Convert video with ac3 to mp3

[avillabon]

Hello everyone!

I have a divx 5 encoded video file (avi) with ac3 sound and i need to convert it to MP3 CBR so it can play in my portable media player which is compatible with divx 5 but not with ac3.

I always use AutoGK when i hae video codec problems but in this case the video codec is fine but the sound codec is not, which would mean that it would re-encode the video file resulting in quality loss.

All i need is to convert just the sound, is that possible? or do i have to re-enconde the whole thing?

thanks

Alex.

[redwudz]

You could use VirtualDub Mod and just convert the audio to MP3 and 'Direct stream copy' the video. That should go fairly fast. Then you will have the original video with MP3 audio.

You may need: AC3 ACM Decompressor and maybe Lame MP3

[drewzor]

*//edit

[avillabon]

thanks ill try it right now and post in a few minutes

[avillabon]

You could use VirtualDub Mod and just convert the audio to MP3 and 'Direct stream copy' the video. That should go fairly fast. Then you will have the original video with MP3 audio.

You may need: AC3 ACM Decompressor and maybe Lame MP3

ok i was going to try thinking it would be user friendly as AutoGK but now i notice it is not that simple.. Would someone refer me to a tutorial or take the time to explain step by step what i have to do... i cant seem to find a guide for it here in videohelp

thanks.

Alex.

[avillabon]

Sorry... in my previous post i mean to quote this "You could use VirtualDub Mod and just convert the audio to MP3 and 'Direct stream copy' the video. That should go fairly fast. Then you will have the original video with MP3 audio.

You may need: AC3 ACM Decompressor and maybe Lame MP3 "

[drewzor]

*//edit

[avillabon]

ok i got everything down... the only problem when i am using belight is that out of the total time in the wav file, it only encodes like 6 mins when the total length is around 100 mins. Is there a setting i am missing?

[avillabon]

which are other good wav to mp3 convertrs?

[drewzor]

*//edit

[avillabon]

Ok. I demuxed the auido so i get a "*.ac3" file. I play it in vlc and plays fine. I installed AC3 ACM Decompressor and "lame_enc.ini" now i go to belight and still it stops encodingat the 6th minute and thats as far as it goes. Those 6 mins play fine in vlc so i assume there is no problem with the encoding.

Is this problem codec related? or am i still missing something?

[drewzor]

*//Edit

[redwudz]

AFAIK, Audacity will just accept MP3, WAV, and Ogg audio. Not AC3. But for VirtualDub, here's a guide to save out the audio as a WAV or convert directly to MP3.

http://members.dodo.net.au/~jimmalenko/ExtractAudio.htm

[avillabon]

ok little update... finally got it from ac3 to mp3 "MPEG-1 Layer 3 44100Hz 128 kb/s total (2 chnls) " should be constant bitrate....

So now i go back to virtualdubmod and select direct stream copy for video and replace the audio with the new mp3 file. Once i play the video on vlc the audio is out of sync (slightly but still noticable) while the original file is in perfect sync... any ideas?

By the way thankyou so much for being so patient!

[kschang]

Are you *sure* original AC3 is also 44.1? Usually AC3's are 48 KHz (if they're ripped from DVD's)

[drewzor]

*//Edit

[avillabon]

ok will try and post result!

[avillabon]

Well i was browsing the forum for someone who had a similar problem and someone posted the following...

"Make sure you have LAME MP3 encoder installed, as well as the AC3 ACM Decoder. Load the avi into virtualdubmod. Go streams -> Streamlist. Right-click and select Full Processing. Right-click again and select Compression. Set the MP3 compression you want to use (if you are limited to a maximum of 56kbps then you don't have LAME correctly installed). Now click Save Wav and select a folder and file name. Once this is complete, click Add and select you new wav file. Click the ac3 audio track, and then click the Disable button. Right-click the MP3 stream and select Direct Stream Copy. Finally, click OK.

Now go File->Save AVI as. Make sure the video mode is set to Direct Stream Copy. Enter a new filename and click Save.

You should now have a new version of the avi file with an mp3 audio track only. "

It worked perfectly at the first try! No need for extra software... Thanks for all the help though

Alex.