I am a newbie here so this may be a well worn topic... I am working on a cd compilation that would combine speech such as lectures and music. I have many speeches that are 60 to 90 minutes in length and would like to compress them as much as possible. I have one in mp3 format with the following specs: Size: 13603893 bytes Header found at: 0 bytes Length: 3733 seconds MPEG 2.5 layer 3 29kbit (VBR), 142925 frames 11025Hz Mono CRCs: No This 13mb file has very acceptable voice quality and plays for over 100 minutes I think. The vbr bounces between 8 and rarely 32 kbit. I believe that even 8khz Mono would be satisfactory for such voice but my understanding is that ogg doesn't go that low. Now that speex has joined xiph, will ogg be able to handle the low end for speech? Being able to get 80-100 hours of speech onto a cd would be a boon to economically sharing. Anything like that possible in the near future? <p>__________________________________________________ Do you Yahoo!? Yahoo! Web Hosting - Let the expert host your site http://webhosting.yahoo.com --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
> >I believe that even 8khz Mono would be satisfactory >for such voice but my understanding is that ogg >doesn't go that low. Now that speex has joined xiph, >will ogg be able to handle the low end for speech? >Ogg Vorbis can go that low, or even lower, without any real difficulty. If you want to go REALLY low (significantly lower than the example mp3 you gave), vorbis won't do so well, speex will be much better. Either way, speex is worth trying, but vorbis may well be what you want. Michael <p>--- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
f u wrote:> I believe that even 8khz Mono would be satisfactory > for such voice but my understanding is that ogg > doesn't go that low. Now that speex has joined xiph, > will ogg be able to handle the low end for speech?8kHz is well possible with Vorbis. Try qualities -1 to 1 with 8kHz/mono and 11kHz/mono input, to find a version that you like best. You'll likely find Vorbis to give acceptable results down to 12-16 kbps. 8kHz/mono @ -q -1 is *really* low-end, however, I'm sure the result will be better than your MP3 in any case. Make sure that you use the 1.0 release of Ogg Vorbis for your experiments. Speex is a pure voice codec, so you're unlikely to get very great results if your voice samples also contain music (although I must admit that I haven't done any tests, yet, since I have zero speech samples to play with). If there are voice-only samples, you'll get much better results with Speex at even lower bitrates than with Vorbis. <p>Moritz --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.