Compressing with Lame-3

[tifferx]

I have been trying to convert several DivX files with VBR mp3 audio to having CBR mp3 audio.

In a number of the guides, I have seen compression by Lame-3 as an option.

Unfortunately this is not offered in my version of VDub nor VDubMod.

How can I install Lame-3 into my programs?

Thanks in advance.

[vlada]

Install LAME ACM codec. You can find it at www.rarewares.org.
Btw. do you know that transcoding MP3 VBR to MP3 CBR will hurt the audio quality quite a lot?

[tifferx]

Btw. do you know that transcoding MP3 VBR to MP3 CBR will hurt the audio quality quite a lot?

The method I was planning to use:

Open AVI file (that has VBR mp3 audio).
Save WAV (Audio > Full stream processing).
Audio > Full stream processing > WAV audio (selecting the WAV file just created).
Audio > Compresion > Lame-3 (CBR mp3).
File > Save as AVI (using Video > Direct stream copy).

Do you recommend a better method?

Re: Installing Lame-3:
I seem to be having a little difficulty. I can get it to show in Audacity (but without any compression options).
I'll hold off with my efforts for now - until I have your response concerning the above.

Thanks.

[vlada]

If you want to transcode MP3 VBR to MP3 CBR, you will loose the quality no matter what you're doing. So there is no good way to do it.

You can try this:
1) Download "LAME 3.97 Release ACM: VC6 compile. Includes inf file." from RareWares. Unpack it, right cilck the .inf file and choose "install". After you install the LAME ACM codec, it will be available in VirtualDub.
2) Open your movie in VD/VDM, choose "Direct Stream Copy" for video and "Full Processing" for audio. Select LAME as audio codec and set target CBR bitrate. Ther's no need to save a WAV file.
3) Save your AVI.

This method might cause synchronization problems. If this happens, then you need to do it another way. Use AVI-Mux GUI to demux audio track to MP3. Transcode your MP3 to CBR in whatever program you want to (foobar2000, LameDrop, Omni Encoder, BeLight, WinLAME etc.) Btw. LAME encoder settings in Audacity can be found within global preferences of the program.

Anyway I still don't understand why you want to transcode MP3 VBR to MP3 CBR. Do you have a standalone player which doesn't support MP3 VBR?

Edit: I just recalled there is a tool, which can convert VBR to CBR losslessly. You can find some information about the program at HydrogenAudio (http://www.hydrogenaudio.org/forums/index.php?showtopic=32379). Of course using this tool will increase the size of your MP3. If you have an MP3 VBR 32-224 kbps, average 100 kbps, the resulting MP3 will be 224 kbps, so more then twice as big. But there will be no quality loss!

[tifferx]

Many thanks Vlada.

My project is compiling DivX-discs of sports footage from a variety of sources. Unforunately this footage has already been compressed in various video and audio formats.
For the purposes of better editing using VD / VDM, I wanted to convert any files in VBR audio into CBR audio.
Also for consistency throughout the disc.

I do want my discs to play on a standalone player - but I haven't yet tested to see if it supports VBR audio.

As it is sports footage, the sound quality isn't hugely important - as long as it's in sync and doesn't sound unpleasant.
Interviews are different though.

Thanks very much for your replies - you've been very helpful.
And I've now found the options in Audacity.

Regards.

[Schnoodledorfer]

One problem you will probably run into is that the headers of the VBR MP3 files you get when you demux may have incorrect information in them. The bitrates, play times, etc. reported by various utilities will be off, but the actual audio in the file will be read and played correctly. In other words, it will look like it didn't demux correctly, but (other than the headers) it probably did.

I use an MP3 editor called MP3DirectCut (http://mpesch3.de1.cc/) just to open, then save the MP3 files, without actually editing them. It writes the headers out correctly when it saves the file. At least you know what you are starting out with that way. I assume many other MP3 editors would fix the headers too.

If you don't do that, the transcoding should probably work OK, and the new files should be written out with correct headers. You just have to ignore the information reported about your VBR MP3 file in the mean time.