Is 'transcoding' the audio necessary?

[bvdd]

Hi all .. my first post!

I captured as MPEG2 with the audio track set at 48khz 16 bit Stereo. When I authored the disc (in Sonic MYDVD) it automatically started transcoding the audio track, even though it was already 48khz. This alone
took another hour.

Q#1: Is transcoding the audio totally necessary?
Q#2: If it's not, should I capture the audio with a different setting to avoid
it?
Q#3: Would different software beat the problem? (I'm not crazy about
Sonic MYDVD)

Thanks, great forum.
Bill

[wulf109]

You don't say what format the audio is,ac3,mpg,or pcm. MyDVD is notoriuos for converting audio to PCM. PCM audio is uncompressed and will turn a 100MB mpg/ac3 file into 700MB's.

[bvdd]

Well, you caught me with my newbie pants down .. I don't know what format the audio is. I assume you mean the audio format that was
"brought into" MYDVD for authoring, correct?

These were my steps:
1. Captured from VHS into ATI MMC software as MPEG2-DVD w/ 48kz 16 bit Stereo audio.
2. Start and end of the film were "trimmed off" using Womble software, which supposedly does NOT re-encode.
3. Authored in MYDVD.

So where do I look for the audio format?
Thanks

[borax]

Q#1: Is transcoding the audio totally necessary?
No, if your source audio is 48 kHz, it is totally unnecessary

Q#3: Would different software beat the problem?
Yes.

So where do I look for the audio format?
Use dvd authoring software, that determines if your audio is correct.

But also a lot of other programs can show you this info, like avicodec, gspot...
Have a look to the tools:
https://www.videohelp.com/tools?s=38#38

[bvdd]

Ok.
Since my originally captured audio is 48kz, it looks like either WOMBLE or MYDVD are changing my audio format and therefor requiring the final transcoding step.

[Shocker Milwaukee]

So where do I look for the audio format?

There should be a Preferences option somewhere that contains the audio encoding options available. Newer versions of SonicMyDVD allow both AC-3 and LPCM. If you're putting over an hour of video on your DVD, you might need to let it transcode the audio so your video will fit on a DVD.

[bvdd]

So where do I look for the audio format?

There should be a Preferences option somewhere that contains the audio encoding options available. Newer versions of SonicMyDVD allow both AC-3 and LPCM. If you're putting over an hour of video on your DVD, you might need to let it transcode the audio so your video will fit on a DVD.

Actually, I wanted 2 MPEG2 files on that one DVD. Each file was 1.8g and I'm burning to a 4.7g DVD .. so I assumed I had PLENTY of room.
However, as I said before, during the authoring in MYDVD transcoding was
'required'.

[Shocker Milwaukee]

Did it 'transcode' the video as well?

[bvdd]

Unless it transcoded the video without saying so, then no.
Only the audio with both files.

[ozymango]

2. Start and end of the film were "trimmed off" using Womble software, which supposedly does NOT re-encode.

Are you using Womble's MPEG Video Wizard or MPEG-VCR? If you're using Video Wizard, if you open a clip within the program and right-click on it, you can get the properties for the video file, including the audio streams.

Video Wizard can re-encode streams when you export, but doesn't have to -- if you trim and then export a clip, within the export options you can set what video and audio properties you want, and within the export window there are tabs for General, Video, Audio, and Monitor. On the Monitor tab there's a button for "Details"; click that and it'll show you the video and audio settings (and what parts are being re-encoded, if any).

You can check the Audio and Video tabs in the Export window to make sure the default settings are matched to your file type, so it doesn't accidently re-encode your video.

And if you're using mpeg-vcr ... well, it's not as visually friendly but there are also some properties tabs that can be set to change the video and audio, they may be set to the wrong defaults.

Hope that helps!

[Shocker Milwaukee]

Unless it transcoded the video without saying so, then no.
Only the audio with both files.

I did a test with my version of Sonic MyDVD (4.5?)

I fed it DVD compliant MPEG2.
It 'transcoded' audio only.

[bvdd]

Yup, same version.