Muxers overdrive the muxed audio that will distort

[Bencuri]

I wonder if anyone has a solution for this:

I export the mpeg video from Vegas. I export the corresponding audio as .ac3 or anything else DVD compliant. I play the .ac3, it plays fine. I mux the video and audio (Imago Muxer, AVS2DVD, etc.), and the resulting mpeg will play with audio clipping. The volume becomes overdriven and distorts at some points (even on low volume settings). The only exception is Womble Mpeg Editor, that for some magical reason muxes the mpeg correctly, and the audio plays fine (even at max volume). Any other muxer overdrives the audio. What causes this? It is very annoying considering Womble is no more available, and I am just lucky I saved the installer before the site was shut down.

[Skiller]

Post a MediaInfo log of that AC3 please.

[Bencuri]

Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
File size : 27.1 MiB
Duration : 19 min 44 s
Overall bit rate mode : Constant
Overall bit rate : 192 kb/s

Audio
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Duration : 19 min 44 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 27.1 MiB (100%)
Service kind : Complete Main

[ProWo]

Mux it with clever Ffmpeg-GUI.
Load your video, click main. click multiplex, drag & drop the ac3 audiofile, select mpg as container, click multiplex.
Done

[Bencuri]

Not sure but it seems if the ac3 is exported by selection AGC ON, there is no distortion after muxing. If it is off, or rendered as wav and converted to ac3 during muxing, there is distortion. However that kind of file seems to boost the volume when the file starts and lowers later. Not sure but sounds a bit like that.

The other solution that seems to work is exporting in WAV from Vegas, and when converting to AC3 in AVStoDVD, selecting FFMPEG Safe Mode as conversion method.

[Skiller]

That's not the complete (advanced/detailed) log of MediaInfo where it would report if Dynamic Range Compression is applied and what value Dialog Normalization is set to.

I'm almost sure there is DRC and Dialog Normalization applied during playback because of improper encoding settings.

AC3 can be quite a pain in the butt. Since you are in PAL land, you can use MP2 audio for DVD, it's perfectly compliant and never causes issues like these.

[Bencuri]

That's not the complete (advanced/detailed) log of MediaInfo where it would report if Dynamic Range Compression is applied and what value Dialog Normalization is set to.

I'm almost sure there is DRC and Dialog Normalization applied during playback because of improper encoding settings.

AC3 can be quite a pain in the butt. Since you are in PAL land, you can use MP2 audio for DVD, it's perfectly compliant and never causes issues like these.

But how to get that kind of log?

The DVD is targeted for international use. Not worth the effort for MP2. But this way as I mentioned, with Safe Mode settings in AVStoDVD it seems to work. It would be good to know, however, why.

[Skiller]

But how to get that kind of log?

In MediaInfo you click on "Debug" -> "Advanced mode" and then "Debug" -> "Details - 10". The list will become much longer.

The DVD is targeted for international use. Not worth the effort for MP2.

You got this wrong. MP2 is the lowest effort you can have. Also it doesn't matter if it's an international or national release, it's a PAL disc, isn't it?

For MP2 you would just download the free TooLame and encode from a WAV file. MP2 doesn't have any DRC and Dialog Normalization. It's input volume = output volume. Simple. I use MP2 on DVD for anything that isn't 5.1 channels.