing is REMPEG had problems in encoding LFE channel. It makes the Left surround disspears.

sl --> gone
sr --> sl output
LFE --> sr output.

Duh ! anyone knows where to find a patched source code that fixes this problem ?

Beergod

[Doom9]

and since when does Sony support SVCDs? I know there are players that play mpeg2 multichannel, but that's on DVDs... and they will only give you 2 channels if you put an SVCD with the same audio format into the player... these are the facts my friend. My own player handles mpeg2 multichannel just fine when I put in a DVD that contains that audio format but that doesn't give you any info about how it reacts when the source is an SVCD.

[beergod]

Sorry, not sony, most C-Cube based DVD players plays SVCD, and mine certainly streams MPEG2 multichannel out successfully.

Any ideas how one can contact the author of REMPEG2, or author of MC MPEG2 encoder ?:)

[Newacey]

:)
I Have the Philips DVD 762 (this is the new one) and it plays MPEG-2 MC without any problems. You can even switch to downmixing mode.
I simply used the 48kHz AC3 and converted straight to an 48 kHz mpeg2-mc using ReMpeg and even that worked.

[beergod]

There is a bug in REMPEG2's MC MPEG2 audio transcoder. It is based on musicin which have the same bug ...

notice the right surround speakers contains the LFE channel, and the left surround speaker contains the right surround signals.
And Left surround signals have disappeared.

If you follow laddv's guide for making the MC MPEG2 stream, but don't do anyhting with the LFE channel, taking the -L option out, then it works nicely.

[Taric25]

Doom9,

You're a wonderful webmaster and an excellent source for information, but you have to be more optamistic. There are DVD players and recievers that support mutlichannel SVCD and DVD. Believe it. It's true. I have a MPEG-MC DVD player and it works just fine. I have had Dolby Pro-Logic sound on my DVD player and it worked just fine. I got 3, that's right, 3 channels of output. Other people here have also testified that MC-SVCD IS possible. Now I want to work on 5.1 SVCD and I seriousley don't like it when I try to start a conversation about it and you come in saying : Originally posted by Doom9 no player plays mpeg multichannel so you can save yourself all the trouble. Well.. it plays the format but only in 2 channel mode. In my opinion, you (or someone else) should write a guide on this and have it on your site for all to see. I don't mean to sound like a jerk, but I needed to get that out.

Everyone else,

I guess I need to take babysteps until I acchieve 6.1 MPEG-1 Tile Layer 2 audio for VCD (and also have it outputed correctly), but I think I'm on my way. Heck, DVDx would have never been created without Doom9's "20 tool meathod" :) . Any ideas for a better way to convert 5.1 AC3 to MC-MPEG? You can contact the ReMPEG author. How?:confused: Ask DSPGuru. I wouldn't know.:rolleyes:

[DSPguru]

hi Taric :)

unfortuntly, ReMpeg2 authors didn't reply my email. (or it just went to trash by one of my spam-mail-rulez... :(

anyway, if anyone gets his hand on any source code related to M2MC or even dll, let me know.. and taric's wish could be fulfilled :)

[Newacey]

If You need a SourceCode

try this page:

http://www.stud.uni-siegen.de/sven.koelsch/mpeg2mc/

If you can somehow compile a stable windows executable out of it. Please reply.

Greetings

[beergod]

I am seeking help on compiling a Win32 version of Musicin ... or even perhaps changing to code to make it accept wav files instead of AIFFs.

A couple of things needed to fix.

Anyone knows where to get multichannel wav2aiff ?

:o

[Newacey]

Try the link in my previous post.

The Tool is called PCM2AIFF (the modified version also accepts 5.1 wavs) there's also the source code of this tool.

[beergod]

Tried it, and compared the source code, it just added the support of an extra LFE channel ... but its still pmc2aiff .. not wav2aiff.

Thanks anyway

[Taric25]

Beergod,

I confused by something you typed.
Originally posted by beergod
but its still pmc2aiff .. not wav2aiff.
Is there a differance between pmc and pcm or was that just a typographical error?

Everyone,

Also, what's the differance between DTS, WAV, PCM, PCM DTS, and PCM WAV?

Also, what is everyone dressing as for Halloween? Here is what I shall look like. http://www.fansview.com/2001/animecentral/05112839.jpg I am the guy in the picture with the purple face.

[beergod]

Correction :

PCM, not PMC ... Sorry.

DTS is a lossy compression format used by movies and DVDs.

WAV is a sound file format mainly used by Microsoft installed PCs. It can is mainly used to store PCM audio. However, it can also be used to store some compressed format, but its rare.

PCM mean pulse code modulation, it uses code (eg. numbers) to represent audio waveform.

There is no such things as DTS PCM.

:)

[Taric25]

Beergod,

So, what's the differance betewwn PCM and WAV? Can't you use the program to do what you need? I found the directions on the page pretty simple. Yes, PCM DTS (not DTS PCM like you typed, spell check!) does exist. I have seen it. Where? I can't remember.

