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Authoring multi-channel LPCM on DVD's

Discussion in 'High resolution audio' started by tireland, Jun 28, 2004.

  1. tireland

    tireland Member

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    Not quite on-topic but the motivation is to create HiRez multi-channel disks...

    I have been able to create HiRez (24/48) stereo audio tracks on DVD's using "DVD+Audio Creator" and Discwelder Bronze, but I would like to be able to create 4.1 24/48 LPCM audio-only DVD's for playback on any reasonably up-to-date DVD player. It seems like Wavelab5 and (perhaps) some version of Discwelder might enable this for DVD-Audio enabled players, but I would prefer to use the native DVD capability set. Are there any pieces of authoring software that will allow me to take 5 mono .wav files (or two stereo and one mono) and complie them into a single VOB file?

    Thanks,
    Tony
     
  2. wilkes

    wilkes Regular member

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    No.
    DVD-Video authoring packages will generally not allow multichannel PCM Audio.
    Admittedly it is in theory part of the specs, but your problem is the need to include some kind of graphical material in the content, as DVDV is video based.

    You need to stick with either WaveLab, or discwelder.
    The advantage to discWelder Chrome, despite it's hefty price tag, is the ability to automatically create a DVDV compatible layer for an unlinked hybrid that will play on all players.
    The downside with an unlinked hybrid is that it cannot of course be replicated. You can make your own copies though.

    For multichannel PCM audio only, VOB files are no use to you at all, as this is DVDV. You need DVDA.
     
  3. olk

    olk Member

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    I have authored (containing up to max.8) multichannel
    lpcms in 48khz to be playable on el-cheapo dvd-video
    devices.

    As wilke said, the drawback is that the vob files have
    to contain also at least a video stream of the duration
    of the audio lpcm, other wise you wont be able to cue and rewind, especially if the video part is too short
    You first have to mplex them into a mpeg, then author
    it to obtain the VIDEO_TS folder, containing all the
    ifo(s) and vob(s) then you make an isoimage for the
    dvd-r an burn it.You can decide between 48 or 96 khz
    and 16-20-24 bps and up to 8 channels. Another drawback
    is you can even use 44.1 or 32 khz or but the dvd-video
    players will play them at default at 48, which sounds
    pretty evil, quite pitched, but in your case, you have
    your material in 48khz ready, then it will work out of
    the box.

    Ah, perhaps i should have mentioned that i'm not on
    windows, what makes me perhaps an outsider, but hey
    it works pretty well, on linux.

    My actual problem is to put 44.1khz:2 chan:16 or 24 bit lpcm on dvd-r to be played from a dvd-video, but since those beasts ignore the content of the audio_ts folder,
    even being correctly authored as aob files, it seems to be a hopeless case (for me).

    Feel free to ask for details if you have access to
    linux box and want to get your lpcms onto dvd-r to be
    played from a dvd-video(only)


    good luck
    olk
     
  4. tireland

    tireland Member

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    olk,

    I would very much like to hear the details and would even put a Linux machine together if need be. If you would prefer to have this discussion via email, just let me know.

    Thanks,
    Tony
     
  5. olk

    olk Member

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    I have no problems talking here, well i dont know the
    policy if it is okay for everybody to spread oneselves
    here going into details or if it is just a question
    and answer style forum here, lol. If the others think
    that we are offtopic or talking about old stuff (well
    there was last year some kind of same discussion about
    analysing the structure of a dvd, regarding the
    contents of the video and audio_ts folders, what
    belongs to where and why and all that). I had to
    rewrite, we call it patching, some sourcecode of a
    couple of programs to suit my needs.

    To help you out, i will list a few programs you need
    to obtain a dvd-r or rw which can be played on every
    dvd-video machine.

    What you need:
    sox, mplex, dvdauthor, mkisofs, growifs

    Everything starts with an ordinary wav file.
    This is in little-endian format and has to be converted
    into big-endian, thats why we need sox.
    It transformes almost every audio format into
    everything. If you already do have lpcm, then you
    might skip this.

    Then we need a video of the duration of the lpcm,
    should not be too hard to create an mpeg containing
    only video but no sound.

    Next step is to multiplex the sound lpcm and the video
    into a big mpeg file. That is what 'mplex' does,

    Then you have to use dvdauthor, it creates a structure
    on harddisk like this:

    An empty audio_ts folder and the video_ts folder
    containg one or several vobs, if the length of the big
    mpeg was bigger than say 1Gb then vts_01_02.vob..03.vob
    etc are created automagically.

    Then you run dvdauthor once again with other params
    to finish the structure.

    Then you create a iso-image (dvd-image-file) which
    will be burned later on dvd-r(w).

    The whole process of all that takes a few minutes,
    i guess burning is the longest of all processes :)

    Now the syntax of all this, yah this is shell stuff,
    no clicky-pointy, sorry folks.

