Some AC3 Encoding Questions

[Xesdeeni]

I am authoring a DVD of a football game from a VHS tape. The primary soundtrack is the stereo sound from the television broadcast. I am also adding a secondary soundtrack that is from a mono radio broadcast of the same game. Both are slightly noisy from the tape and sound-card digitizer, and of course both have lots of background noise from the game and crowd.

1. What is a good bit rate for the stereo soundtrack? I know that 5.1 usually use about 384Kbps, so would 192Kbps be overkill?

2. What is a good bit rate for the secondary mono soundtrack? It contains more noise than the stereo one. Would 64Kbps be too low?

3. Will the amount of noise in these soundtracks mean I need a higher bit rate?

4. Is there any issue with a single-track soundtrack (e.g. some DVD players may only play it from one channel)?

5. Is there any limitation on the DVD spec that requires the two soundtracks to be the same format (1/2 track) or bit rate?

Xesdeeni

[Suzahara]

Originally posted by Xesdeeni
I am authoring a DVD of a football game from a VHS tape. The primary soundtrack is the stereo sound from the television broadcast. I am also adding a secondary soundtrack that is from a mono radio broadcast of the same game. Both are slightly noisy from the tape and sound-card digitizer, and of course both have lots of background noise from the game and crowd.

1. What is a good bit rate for the stereo soundtrack? I know that 5.1 usually use about 384Kbps, so would 192Kbps be overkill?

192 is just right, that's what dvd manufacturers use for their 2.0 streams.

2. What is a good bit rate for the secondary mono soundtrack? It contains more noise than the stereo one. Would 64Kbps be too low?

I'd guess that you'd want to use 96 - 128kbps.

3. Will the amount of noise in these soundtracks mean I need a higher bit rate?

Noise and bitrates don't affect each other much. Although a higher bitrate may help it, filtering of the audio will help it more.

4. Is there any issue with a single-track soundtrack (e.g. some DVD players may only play it from one channel)?

Some dvd players might do this, but more than likely, it won't.

5. Is there any limitation on the DVD spec that requires the two soundtracks to be the same format (1/2 track) or bit rate?

No, the bitrates don't have to be the same. 5.1 and 2.0 are mixed all the time and they have different bitrates and number of channels.