How do I convert LPCM to AC3 or Mpeg 1, Layer 2?

[LRD]

I have a Compro VideoMate Live USB 2, which hardware encodes only LPCM audio. Before I burn to DVD, I would like to convert the audio to a less memory intensive form, such as AC3 or Mpeg 1, Layer 2. I would like more space for video data. Are there some freeware tools that will do this? How are they used? I am about to spring for $128 of TMPGE products, but would like to consider the options beforehand. It was a lesson learned with DVD Shrink, a great free product.

Thanks

LRD

[johns0]

Use ffmeg with gui,it encodes wav or mp2 to ac3 and its freeware.Tmpgenc dvd author has a separate ac3 plugin you can buy that will encode your files to ac3.

[xtreemkareem]

Use HeadAC3he. It's free, easy to use, coverts to and from LPCM, AC3, MP2, MP3, Ogg(?) and does a decent quality job.

[awlchu]

LRD,

You don't need to spend $128US. Just buy the AC3 encoder and install it. After you register it, the AC3 option for encoding will be available.

$29US vs $128US no brainer really, the the encoder is qualified by Dolby for 2 channel encoding.

I have a Compro VideoMate Live USB 2, which hardware encodes only LPCM audio. Before I burn to DVD, I would like to convert the audio to a less memory intensive form, such as AC3 or Mpeg 1, Layer 2. I would like more space for video data. Are there some freeware tools that will do this? How are they used? I am about to spring for $128 of TMPGE products, but would like to consider the options beforehand. It was a lesson learned with DVD Shrink, a great free product.

Thanks

LRD

[LRD]

First, thanks all for the prompt help.

I tried ffmpeg, and performed the conversion without problem. I then used Tmpge Author (eval version) to do a short test. I used the video from my raw hardware encode and used the audio from my ffmpeg test. I cut the video in front to remove extraneous material and I cut the back to make the test short. I created a clip with audio about 1 sec out of sync. Can you tell me how to create a final copy, after front/back editing and chapters that has proper sync? My raw mpeg encodes always start a little early and end late, requiring clipping.

Thanks

LRD

PS Perfect Harley comment.

[muskgrave]

if you seperated the audio from the video before you cut the video then you will obviously have a sync problem when you join them back together..

just in case thats what you did you need to do the cutting THEN seperate the audio/video..clean up audio and join back during authoring.

dlv

[LRD]

Thanks Muskgrave. I will give your suggestion a shot.

LRD

[spectroelectro]

BeSweet. With the AC3Machine GUI. It's free, it's fast, it works every time. Spend nothing, get great results. Additional benefit: once you've installed the AC3 filters in DirectX you can encode any audio in your audio editing app into AC3 as well.

[LRD]

Dear Muskgrave

I don't know how to edit the video and then import the audio. If I edit with Tmpge Author, it creates dvd folders with LPCM audio. The created dvd folders cannot be used by ffmpeg, which wants pure mpeg. How do I merge the AC3 audio with the video BEFORE editing either to keep matters in sync?

Thanks

LRD

[muskgrave]

Okay..correct me if I'm wrong. Your first process is capturing with the hardware mpeg encoder correct? The very next step should be the trimming of the mpeg2 file. At this point the audio and video are still connected in the single mpeg2 file correct? So that being the case if you cut 1 second of video from the beginning of the file then you are also cutting the same 1 second of audio from the beginning of the file. THEN you can compress your audio to AC3 by whatever means you choose. I may be oversimplifying it but it seems like this is what is being done:

Capture > Seperate Audio > AC3 Compress > Trim Video > Re-Join Audio during authoring process.

When it SHOULD be

Capture > Trim Video/Audio > Seperate Audio > AC3 Compress > Re-Join Audio during authoring process.

dlv

[LRD]

Dear M

I understood the concept. My problem is that the program I use to do the audio/video trimming wants to output the finished product as dvd folders. When I attempt to use ffmpeg on the edited dvd folders created, it states it is an invalid format. It appears I need to edit in a program that will output in a format that ffmpeg recognizes. Is that Ulead MF outputing to a video file? What program would you recommend and what edited output should be generated that can be read by ffmpeg and later converted to dvd folders?

Thanks for your patience and continued help.

LRD

[LRD]

I may have found my own fix. Using Nero Vision Express in the 6 Ultra pack, I have found that a third party mpeg can be "exported" as an mpeg rendered as a 1 or 2 pass vbr. Using the custom setting, you can adjust resolution, bit rate and audio. In fact, it lets you convert LPCM audio to AC3. I do not yet see where it lets you adjust the sample rate of the audio. I am doing a test now. If it works, I may buy the product as a download upgrade to Nero 5.5. The cost would be $50; a good price for a video editor incorporating AC3.

LRD

[LRD]

I didn't fix my own problem. The Nero encodes AC3 audio, but with horrible sync problems.

LRD

[yepyep]

If the MP2 is out of sync, I do the vdub -> (uncompressed wav) -> ffmpeg / AC3Machine -> (ac3) method.

ffmpeg & AC3Machine might produce different results, so if one doesnt work I try the other. I might be mistaken in this as I just discovered that DVD Maestro often shows the wrong info for assets when first imported - closing and opening shows them correctly...

Note there are different versions of VDub...

VDub-MPEG2-AC3 1.5.4
Set audio to Full Processing Mode and Compression to PCM.
Save as WAV (huge file)

VirtualDub-Mod-ogm (streams)
Select Streams and save wav. Note that if you save an AC3 here it has a WAV

[yepyep]

OOPS...

VirtualDub-Mod-ogm (streams)
Select Streams and save wav. Note that if you save an AC3 here it has a WAV extention, is a small file, and it wont work. It does ogm.


[/i]