Everyone else,

Now that we have a bunch of source codes, should we mail them to Doom9 and have them put on his source page? I'm not a programmer, so is anyone up for making a multichannel 48kHz AC3 > multichannel 44.1kHz MP2 program? If possible, could the program be made to support MPEG-2 Tile Layer 2 and MPEG-1 Tile Layer 2? Should I move this to the development forum?

Ahhh. Bed time for me.

[Doom9]

@newacey: give me the source you used, tell me how you burned and I'll make a disc which I take to the store to see for myself.

[Newacey]

@doom9

Unfortunately I can’t remember the page I downloaded it from (all I know is that it was an ftp-site).
If you want to I could mail the file (ca. 10 megs) to you or at least part of it (or upload it somewhere).

I simply multiplexed this file with tmpegenc. Just take any SVCD-compliant video stream.
I took this muxed-file and burned it with Nero’s SVCD function.
And there it was.

The MC encoding also works with ReMpeg but the right surround channel will not work. But you can still hear the difference to normal 2ch sound.

If you are planning on going to a store, remember to switch the player to 6ch output, unless it will down mix the sound.

[beergod]

Doom9,

you can download it from here
http://www.labdv.com/en/examples/svcd_audio.php

WAV is a file format, PCM is a coding method for storing information. WAV can also have u-law ADPCM stored instead of PCM and othercoding method too.

Taric25, there is no much thing as PCM DTS or DTS PCM. I think you mean non-data marked CDs that carry DTS data stream.

[Doom9]

okay.. getting these files now. They're audio-only, right? I don't have a lot of time to test and a large timeframe to get to the store.. isn't there a done mpg file that I can just drag in nero and burn that works? I have other priorities than author SVCDs at the moment (hardware problems....).

[Newacey]

I'm not quite sure whether this stream works, didn't test it yet.
So don't wonder if the right surround channel is not working properly.

[Taric25]

Part 7 or the MPEG Doucument summarized in this MPEG-2 FAQ (http://bmrc.berkeley.edu/research/mpeg/faq/mpeg2-v38/faq_v38.html) states:
Non-Backwards Compatible Audio (NBC): addresses the need for a new syntax to efficiently de-correlate discrete mutlichannel surround sound audio. By contrast, MPEG-2 audio (13818-3) attempts to code the surround channels as an ancillary data to the MPEG-1 backwards-compatible Left and Right channels. This allows existing MPEG-1 decoders to parse and decode only the two primary channels while ignoring the side channels (parse to /dev/null). This is analogous to the Base Layer concept in MPEG-2 Scalable video ("decode the base layer, and hope the enhancement layer will be a fad that goes away."). NBC candidates included non-compatible syntax's such as Dolby AC-3. The final NBC document is not expected until 1996.
So, I think our "2 channel only" problem is caused because of MPEG-1 decoders since MPEG-2 audio is backwards compatible.

[Newacey]

Might be that you are right.

But since my player the philips dvd-762 has a built-in multichannel decoder, it might get the right info, which is to playback as well the surround and center channels.

That might explain, why it can playback all channels properly.

[Doom9]

again (and please respond fast).. I need a file that I can download and burn without considerably effort... only 17 more hours and my time window to test has run out for another 2 weeks... I really have no time to encode some stuff just for this test.. if you could put a 10mb file or whatever up somewhere (just email or pm me the link) that would be much appreciated.

[Newacey]

I'm going to send you a small testfile to your submission email-address.
Hope that you will receive it.

[Doom9]

I hope using the default mpeg2 directory is okay

[Newacey]

yes you can use either Mpeg2 or MpegAV (both will work).
WinDVD doesn't support SVCD with Mpeg2-MC Audio, neither does PowerDVD, but PowerDVD will at least show that it has found the 6 Audio Channels and then downmiax them.

[Doom9]

got the file, burned it, drove to the store.. and they had like 30 DVD players but no philips :( Anyways.. how about putting this file up somewhere so that everybody can test his player?

And does the player have an internal mp2m decoder?

[Newacey]

Well I'm Sorry that they didn't have a Philips-Player.

Concerning Your Question about the internal Decoder,
yes the Philips has an internal AC-3 and Mpeg-2 Decoder.
One can also download the Manual at the philips web-page.
Can't give you the exact URL, since it is under construction @ the moment.

Concerning the Uploading, I will see whether I can find the Source I downloaded it from.
Maybe I could email you the original 10megs-file and you can put it on your page, if that would be Okay with you?

[Doom9]

hm... we're talking a potentially large number of downloads here.. but I'll see what I can do... anybody up for some high bw hosting?

[Doom9]

could you upload the full 10mb clip somewhere and pm/email me the location... don't think my mailbox can take 10mb

[Taric25]

Doom9,

If you have 10 3.5 floppy disks, Newacey make a spanning archive of 10 1.0 MB files on disk, then e-mail them to you one at a time. You can then transfer the files to disk and unzip them.

