'Popping' speakers

[koberulz]

I've got a DVD with a 5.1 ac3 file as the menu music. When it reaches the end of the track, a 'pop' can be heard from the speakers. This also happened to the main timeline of one disc, to the end of which I'd added a black image for one second.

Is this my speakers, or am I violating some sort of rule, or what?

[transporterfan]

If you cut the sound track you probably neglected to find the 'zero crossing' points first.

http://forum.audacityteam.org/viewtopic.php?f=12&t=59558

Edit: forgot to mention the DC offset problem too, but it's in the link above.

[koberulz]

Okay, so I opened it in Audacity, found the 'zero crossing' points, re-cut...and now it won't import into Encore. That sort of encoding apparently only supports two channels.

[transporterfan]

Go to Preferences > Import/Export and set 'Use custom mix'
Go to File > Export, then change “Format” to “AC3 Files (FFmpeg)”
Use Options on export window to set bitrate.
Leave channel settings (when you save) as default to save original configuration.

[koberulz]

Evidently the bitrate was the problem. Audacity was trying to export at 160, the original was 128. I set the export to 128, but now it sounds absolutely horrible. It's all 'warbly'.

[transporterfan]

That's a new one on me.
A slightly higher bitrate wont make any difference to the quality. It should sound the same.
Did you install the FFmpeg and Lame plugins from the Audacity site?
Did you test 'play' the file in Audacity before you exported: how does it sound on playback?

[koberulz]

The slightly higher bitrate was preventing import into Encore. The quality went to hell when I exported with the same bitrate. Or at least, the same bitrate reported by VLC. Which could be wrong.

It sounds fine in Audacity, though.

[transporterfan]

I think it's wrong. 128 is ridiculously low for a 5.1 mix. It would need to be 3 or 4 times that to get quality sound.
384 or 448 kbps would probably fix the sound distortion. As for Encore, can't help you there. Don't use it.

Also, did you trim your sound file equally in all channels? If one channel is longer than the other Encore may interpret it as corrupted. No offence, just making sure. Lol.

Edit: Use MediaInfo on the original file to see if it gives any better info.

[koberulz]

I didn't, because the zero points didn't match, but the 128 kbps one opens fine, so it's not that. MediaInfo has this to say about the original:
Format : MPEG Audio
File size : 567 KiB
Duration : 35s 928ms
Overall bit rate : 128 Kbps
Writing library : LAME3.98r

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Duration : 35s 928ms
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 561 KiB (99%)
Writing library : LAME3.98r

I exported at 384 kbps, and it works fine, though it is significantly louder for some reason.

[transporterfan]

Unless the metadata is completely whacked, that's not 5.1 sound.
It's 2 channel MP3, and it actually is 128 kbps.
Are you sure that's the original and not your first 2 channel export attempt?
By original I meant the file on the DVD...

[koberulz]

Ah. I've got two copies of it: a stereo mp3 and a 5.1 ac3. And, like an idiot, I've been opening the mp3 file to see what bitrate it is. The actual 5.1 ac3 is, indeed, 384 kbps and significantly louder than the mp3.

This is why you don't troubleshoot at three in the morning.

[transporterfan]

Lol. No problem. I think you know what you have to do. Good luck.