ac3 mp3 and ogg (versus)

[hubereevez]

Hi,
it's a newbie question so forgive me..........
I red (doom9 and www.r3mix.net) that for higher bitrate mp3 gives a better quality than ogg. But when I have a long movie I use ogg to reduce the audio part. My question is : is that a mistake to encode with a high bitrate (--r3mix or lower in lame) from ac3 to mp3 for shorter movie (1h30)? ac3 has a max bitrate, so till which value can I encode in mp3 without loosing space?
thanks
hubhub

[LigH]

Please don't be angry too much, but ... such kind of question is debated much too often without any useful results.

The higher the bitrate is, the closer a compressed audio may come to the original. Most people can't tell the original from the compressed up from around 160-192 kbps with a good MP3 encoder (the Dolby Digital compression algorithm is almost identical), and up from quality 3 with Ogg Vorbis RC3. Comparing the quality above these ranges is academical: You may be able to measure different grades of differences, but you may hardly be able to prove this by just listening. And finally: When transcoding an already psychoacoustically compressed audio, the resulting quality can't become better.

All I can recommend is that you just do a listening test with a rather short audio (e.g. a short song from a CD); you can use BeSweet to encode this WAV file to MP3, AC3 and Ogg. Listen from the higher to the lower bitrates (or quality for Ogg) and decide from which you can just notice differences, and from which the artifacts start to disturb. Then you'll see that discussing the quality above a certain range is really useless for the purpose of adding a movie soundtrack - it may only be interesting for archiving the best possible quality (beyond your personal listening capabilities) with a fair file size.