    1: Converting wav to lpcm
    sox <in.wav> -t raw -x -s -w -c2 -r48000 <out.lpcm>

    2: Aultiplexing audio and video into big-mpeg
    mplex -f 8 -S 0 -L 48000:2:16 -o <out.mpg> <vid.m2v>
    <in.lpcm>

    3. Authoring (creating the file structure from mpeg)
    dvdauthor -a pcm+16bps+2ch+48khz -c 0 big.mpg -o dest

    (dest is the toplevel folder where the audio and
    video_ts will be created)

    4. A 2nd necessairy Authoring subprocess
    dvdauthor -T -o dest

    5. Creating the dvd image
    mkisofs -dvd-video -udf dest > videodvd.iso

    6. Burn that sucker to dvd-r(w)
    growisofs -speed=0 -Z /dev/dvd=videodvd.iso

    Thats how it works for sure, you may change a few
    things for finetuning, like having this or that bits
    per sample for each channel separately.

    If you dont care too much about getting audible
    artefakts, to be honest i didnt notice any,
    you may upsample from 44.1 to 48 khz
    (what can be done with either sox or resample)
    to put some audio cd's onto dvd-video.

    Well, the sound gurus might kill us for that
    suggestion, but again, the algorithms used are those
    from Smith III, Julius O. and Phil Gossett
    'A Flexible Sampling-Rate Conversion Method'
    which are very well implemeted.

    All this sounds much more complicated as it really is,
    You just put all commands into one script, adjust the
    names and locations and you end up with a dvd-r to be
    used in every dvd-player, even from older generations

    Enjoy
    OLK
     
  6. wilkes

    wilkes Regular member

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    Plus the difficulty of finding a DVDV machine that plays back multichannel PCM with no trouble.
     
  7. tireland

    tireland Member

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    OLK,

    Thanks for the details. I have a couple of questions.

    First, an observation - When you said,

    "My actual problem is to put 44.1khz:2 chan:16 or 24 bit lpcm on dvd-r to be played from a dvd-video, but since those beasts ignore the content of the audio_ts folder,
    even being correctly authored as aob files, it seems to be a hopeless case (for me)."

    I assume this is a problem for you because something like "DVD+Audio Creator" is not available in Linux. What you describe above is exactly what this software does for Windoze folks.

    Now the questions:
    You say you start with an ordinary WAV file. If I want, for example, to have four channel simultaneous playback, does this mean I need to have a four channel WAV file? If so, what software do you use to create multi-channel WAV files? How is the mapping between the four embedded audio stream in the WAV file mapped to audio channels on the DVDV?

    If not, i.e. one uses two stereo channels, which piece of software does the multplexing of the two stereo channels to get a single four channel audio stream?

    As a BTW, if I can create a legal four channel WAV I will try throwing it at "DVD+Audio Creator" to see if it barfs - which I guess it will.

    Thanks,
    Tony
     
  8. wilkes

    wilkes Regular member

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    DVD+Audio creator has nothing to do with the Audio_TS folder, wether you are on Linux, Windoze, OSX or the moon.

    To correctly author an Audio_TS, and get the files multiplexed correctly requires DVD-A Authoring software. Period. DVD+Audio creator is not DVD-A Authoring software. It creates Video_TS folders, so the audio can be played on a DVD-Video machine.
    To play Audio_TS folders requires a DVD-Audio player.

    Now to mixing.
    Personally, I use a combination of Nuendo & discWelder Chrome. You mix your music in Surround, then export the multichannel WAV files, if in 24./96 5.1 you then have to MLP encode, then Author the DVD-A.

    Okay? You need a full surround mixing system, including 5 full range monitors, plus the authoring gear.
    _X_X_X_X_X_[small]www.opusproductions.com
    Digital Audio Specialists[/small]
     
    Last edited: Jun 30, 2004
  9. olk

    olk Member

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    @wilke,
    that was the briefest summary one could have made

    But i guess tireland wants to do all that above on the
    dvd-v side, not on dvd-a.
    (video_ts folder vs audio_ts folder) :)

    He can get everything done right on video_ts, which
    can be played on a dvd-v player, but i guess there have
    to be 6 analog outs, the dvd-v player does a correct
    mapping of multichan-lpcm's stored in video_ts,
    that is a problem for me, but good for tireland...

    But i dunno what will come out over spdif, imho the
    dvd-v player might downsample to plain stereo (2 chan)

    I'll give it a try an report later on.

    Nobody tried to patch the firmware to get rid of the
    forced 48khz or 96khz playing of lpcm's stored in
    video-ts ?

