I understand that transcoding between lossy codecs is not a good idea as it can introduce artifacts. What about transcoding using the same codec? In the case I'm considering is MP3. My encodes are all using LAME 3.97b2 using -V 2 --vbr-new.

Now for example for a flash player I was to transcode some of those to say -V 5. Do I risk added additional artifacts over just the reduction in quality simply based on the different switch?

You are going to have reduced quality no matter what type of lossy to lossy encode you are doing. Why would you convert MP3 to MP3 anyway, that doesn't make much sense unless I guess your goal is to decrease file size. It really boils down to what you want to use the final product for. If its for a flash video, for me it wouldn't make much of a difference.

yes, I do understand that an encode at -V 5 is going to be lower quality than -V 2. My reason for asking is my goal is just that, to decrease file size. I have a 64meg flash MP3 player that my gf uses at times.

Sure you'll decrease the file size, but probably only enough to fit on a few more mp3s to the stick. In my opnion, I don't think that is worth the tradeoff for the reduction in quality.

Well, after the pessimistic post, it usually comes an optimistic one (sorry ajcool )

You're using a good encoder, and you're using good settings. Your original might be transparent, and the transcoded setting is useful for the purpose you desire.

I would suggest you a still lower setting. -V5 for 64MB is around one CD. Maybe less. try also with --preset 128 or --preset 112.

Past this point, any artifact you're going to hear is more prone to come from the setting than from transcoding.


Just to mention it: transcoding to the same codec, is not going to reduce the tendence of adding artifacts. It can increase them, actually.