[Doom9]

I don't even have a floppy drive anymore (unless you call a zip250 a floppy)... but you can rar em to split.

[Newacey]

What about IRC.
If you and me are online at the same time and you have an IRC-Client as well installed. I Could transfer this file directly to your computer.
But If you prefer the Multiple rar-Archives Way, I Cloud this too.

[Doom9]

I'm always on IRC ;) You know the net and channels (top of the link page)...

[Newacey]

The MultiChannel-Testfile has been sent to you.
It's called mc.mpa and contains only audio, but it works perfectly.

[Doom9]

yeah.. now I need somebody to host it.. if we do this right and mention it on other sites too we can compile a list of players that support the format and eventually look into writing a guide if it's worthwile

[beergod]

If you guys wanna go for it, I can help you write a guide for it as I have done it ... It does not require Soft encoder ... and its easier, and more effective. I have also done some quality comparison on downasampling using several tools.

What I need now is to contact the guy who wrote ReMPEG2 for the source code he compiled under Win32, and then make some changes to the code, andthen hopefully LFE channel will work. Currently, I managed to get make 5.1 AC£ --> 5.0 MPEG work beautifully.

[Newacey]

Well it would be great if you could tell us how you did it. DD5.1 -> Mpeg 5.0 is sometimes even better than mpeg 5.1, since due to the normalization the left an right channel my sometime start to clip. (I don't have a subwoofer, so the lfe channel will be mixed to left and right channel.)
Is it also possible to upload a small testfile somewhere so i can check whether its fully compliant and that also both surround channels work properly.

[Doom9]

just one thing about the file I have.. it's an mpa.. does that work if you burn it alone or do you have to add some dummy video track? As I have no hardware to test (and the DVD player in the house is about to die completely).. it has to be realy specific what people have to do with the file. I already got 2 hostings.. we can probably kick this off for good within 24h

[Newacey]

No You need a Video-Track. I don't have the video track which actually belongs to this audio-track, but, like you already suggested, just take any dummy-video-track. I didn't want to send you the file with a video-track, since it would have been around 50 megs and my upstream isn't so fast.
Just be careful not to take a video-track which has a higher bitrate than allowed and remember that the audio-track has 384kbs, so don't use more than 2.3 Mbps, just to be sure that the Player is playing the track smoothly.
I used TMpegEnc to muliplex the tracks and then I burned them with nero.

[beergod]

Newacey, give me your e-mail, and I will try to send it to you. Otherwise, give me an ftp site where I can upload the file to you.
The reason I did not do LFe is because of the bug. LFE is now mixed to L/R with -6dB. I also found problems with the enoder if signal is too large, therefore I tend to turn all the channels down 3dB

[Newacey]

My email-address is:
NewAcey@t-online.de

Would be great if you could email the file to me.
Please tell me as well which programs you have been using in order to create this file, and how you used them.

Thanx NewAcey

[Taric25]

Doom9,

If you don't want bandwidth to be taken up so much, why don't you instruct the people who upload/download the file to press reload before and after the upload/download of the file to save bandwidth. I know another webmaster who used this same stratgy for hosting MP3s. Also, what's wrong with my splitting idea, or do you already have the file via (m)IRC or e-mail?

P.S. The eleventh hour of the eleventh day of the eleventh month in 1918 is when armistice was called in WWI (World War 1). This marks Veteran's day in the United States, which was previously called armistice day. It is on this day that we remember the all the soldiers that were lost and all the veterans that still live today that have served my country. It is so ironic that it was two months ago that such a great tragedy occurred, and it only seems like last week to me.

[madluther]

Beergod, I've done some work on tools to convert AC3 to 5.1 mpeg2, ATM work is on hold but here's what i have so far

PCM2AIFF , ported to VC6, modified code to correct channel ordering, the original source puts the channel order as follows L,R,C,ls,rs,LFE. The encoder (musicin) expects the order to be L,R,C,LFE,ls,rs

musicin, ported to VC6, test streams produced sound good, mux and play back in windvd 3.0.

A direct show filter for mpeg2 5.1, Very early stages of development, currently has input pin buffer issues that i haven't had time to fix. the output pin and decoder sections are working.

If your interested email me and i'll send what i have.

Mad :)

[beergod]

Newacey,

I will try to remember to send you the clip tomorrow with documentation.

[beergod]

madluther

I would be very happy if you could send me the source code of musicin and pcm2aiff with some documentation if you can ... and perhaps the directshow filter ... I haven't any experience of directshow filter, but would love to get into it.

my e-mail is
beergod@yww1.freeserve.co.uk

I sent you an e-amil, I was wondering if you received it ...

Thanks

[madluther]

Beergod, yes i got your email, I'm at work now (I suppose I shouldn't be browsing doom9's forum at work, but the boss is away)

As soon as I get home I'll Rar the sources and send them to you.

Mad :)

[beergod]

Thanks madluther. I have been waiting for this day ...
I seek a friend's help to port the musicin code to VC6, but it just refused to create a compliant MPEG strem.