MP2 and AC3

[billiam]

I don't understand the difference between the quality of an AC3 that of a MP2 file. I know that an AC3 allows more than 2 channels. If i had a stereo wav file, would it be best to convert it to MP2 or AC3.

[Bulten]

mp2 also allows more than 2 channels (MPEG 5.1).

If you had a stereo wav file, I would go for Dolby Digital, though I cannot prove technically that it is better. Still I think a DD file with a bitrate of 192k/sec will sound better than a mp2 file with a bitrate of 192k/sec.

[bugster]

Another issue is compatibility. NTSC DVD player MUST support AC3 audio, but not MP2 audio, the reverse is true of PAL players. Though most players will support both formats, it is not always the case.

[Cornucopia]

Nobody said the most important question--what the destination format is...

If DVD, then AC3 is the preferred, If (S)VCD, then mp2 is preferred.
All bets are off if you don't care about compatibility.

Scott

[bugster]

Nobody said the most important question--what the destination format is...

If DVD, then AC3 is the preferred, If (S)VCD, then mp2 is preferred.
All bets are off if you don't care about compatibility.

Scott

True, but as the only video format that supports AC3 AND Mp2 is DVD, I thought it a reasonable safe assumption that this was the format under discussion.

FYI, IF (S)VCD, mp2 is mandatory as it is the only supported audio format. X(S)VCD's with Ac3, Mp3, wav or other formats may work on some players, but not many.

AC3 is NOT mandatory on PAL region DVD players, though these days you will have difficulty finding one that doesn't support it.

[billiam]

I am making a NTSC Dvd. I am using mp2 atm, encoding it at 384 kps. Why is ac3 more prefered? Does it sound better?

[Cornucopia]

This has been mentioned before, but I'll hazard another time:

NTSC DVD Audio:
1 track must be Linear PCM or AC3
additional tracks may be those, or MP2, DTS, SDDS.

PAL DVD Audio (used to be):
1 track must be Linear PCM or MP2
additional tracks may be those, or AC3, DTS, SDDS.

Due to heavy lobbying by Dolby--PAL was revised in 1998(?) to:
1 track must be Linear PCM, AC3 or MP2
addional tracks may be those, or DTS, SDDS.

This is for "Strict" compatibility. Many players can do just fine if it's authored off-spec. But many players can't. On these, you won't get any sound.

Scott

And, yes, AC3 has been recognized by most people as sounding better than MP2 for the same bitrate

[billiam]

So should i use virtual dub to extract the sound as a wav, then use besweet to convert it to an AC3. In tmpgenc, only convert the video. How would i put the audio and video together then?

[bugster]

So should i use virtual dub to extract the sound as a wav, then use besweet to convert it to an AC3. In tmpgenc, only convert the video. How would i put the audio and video together then?

This depends on your authoring app.
1st, not all authoring apps accept Ac3 in ANY form.

If your authoring app requires the streams be multiplexed then use TmpGenc mpeg-tools simple multiplex to join the m2v and Ac3 files together. Ulead DVD WS requires them in this form.

If your authoring app accepts or requires primary streams, just leav them as is but make sure the filenames are the same and they are in the same folder.

i.e. you would have movie.m2v and movie.ac3. Spruce up requires them like this.

[billiam]

so besweet is the best app to use to convert it to an ac3?