Space

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Level 1

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Space

My project so far is showing as 4.1Gb in the Disc Inspector and I was wondering how much an extra track with about 5 minutes of MPEG 2 and AIFF, and another with about 3 minutes, would take. That's all I need to complete the project.

If the answer is more than I have left in space terms, my next question involves Motion vs MPEG2 tracks. I could compile a few 1 minute videos in Motion and save that as a Motion file, then import that as an asset into a DVDSP menu as a background. Is a Motion file bigger per minute (a simple design, no animation) than doing it the usual MPEG/ track route?

Mac OS X (10.5.7), Mac Pro 8 core/ Apogee Rosetta 800

Posted on Mar 8, 2010 9:21 AM

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Answer 1

Mar 8, 2010 10:10 AM in response to jrm1

It is very important that you compress your AIFF files to AC3 files. This will save space on the disc, and more importantly reduce the bandwidth of your tracks.

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Answer 2

jrm1 Author

Level 1

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Mar 8, 2010 10:39 PM in response to jrm1

I'm a composer, and the reel is meant to showcase my music, so I'd rather keep the files as AIFF if I can. The MPEG 2 files far outweigh the audio in terms of size anyway. If I cut a scene out of one video piece, I'm sure the 'reclaim' in space would far exceed the amount gained by going AIFF to AAC.

Are there video compression settings in Compressor, perhaps, that would help...without degrading the image at all further. I'll post in the Compressor board.

But I would like to know if anyone has worked out the difference in file sizes per minute of video between Motion and MPEG 2/AIFF in a track in a menu.

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Answer 3

Mar 8, 2010 10:48 PM in response to jrm1

Thats not the point he was making. DVD has a bandwidth ceiling of roughly 10 mb/s (video and audio combined) Spiking over this or even coming close will cause playback issues on many players. First thing you need to do is calculate the correct bitrates with a bitrate calculator. Make sure to include uncompressed audio in your calculations. Then get a bitrate viewer and make sure your bitrates are low enough to accommodate the audio extras bandwidth taken up by aif audio.

http://www.signvideo.com/bt-rts.htm

http://www.google.com/search?client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial &channel=s&hl=en&source=hp&q=dvdbitrate+viewers&btnG=GoogleSearch

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Answer 4

jrm1 Author

Level 1

1 points

Mar 9, 2010 5:13 AM in response to Eric Pautsch1

Thanks for pointing that out, Eric. I'm new to this!

In the assets pane, I'm seeing the bit rates for each video and audio track. Approx 6.2mb/s video and 1.5Mb/s audio. Are they accurate? What I guess I'm asking is do I need another bitrate viewer (I know the answer is going to be 'yes!', but I need to know why always)?

I read your first link, and it was interesting.

The Motion assets I'm using don't show up as being big at all. Is there a reason for that?

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Answer 5

Mar 9, 2010 8:27 AM in response to jrm1

I'm a composer, and the reel is meant to showcase my music, so I'd rather keep the files as AIFF if I can. < </div>

Basic misunderstanding of DVD. The quality of the sound delivery system at playback will influence the listener's experience far more than the file format. Examine commercial-grade DVDs for their audio components. You will find they're almost all using AAC.

If you're releasing disks that you hope will lead to client contacts, you want to talk to other musicians and to locate their "how we made our DVD" blogs.

Hope you enjoy your adventure into DVD production.

bogiesan

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Answer 6

jrm1 Author

Level 1

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Mar 10, 2010 3:07 AM in response to David Bogie Chq-1

OK the, I'll convert to AAC if eberyone else does. That's good news.

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Answer 7

jrm1 Author

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Mar 10, 2010 3:07 AM in response to David Bogie Chq-1

OK then, I'll convert to AAC if everyone else does. That's good news.

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Answer 8

jrm1 Author

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Mar 10, 2010 3:11 AM in response to jrm1

In Compressor, the only AAC setting I can find is 128Kbps. Is that the best a man can get?

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Answer 9

jrm1 Author

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Mar 10, 2010 3:13 AM in response to jrm1

Ignore that last post. I see you can increase it. What's the optimum rate?

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Answer 10

Mar 10, 2010 6:50 AM in response to jrm1

David, surely you meant AC3 and not AAC?

In compressor, that would be under Dolby Digital.

Jeremy

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Answer 11

jrm1 Author

Level 1

1 points

Mar 10, 2010 7:05 AM in response to Jeremy Hansen

I was thinking the same thing - surely a Hollywood blockbuster doesn't release DVDs with sound files as small as an AAC.

Anyway the space saving is quite small AAC vs AIFF. In total I save 600Mb for duration of about 67 minutes of programme (excluding the Motion menus I'm using).

If the earlier post meant to refer to AC3 Dolby and not AAC, can one use the AC3 compression even though the original film did not have Dolby sound? Is it allowable (the Compressor manual seems to suggest it is) to use the AC3 setting on stereo audio?

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Answer 12

Mar 10, 2010 7:12 AM in response to jrm1

I don't understand what you mean by "allowable;" Dolby Digital (AC3) is a format that you can use to encode your audio. If you mean surround sound, then yes you can use AC3 for any number of channels.

You said that Hollywood must not release DVDS with audio that "small". Filesize is not a measure of quality. It is only an indication of quality if you are making a comparison between files of the same format.

Jeremy

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Answer 13

jrm1 Author

Level 1

1 points

Mar 10, 2010 9:09 AM in response to Jeremy Hansen

I'm a musician, so please allow for my assumptions, which are based on AIFFs vs mp3s and AACs. There the AIFF has far more detail than the best mp3 and its file size is also larger.

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Answer 14

Mar 10, 2010 10:40 AM in response to jrm1

There's no reason not to use Aif audio on this disc. Just make sure you overall bitrate settings are correct. If I were a musician, I would insist on uncompressed audio on my DVD. The only reason Hollywood uses AC3 is because they rather save bandwidth for video. I dont blame them since most dont care about audio nor have the systems to support it. Most concert discs have uncompressed audio.

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Answer 15

Mar 10, 2010 12:58 PM in response to jrm1

I agree and disagree with Eric. If you keep your overall bitrate, you are more likely to be fine. But as the bitrate goes up, some players have problems sooner if the audio is PCM. In other words, there shouldn't be a problem but sometimes there is.

Also, I think that AC3 sounds great; compared to CD (44.1/16bit) a 448kbps audio file is great, and cuts the audio bitrate by two thirds. I don't say that lightly; I am a career musician.

Now, if you are serious about quality, then you could record in 96/24bit. In that case I would use PCM audio. But I think that the quality difference between 44.1/16 and high-bitrate AC3 is small.

As an afterthought, what is the source of your audio? Are these Sibelius midi files, live recordings, DSP stuff?

Message was edited by: Jeremy Hansen

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