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Audio DVD-Video

 
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RMN
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PostPosted: Thu 9 Feb 2006, 0:21    Post subject: Audio DVD-Video Reply with quote

Technics wrote:
Do you have any knowledge relating to putting together an audio DVD? I don't mean DVD-A, but using a DVD to have just music.


Well, for DVD-A I'd refer you to our resident (or at least frequent Wink) expert Neil Wilkes.

As to audio-only video DVDs, there's no such thing. The video on a DVD might be black, but you still need to have at least one video stream. Black video is still video. Down with racism! Wink

Technics wrote:
One thing I noticed is for video it uses a jpeg, and seems to keep the bitrate on the video side very low, like around 10k! Since this, with the 1536k audio, is under 2000, do you think that might be way people are having playback problems? They're having trouble on all sorts of players, even the PS2.


I doubt it. The drive on the PS/2 does have problems with some types of media, but it should deal with any bitrate with no problems (it's essentially a "PC" drive, anyway). With older players, keeping it above 2000 might be a good idea (just check "enable padding", in the encoder).

It's possible that the software being used to create these "audio only" DVDs might be a bit dodgy, and creates DVDs that aren't quite standards compliant. I find that unlikely, but it's possible.

So, if you have any problems with DVDs created by that software, my advice would be to think of the "audio only" DVD as a regular video DVD (with black video, or a still image, or whatever - and a low bitrate, so it doesn't eat into your audio bitrate and doesn't take up too much space), and create it using your normal DVD creation tools.

If your authoring program lets you assemble multiple video streams, just create a few MPEG-2 files with nothing but black video (ex., one with 1 second, one with 10, and one with 60), and then assemble them on the timeline to match the length of each audio file. It's much faster than creating video files to match the length of each song.

Alternatively, make all songs into one big audio file, pair it with one big video file (same length, or built from pieces, as above), and set chapter marks at the beginning of each song.

You can also add the names of the songs (and any other info) to a subtitle track, or directly to the video streams.

Then make the menus, etc., just as you would with a "normal" video DVD.

Regarding the audio files themselves, if they come from audio CDs they'll be 44.1 kHz, and you'll have to convert them to 48 kHz for DVD. Personally I would do that in a "real" sound processing application (the guide you mentioned in the PM used TMPGEnc for the conversion).


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PostPosted: Thu 9 Feb 2006, 1:18    Post subject: Re: Audio DVD-Video Reply with quote

rmn wrote:
With older players, keeping it above 2000 might be a good idea (just check "enable padding", in the encoder).


So, keeping in mind the audio is 1536k, should I make the "video" have a minimum bitrate of 464? And since it is just a constant black video, I could just use CBR, right?

The program I was using was Goland's "Audio DVD Creator" http://www.audio-dvd-creator.com/ which supposedly takes care of all of this for you. The finished product was a bit dodgy, though, and I did everything I was supposed to do.
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PostPosted: Thu 9 Feb 2006, 2:21    Post subject: Reply with quote

I think I might have determined at least some of the problem when I used the above mentioned program. I think the video stream might have something like "one frame per GOP" or even "one frame per chapter." How exactly this is pulled off is beyond me, but it obviously causes problems for some people!
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RMN
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PostPosted: Thu 9 Feb 2006, 4:55    Post subject: Reply with quote

One frame per chapter would mean 25 chapters per second (PAL), so I think not. One frame per GOP is technically possible, but a very silly thing to do (wastes a lot of space with headers).

I'm not sure if the "2000 kb/s" safety margin is for the total bitrate or just for the video (I've never come across a player that actually had problems with low bitrates, those are just the recomendations of most high-end DVD authoring packages, like Maestro, Scenarist, etc., presumably based on some internal testing). If you want to play it safe, set the video to use 2 Mb/s.

CBR encodes faster so yes, use CBR.