    I also assume that this was the reason to use the
    dvd+(plus)a proggie which operates on video_ts

    /* Anecdote_Mode +ON
    My gf advised me to get a dvd-a player and put
    everything into the audio_ts folder and end of
    discussion ... gives me more time for her - lol
    instead of trying how to fool a crippled dvd-v
    player just to play something what it cant do
    /* End


    later
    olk
     
  10. wilkes

    wilkes Regular member

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    Sorry about the excessive bluntness - I was getting ready to do something else & mind was elsewhere.

    Trouble with trying to use LPCM multichannel on a DVDV is that most of them just ain't up to it, and as you say are hobbled down to 16/48 IF they will actually do MC PCM, which most simply won't. You certainly will never get 24/96 MC down an SP-DIF, as it isn't designed to take the load, plus you sail over the DVDV audio bitrate limitations of 6.144 MB/sec. DVDA gives you 9.6 MB/sec, plus the option for MLP, decoders for which are built into every DVDA player, to get your 24/96 MC, which without MLP would use 13.something MB/sec. That's your big issue with MC on DVDV, bitrate. It just isn't there. Your GF is right - get a DVDA player, and with software like the new WaveLab, or discWelder, you can be making your own DVDA in no time at all. Stereo DVDA at 24/44.1, or even 24/48 still sounds better than CD-A, and if you get the gear there is always the MC option, but that gets very expensive, plus you will see less of the GF as you will be too busy converting your back catalogue into Surround. Believe me, I know.

    And then it really gets expensive.

     
  11. tireland

    tireland Member

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    OK - I'm satisfied that my initial inquiry has been addressed very well. Let me summarize my conclusions:

    1) Creating a DVDV with MC 24/48 audio, where the video has the heck compressed out of it such that the aggregate data rate is below the DVDV max limit (i.e. maybe 4 channels max) is POSSSIBLE, BUT on any given player the LPCM audio playback may be limited to 2 channels and/or 16/46 resolution.

    2) Creating a DVDA with MC 24/48 audio is only constrained by the aggregate data rate of the DVDA and, if that rate is not exceeded (e.g. 6ch * 24 bits * 48Khz < 9.6Mb/s), can be created relatively inexpensively(i.e. no MLP required), with something like Wavelab5.

    All of that said, with a good range of universal players on the market I am still motivated to create a four channel 24/48 DVDV if nothing else than as a test disk to evaluate new players.

    All in all, I've had a blast so far creating stereo 24/48 DVDV's using DVD+Audio Creator and DVDA's using Discwelder Bronze. When I'm ready to move my masters over to 5.1 24/96 DVDA's, I guess I'll seek the help from folks like Opus Productions.

    Thanks for all the advice so far
    Tony Ireland
     
  12. wilkes

    wilkes Regular member

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    Both assumptions are essentially correct sir, and I l look forward to helping out wherever possible,
    DVD-A Authoring does not need to be too expensive as long as you stay at 48KHz, or even 44.1KHz. I have still to be convinced by anyone of the benefit of using high samplerates, other than to impress record companies & clients.
    4 channel 24/96 is acually possible without MLP, so you could even find out for yourself, although how to do this without it ending up as a test of the converters you are playing the material through is utterly beyond me.

    Hoe to see you in DVD-A labd very soon. For a universal player, I can recommend the Pioneer DV565A, or 563 as it is known in USAland.
    There was a little bug between this player & waveLab, but is all fixed now.
     
  13. tireland

    tireland Member

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    Messers Wilkes et al,

    This thread sort of mixed hires and and positional audio in an adhoc manner. Does anyone know of a forum that has the same level of resident expertise in positional sound as this one does in hires?

    Thanks,
    Tony
     
  14. wilkes

    wilkes Regular member

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    You could always try http://forum.doom9.org/forumdisplay.php?s=&forumid=11

    Again, I don't know much about ambisonics. It's a serious gap in the knowledge, and I really must learn it at one point.
    The tools for encoding are freely available at www.ambisonic.net

    LOL.
    Anything about PCM, then I can help. Dolby Digital - not too shabby. DTS - so so.

    I just find that multichannel works better when discrete channels are used, and I can also do the LCRS encoding straight from the PCM files too.
    Matrixed Surround is better than no surround, but it gets very technical trying to do it the ambisonic way. Very "round the houses".
    _X_X_X_X_X_[small]www.opusproductions.com
    Digital Audio Specialists[/small]
     
    Last edited: Jul 1, 2004
  15. olk

    olk Member

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    Tireland you could try it the way round to find out
    where the forums and folks do reside, am sorry that i
    dont know any.Here's few examples of sound-modification
    and correction:

    # Digital crossover filters
    # Room equalisation
    # Cross-talk cancellation
    # Wavefield synthesis
    # Auralisation
    # Ambiophonics
    # Ambisonics

    My advice is to look out for (open)source projects
    dealing with the above topics and sneek into their
    homepages and documentation and i am pretty sure you
    will be guided straightforward to forums and mailing
    lists. The authors of those kinda software are quite
    talkitive and i guess just simply asking them via
    mail is the easiest way to go :)

    Try starting by this one
    (quite theoretic but comprehensive stuff)

    http://www.ludd.luth.se/~torger/brutefir.html

    It's like in real life,
    you get to know people through people


    Good luck out there
    olk
     
  16. vurbal

    vurbal Administrator Staff Member

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    I played around with that myself last year, and it's definitely worth trying out if you have the time. Unfortunately it was 1 too many time consuming hobbies for me, but the one disc I made (Supertramp - Breakfast In America) sounded incredible, even on my crappy, old surround system.
     
