The OFFICIAL word on audio support in TMPGEnc's DVD Author

[rlhartman]

I have had an email exchange with an employee of Pegasys Inc, publishers of TMPGEnc's DVD Author (TDA) and the commercial version of TMPGEnc's MPEG encoder, regarding the handling of audio and, specifically, AC3. Here is a cut-and-paste of the relevant content. (It would be nice to have this as a permanent record for the benefit of future site visitors, but I don't know how to do that yet - I'm new here myself.)

>>First Email Exchange<<

[I asked if TDA has any restrictions on elementary audio streams which can be associated with elementary M2V streams. Specifically, does TDA force a re-encode any audio formats to any others, like some other programs do.]

1) Theorically any kind of DVD-Video compliant audio source file can be
associated with a M2V file in TMPGEnc DVD Author. This includes LPCM,
MPEG-1 Layer II audio, Dolby Digital AC-3. When I say compliant, it
means it is at least stereo, TMPGEnc DVD Author includes its own
resampler/re-encoder.

[I asked if TDA's optional AC3 encoder could handle LPCM as input. The docs say MPEG Layer 2, but don't specifically say LPCM can serve as the input format.]

2) Yes, you can convert LPCM to AC-3 2.0 channel, it is pretty fast and
good at it. The same can be done with MPEG-1 Layer II audio track too.

>>Second email exchange<<

[I asked for clarification of answer #1 above. He mentioned TDA's "resampler/re-encoder" and I wanted to make darned certain it didn't force re-encodes.]

If the source file is compliant, and if the user him(her)self does not
change the audio output settings (see source settings window,track
setting button in the track list), the audio part is not re-encoded.
However, when there are different audio formats in one track, all the
audio formats are uniformized in one format in order to comply with the
DVD-Video standard).

[I apologized for being so specific in my questions, and pointed out that the docs don't explicitly answer the questions I was posing.]

The LPCM does not appears in the documentation because we though it was a "natural" feature. We provide a special option regarding NTSC because in Japan MPEG-1 Layer II is the "natural" audio format in DVD, AC-3 was mainly used in Europe and USA and is rather new here. I will ask for a better description page.

>>end of exchanges<<

This answers my questions, and pretty much guarantees I'll be buying TDA with the AC3 encoder. I hope this proves helpful to others as well.

[presto]

I'm curious about all the concern over audio. I never worry about audio and it always seems fine. I make my own DVD's using Tmpgenc DVD Author or I back up DVD's using DVD Shrink. I have no idea what format audio is in because it never seems to be an issue.

I'm just wondering if I SHOULD be more aware of audio issues or if it is only of concern to people doing more sophisticated DVD's (Maybe music or surround sound or something).

[rlhartman]

This thread originates from a discussion in another. Visit this to get caught up:

https://www.videohelp.com/forum/viewtopic.php?t=203005

As to why the audio format matters: I do simple stuff, too - mono and (at most) stereo audio. The reason I care about the audio format is because of the space it consumes. PCM has no compression and very high quality, but consumes lots of space. On a full or nearly full DVD, you can recover some of that space by encoding the audio in another, compressed format.

The resulting free space can be used as you wish... more video, higher video bitrate, etc. In my current project, I wanted to bump up the bitrate to improve the visual quality.

Scan the above-mentioned thread for more details.

[jaxxboss]

I also prefer the compressed audio so I can fit one extra 40 min tv show on my dvd and keep some video quality. What I dont understand is why encode in LPCM if you will just turn around and author it with ac3? Dont make sense really.

[rlhartman]

The *original* audio is often in PCM. Premiere captures DV from my camcorder, for example, and the audio is in PCM. That's where it starts. It's not an intermediate format, at least for me.