Problems with multiple audio tracks in DVD Architect 2.0

[Barry Lajnwand]

I am having a bit of difficulty with a project I am working on. I authored a video a few days ago with DVDA 2.0 and it worked out fine on my PC and settop DVD players. I then added one audio track to the DVD and authored that compilation and am having trouble with the audio.

Both of the audio tracks are present. However, on my settop player, I must hit the "audio" button to get the audio tracks going from the chapter selection (whether by chapter selection menu's or hitting the "next chapter" button). I created one button each for the video to play with the two audio streams, and set it to play with the respective stream, and that works out fine. But when hitting the next chapter button the video plays without any audio (I can then manually get the audio to play, but neither audio stream plays automatically).

I tried it out on my PC DVD player and this problem does not occur. I also set each button in the chapter selection menu to play audio stream one (they were set to "no change") but this didn't help. Is there anything else I can do? Is it a compatibility issue?

Please help. Thanks in advance.

[Rob Lohman]

I'm assuming you have not had this problem on your settop
player before? What brand is it?

[Barry Lajnwand]

No, I have never had this problem before (but then again, this is the first time I have authored a DVD with more than one audio track). It is a Panasonic DVD-RV31.

[Rob Lohman]

I really don't have a clue as to what might be going on. The lack
of other responses seems to imply no-one else does either. The
best thing that you can probably try to do to narrow it down:

1) try as many other "real" DVD players with your disc. See how others react

2) try to burn the same project to another DVD brand recordable and see what that does

3) create a new project in DVDA and see how it reacts to multiple channels in that

It could just be a fluke for this one time. It could be your player
has a "problem" with such discs or it could be a problem with
DVDA. Doing more tests should help you narrow down where
the problem is. That's the best I can suggest, sorry.

[Peter Jefferson]

its teh player mate..

its nto reading the ifo corectly or fast enough..

i get this with an old XMS dvd player i have.. i usualy can throw anything at it and they play fine, but this player "skips" at the chapter points.. (looks and soundsa lil like a layer break) on anything authoried with DVDA..

[Barry Lajnwand]

I've run several tests.

1) Media doesn't seem to make a difference. Tried several different brands and all had the same results.

2) I tried using different video and audio files in DVDA 2.0 and experienced the same result when authoring with multiple tracks.

3) I tried DVDWS2 and experienced a whole new set of problems when using two tracks in this program (audio played fine, but it couldn't mux the audio + video well - the video was very choppy)

I think it may be a bitrate issue. When using multiple audio tracks, does the bitrate of all the audio tracks together count when calculating total bitrate for the DVD? Or does only one audio track count (as in the audio track being played at any one moment)? I suspect it is the former, in which case it would explain my difficulties. My video is encoded at 8000 kb/s and each audio stream was PCM, so the total bitrate would be 11072 kb/s (assuming my suspicion is correct), which is WAY above the legal specs for a DVD. If my suspicion is correct, I'm surprised it even played at all. If I am wrong about this, I'll have to run some tests on different settop players and see if that helps any.

[Rob Lohman]

No program will (should) allow you to go over the DVD spec and
in your case you are still below it.

You are 100% correct in that the TOTAL bitrate is what counts, so
that is:

• all angles (one video track is one angle)
• all audio tracks
• all subtitle tracks

So yes, you do need to add the two tracks to your video bitrate.
But, video can be a maximum of 9.8 mbps, but together with
everything I believe it is somewhere in the 11.* mbps range. So
you are very close, but still within the limit.

Personally I would not want to stretch the format to such a limit
with homemade DVD's. Others have said it should work fine, but
as you indicate, it is pushing it a bit.

Usually 2-pass VBR encoding at levels like 3000 - 5000 - 7000
should yield good enough results with a high quality encoder.
Then there is some room for audio as well.

Why do you not have your audio encoded as AC3? You get this
with the DVDA package and it will be much smaller in size. Also
I'm not that sure on how well some players can do PCM.

One last question: how do you listen to this audio track? Is it
from the DVD players directly to a set of speakers or does it go
through a receiver first? Might be a problem futher down the
audio pipeline as well.