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PostPosted: Thu 9 Feb 2006, 12:31    Post subject: Reply with quote

rmn wrote:
One frame per chapter would mean 25 chapters per second (PAL), so I think not.


No, I meant one frame per whole song, and actually I think that is what it is doing.
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RMN
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PostPosted: Thu 9 Feb 2006, 18:03    Post subject: Reply with quote

No, DVDs have to be 24, 25 or 29.97 frames per second (any other value won't be recognised by the player, and anything under 24 fps isn't even a valid MPEG-2 speed; it has to be faked by repeating frames). It also cannot be one keyframe per song, because there has to be at least one keyframe per GOP, and GOPs can't be any longer than 18 frames (NTSC) or 15 (PAL).

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PostPosted: Thu 9 Feb 2006, 21:33    Post subject: Reply with quote

I see. The software's description is confusing.

Quote:
Video Stream

Full stream
- Recommended to use with PCM mode.
- The most compatible video stream, should work with all DVD players.
- All player functions are enabled.
- Disadvantage: takes quite some space in the stream, therefor not really suitable for MP1 or MP2 mode.


One frame per GOP
- Recommended for use with MP1 or MP2 mode when 'one frame per song' does not work.
- Might not work on all DVD players, first test this mode with a rewritable disk.
- Fast forward and rewind functions will not work.
- Disadvantage: takes quite some space in the stream, but less then 'full stream' mode.


One frame per song
- Recommended for use with MP1 or MP2 mode.
- Might not work on all DVD players, first test this mode with a rewritable disk.
- Fast forward and rewind functions will not work.
- After stop and resume, the time on the DVD player display might not work until the next song.
- Advantage: does almost take no additional space in the stream.


So, can I use all "I" pictures, since for an audio DVD all I am doing is encoding a black still?
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RMN
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PostPosted: Fri 10 Feb 2006, 0:40    Post subject: Reply with quote

I'm guessing the "one frame per song" mode fills the GOPs with "empty" B-pictures (that simply tell the player to repeat the previous frame).

The same trick TMPGEnc uses to simulate frame rates below 24 fps (ex., 24 fps where every other frame is a "repeat" empty B-picture will appear to be 12 fps). That's not DVD-legal, though (I mean what Audio DVD Creator is doing - what TMPGEnc does is perfectly legal). Some players that support non-DVD MPEG files will play it, but it's risky, and seems like a really stupid way to save a few MB.

Yes you can use all I-pictures, or any combination you want. Since the image is black anyway, it's not like you'll notice any difference. Smile

If you decide to add something to the image (ex., song name, an icon, whatever), use I=1 B=14, for example.

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PostPosted: Sat 11 Feb 2006, 20:00    Post subject: Reply with quote

What would be the minimum settings I can use that would keep the video portion as small as possible, but still be very compatible with DVD players?
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RMN
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PostPosted: Mon 13 Feb 2006, 5:28    Post subject: Reply with quote

What do you mean by minimum settings? If the image is black, naturally, you can set the motion search algorithm to the fastest one, use CBR, 8-bit DCT, turn off scene detection, etc.. The size will always be determined by the bitrate. 2000 is generally considered as the "safe" value, but most modern DVD players shouldn't have any problem going below that.

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neil wilkes



Joined: 26 Dec 2003
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PostPosted: Tue 29 Aug 2006, 20:40    Post subject: Reply with quote

I don't know that particular package (DVD Audio Creator) at all, but it is very badly named. It sort of implies it does DVD-Audio, but all it does do is Audio on DVD-Video.

Moving onwards now I've been pedantic (sorry!)
I am guessing the Audio quality is the important issue for you here, as you are electing to use LPCM streams. This is good - what you really need is (IMHO) to use an application called DVD-Lab Pro, which has a special "Audio Only" title mode.

Before I give a full rundown though, can you please confirm that you definitely want to use uncompressed PCM audio?
There are definitely options available for you though, so all will be just fine.
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