Is ac3-stereo-->ogg recommended?

[Sujao]

Hi all,

what do you think about the conversion of ac3-stereo streams to ogg? Would there be lots of quality loss? I am dumping a ac3-stream converting it to PCM and the PCM to ogg vorbis.

I encoded to ogg vorbis with quality setting 3 and a resulting average bitrate of 79.9 kb/s. A ac3-stereo sound stream of 168MB became 53MB and I couldnt hear any difference although I must say that the movie i ripped from is pretty old and the original sound quality was rather poor.

So what are you thoughts about ac3-stereo -> ogg vorbis conversion? Is it worth it or does one get serious quality losses?

[obieobieobie]

You will of course get a quality loss when encoding to a lossy format. That being said, if you can't hear a difference or if you think the space savings are worth it even though you can hear a difference, I say go for it.

Personally, I think Vorbis is great for low bitrates (it's one of the design goals for Vorbis) and if I'm going to save space I'll go for vorbis in matroska every time. :)

[Sujao]

Hi obieobieobie,

of course I will loose quality with a lossy codec but dont know the structure of ac3-stereo. Maybe is strongly fragmented so that REencoding to ogg would be EXTRA lossy. As you surely know you shouldnt rencode MP3s to OGG by all means so I wandered if its the same with AC3.

[Tommy B.]

Why that? You may also reencode a MP3 to Vorbis. As long as you can't
hear the difference, it should be okay.

If you take a 256kbit MP3 and encode it to 128kbit Vorbis, it might
sound just the same.