[Barry Lajnwand]

I've heard other people mention (I think on the Canopus support forums) that DVDA 2.0 let them go over the DVD specs as well. I borrowed Pinnacle Impression Pro from a friend to see if it would allow the same project I authored in DVDA 2.0 and it didn't allow it, stating that the project had exceeded legal DVD parameters.

Rob, you are correct that max video bitrate is 9.8 mb/s, but max total bitrate is 10.08 mb/s. I did a quick calculation at http://www.videohelp.com/calc.htm and determined that my DVD was something like 1 mb/s over the limit (at least according to that calculator). I'm going to try encoding the audio to AC3 and see if that helps things.

I'm a stickler for getting as much quality as possible. I always encode at 8mb/s CBR and use PCM audio and have never had a problem with playback.

My settop DVD player is hooked directly up to my TV speakers.

Thanks for all the help. I'll let you know if encoding to AC3 did the trick.

[Barry Lajnwand]

On a side note, what bitrate does the DVDA 2.0 AC3 encoder encode at? Is there any way to customize the settings?

[Rob Lohman]

Barry: yes it does, but take a look at this thread

The DVD spec only allows for a slight variation in bitrates for
AC3 and I would stick with the commonly used ones.

Also, while you might like top notch quality as you call it at 8000
kbps CBR you really don't need to for a lot of times. That is why
VBR has been invented and it works so great. Especially at
multiple passes with a good encoder. Almost all commercial
discs are encoded with VBR because some scenes just warrant
more bits than others. You can always set your VBR to a max
of 8000 to have it available when needed.

The most crucial setting with VBR is the average rate since that
will determine the average quality of your movie as well. It always
looked good to me at 5000 kbps. Try it out and you might be
surprised. Anyway, I would go with AC3, a lot of people
can't here the difference (due to themselves or their audio set)
between PCM and AC3 anyway.

It is indeed 10.08, I was mixing some numbers up:

Maximum video bit rate is 9.8 Mbps. The "average" video bit rate is around 4 Mbps but depends entirely on the length, quality, amount of audio, etc. This is a 31:1 reduction from uncompressed 124 Mbps video source (or a 25:1 reduction from 100 Mbps film source). Raw channel data is read off the disc at a constant 26.16 Mbps. After 8/16 demodulation it's down to 13.08 Mbps. After error correction the user data stream goes into the track buffer at a constant 11.08 Mbps. The track buffer feeds system stream data out at a variable rate of up to 10.08 Mbps. After system overhead, the maximum rate of combined elementary streams (audio + video + subpicture) is 10.08. MPEG-1 video rate is limited to 1.856 Mbps with a typical rate of 1.15 Mbps.

Source: DVD FAQ chapter 3.4

[Yi Fong Yu]

i hate tooting my own horn but if this will help you then i don't mind =):

http://www.dvinfo.net/conf/showthrea...threadid=28496

in my experiences with ac3 in dvd arch 1&2 i have found that if you want to use vegas to output an ac3 file that dvd arch will approve and say that it is conforming to the standard without recompression then 16-bit, 448k 5.1 surround is pretty much the standard. as for anything else i haven't tried it. i would like to try 16-bit, 192k stereo since that is another STANDARD but i ain't too sure DVD arch will like it much. maybe it will i dunno.

i find it strange what DVD arch will or will not accept as ac3 files that are upto spec or not. if you watch open range kev costner's director commentary is ONLY in the center channel without bleeding and is ONLY dolby 1.0 in 96k! as DVD producers we should HAVE that option to do that if we desire since most DVD players is capable of that!

barry, as for uber-high quality, i know how you feel but unless you have hardware that CAN really record 24-bit audio or HD/film @uber high resolutions then setting bitrates that high really won't amount to anything. i have canon xl1s and i know the highest it records is 16-bit audio and miniDV @25Mbps. knowing that there would no point for me to set my DVD to include 24-bit/ 5.1 audio streams nor 9.xxMbps compressions. imho 9.xxMbps doesn't necessarily look better than 6 or 7max cause it's the limits of DV. now HD or film... that's another story altogether.