  17. tireland

    tireland Member

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    One final report...

    All of these are Windows tools...

    After much messing around I was able to create 4.0 and 5.1 LPCM audio on a DVDV as follows:

    Using Maven3D I created 4 channel and 6 channel wav files. Other programs will surely do this but Maven3D is a really cool program and was fun to use. Just _how_ the channels in the wav file end up being mapped into the LPCM is a bit of a mystery, but as you will see below it doesn't really matter.

    I pulled the wav files into separate projects in DVD Lab PRO - the only (Windows) DVD authoring program I could find that wouldn't barf on multi-channel wav files. It also has a nice feature that it allows you to create "audio only", compiled the DVDVs. I tried to burn them with Nero but Nero barfed on the audio so I ended up burning them with DVD Lab Pro, which worked fine.

    When I tried to play the disks on my universal Samsung HD841, the disks queued up fine and played but I just got random bleeps and bloops out of the speakers. When I tried to play the disks on my PC using WinDVD6 I got the same bleeps and bloops out of the 4.0 disk and the 5.1 disk would assign the channels differently every time I played back the disk.

    So much for multi-channel LPCM....

    Tony
     
  18. wilkes

    wilkes Regular member

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    Sir.
    At the risk of repeating myself, I have tried to point out on many occasions that multichannel PCM does not happen from DVD-V players through digital outputs. It is that simple. This is due in part to CP measures, and also in great part to bitrate issues, as you have a total of 6.144 MB/sec available for audio in DVDV players.
    DVD-V players require multichannel audio to be in Dolby Digital or DTS. MC LPCM is not normally an option with DVDV players. You would need to find one that has 6 analogue outputs for this to stand a prayer of working.

    For multichannel PCM playback, you need DVD-Audio, which is a totally different animal altogether. DVD-Audio is designed from the ground up for superior audio performance, and has a maximum bitrate of 9.6MB/sec. Even this is not sufficient for 24/96 playback, or 24/88.2 playback unless the audio is MLP encoded to reduce the bitrate. MLP is lossless, so you lose nothing. You didn't say what bitrate your files were at, but I can assume either 24/48 or 16/48?
    Another issue with DVDV players is that most will not play 24 bit audio either, but truncate to 16 bit instead.

    DVDA does work, but it is not cheap. It is getting cheaper, with the advent of discWelder Bronze at $99, and WaveLab 5 these days, but you will need a very accurate monitoring environment to get things right.
     
  19. tireland

    tireland Member

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    Sorry, I should have been more precise - both the Samsung HD841 and (via an 8 channel sound card) the PC have 6 channel _analogue_ outputs. What I wanted to point out was that even devices with 6 channel analogue outputs do not respond predictably to multi-channel LPCM (at 16/48 actually) originating from the VIDEO_TS directory.

    In short I am in complete agreement with your observations and that agreement is based on empirical results from fairly time-consuming but interesting set of tests.

    I really do hope that DVDA establishes itself as a viable format. I have hundreds of hours of historic recordings that I would like to release in that format but there needs to be a sufficient audience in order to do so. Time will tell.
     
  20. wilkes

    wilkes Regular member

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    Agreed and agreed again.
    I think that this is one of the reasons that DVD-A has not - so far - taken off properly. A lot of record companies are holding back somewhat whilst they see which of SACD/DVD-A goes the way of Betamax. I guess nobody wants to be left holding a potentially embarrassing meeting with their boards of directors trying to explain why they just blew n million dollars on an obsolete format.
    There are others, unfortunately. There have been some very positive steps lately with the advent of affordable authoring tools which is definitely going to raise awareness of the format. This is probably half the battle. Now that home users, and people like we get on these boards can create their own discs, the demand will rise for "official" material. At least, I hope it does!

    The other big stumbling block is ignorance in the actual stores. My local store still does not know what DVD-A is, and the local "currys no worries" store has never heard of it. I was told "but this one does Dolby Digital. That's DVD Audio isn't it?" And that from a so called salesman.

    Fortunately though, with more & more universal players coming through, more & more people have the option for DVDA & SACD, even if they don't realise it yet.

    Here's hoping, anyway.
     

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