24 bit or 16 bit audio to DVD?

[Leonie Reynolds]

Exporting now and hoping I've picked the right one... my footage originated on a Sony PAL HDV camera, 1080i/50. I'm exporting using 'current settings' and have picked 24 bit audio as that sounds like higher quality. Am I right? Heading for a deadline so would appreciate a heads-up if I've picked the wrong one... thanks!

[Mark Williams]

When I am doing a commercial project DVD master that is being used for replication I use AC3 audio at 320kb/s. This gives you more headroom for a higher video bitrate without a discernible drop in audio quality.

[Sareesh Sudhakaran]

Originally Posted by Leonie Reynolds

Exporting now and hoping I've picked the right one... my footage originated on a Sony PAL HDV camera, 1080i/50. I'm exporting using 'current settings' and have picked 24 bit audio as that sounds like higher quality. Am I right? Heading for a deadline so would appreciate a heads-up if I've picked the wrong one... thanks!

24-bit is excellent, but if you have recorded in 16-bit, say, then it won't sound better than 16-bit.

PAL DVD audio is 16-bit 44KHz at roughly 128kbps, compressed into the MPEG-2 stream. You are all right, but you don't need 24-bit.

[Leonie Reynolds]

Thanks! Good to know.

[Taky Cheung]

Found this info in wikipedia http://en.wikipedia.org/wiki/DVD-Video

The audio data on a DVD movie can be PCM, DTS, MPEG-1 Audio Layer II (MP2), or Dolby Digital (AC-3) format. In countries using the PAL system standard DVD-Video releases must contain at least one audio track using the PCM, MP2, or AC-3 format, and all standard PAL players must support all three of these formats. A similar standard exists in countries using the NTSC system, though with no requirement mandating the use of or support for the MP2 format. DTS audio is optional for all players, as DTS was not part of the initial draft standard and was added later; thus, many early players are unable to play DTS audio tracks. The vast majority of commercial DVD-Video releases today employ AC-3 audio.

The official allowed formats for the audio tracks on a DVD Video are:

PCM: 48 kHz or 96 kHz sampling rate, 16 bit or 24 bit Linear PCM, 2 to 6 channels, up to 6,144 kbit/s. N.B. 16-bit 48 kHz 8 channel PCM is allowed by the DVD-Video specification but is not well-supported by authoring applications or players.
AC-3: 48 kHz sampling rate, 1 to 5.1 (6) channels, up to 448 kbit/s
DTS: 48 kHz or 96 kHz sampling rate, 2 to 6.1 channels, Half Rate (768 kbit/s) or Full Rate (1,536 kbit/s)
MP2: 48 kHz sampling rate, 1 to 7.1 channels, up to 912 kbit/s

[Eric Olson]

Originally Posted by Leonie Reynolds

Exporting now and hoping I've picked the right one... my footage originated on a Sony PAL HDV camera, 1080i/50. I'm exporting using 'current settings' and have picked 24 bit audio as that sounds like higher quality. Am I right? Heading for a deadline so would appreciate a heads-up if I've picked the wrong one... thanks!

You have got it right. Even if the source is 16-bit, the audio should be be processed using 24-bits to reduce any audible effects of rounding errors during the mixing. When a 24-bit mix is exported as 16-bit, a dithering process is used to preserve the dynamic range. This works great for audio CDs. However, for a DVD with AC3 audio it is better to export as 24-bit without dithering and let the AC3 encoder perform all the quantization.

[Leonie Reynolds]

Thanks, didn't understand all of that but I get the gist!