audio codecs..... why and how

[dvnoob]

Ok, I see codecs like lagarith, mainconcept dv codec, and huffyuv..... I install them and now what? How do you use them? I am using dvapp to "capture" dv to avi, then i will prolly use tmpgenc plus or mainconcept encoder to convert the avi to vob for authoring. I will prolly be using tmpgnc dvd author 1.6 to create the dvds. where in these steps do i use these codecs? and how do i do that? THANKS!

[guns1inger]

DV transfer through a program like DV App or WinDV is essentially a data transfer exercise. You are transfering data from the camera to your PC, and storing it inside an avi container. To read this, or to alter it and keep it DV, you need a DV codec. In your case, you will then encode to mpeg2 using tmpgenc or mainconcept, and burn to DVD. You won't need to install or use any other codecs.

The other codecs you see mentioned all have different uses and strengths and weaknesses. Codecs like Divx and Xvid are relatively efficient at compressing video - moreso than mepg2 or DV - and so are good for making smaller files for transfering across networks. Their compression does come at a cost however, and that cost is quality. You cannot expand a Divx compressed file back to it's original form, as a lot of information has been thrown away inthe compression process.

The idea, if maintaining quality is of paramount concern, is uncompressed video. However this requires enormous amounts of disk space and computing power to process. The advantage is that with no compression, no data is ever lost. The compromise is lossless compression codec, such as Huffyuv or Lagarith. These still require relatively high amounts of space, but far less than uncompressed video, yet they do not damage the image because they can be expanded back to their original state.

There are hundreds of codecs around, many derivatives of the same standards. Each has a place, although for many that place is very small.

As a general rule, if you don't need a codec, don't worry about it, and don't install it. If you find something you can't open, use G-Spot or Avicodec to see what is required, and install just that codec.

[kschang]

And NONE of those are audio codecs.

[guns1inger]

I didn't want to confuse the matter by pointing that out.

[dvnoob]

so, then in other words, if i am not compressing anywhere along the way (and im not), i don;t have to worry about them at all. By all the reading i have been doing, the only other thing i think i would like to do is convert the audio, on the dv tape, from whatever it is currently, lcpm or 2 channel something? to 5.1 or ac3 5.1 ?? how do i do that? i used ffmpeggui as a test but it didn't make it 5.1, not sure if it does, if not any suggestions? You guys rock on this site BTW, its awesome, full of knowledge, and I am greatful that i came across it! Thanks.

[guns1inger]

You are doing at least one compression - DV to mpeg-2. Otherwise, you appear to be doing very little to the video.

You only have stereo from your camera, so there usually isn't much to be gained trying to mix down a 5.1. 2.0 is more than adequate in most cases. If you do want to try a 5.1, you will need suitable software (Surcode, Vegas+DVD) and some way to create the extra channels. I wrote this guide a while back for Sound Forge/Vegas. It might be of use.

https://forum.videohelp.com/viewtopic.php?t=292142&start=0

[greymalkin]

You may want to (especially if this is your first time) go ahead and get familiar with the process that suits you best for encoding to mpeg2 and AC3 2.0...later on if you record something and have additional audio feeds that warrant a full surround mix then you can play with that.

really though if you've just got stereo and someone wants it to be in surround they can just use the built in settings on their surround sound receiver.

[dvnoob]

thats true! thanks guys.