Hi, I'm experimenting with IceCast2, using DarkIce to generate the stream. I have found some peculiarities with the vorbis bitrates. In DarkIce, I call vorbis_encode_init() with about the following values: vorbis_encode_init( &vorbisInfo, 2, 44100, 96, 96, 96); which by all reasons should generate a 96 kb/s stream, as all max_bitrate, nominal_bitrate and min_bitrate are set to 96. Strangely enough, the generated stream's bitrate (according to XMMS and WinAmp) varies between 49 and 59. If I try to set the same bitrate to a low 24, I never get a stream below about 44 kb/s. Could anyone enlighten me on these strange behaviours? It would be quite important to be able to produce a stream that still fits 33.6 kb/s modem users... Akos --- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-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.
> vorbis_encode_init( &vorbisInfo, 2, 44100, 96, 96, 96); > > which by all reasons should generate a 96 kb/s stream, as all > max_bitrate, nominal_bitrate and min_bitrate are set to 96. Strangely > enough, the generated stream's bitrate (according to XMMS and WinAmp) > varies between 49 and 59.Currently min and max are ignored by the library, since bounded bitrates aren't going in until rc3. Also, if you pick 96kbps, that picks the 96kbps mode (if there is a 96kbps mode. It might be picking the 80kbps mode. You'll have to look at the vorbisml to figure out which mode that's actually using). In any case, unlike mp3, which must be at a fixed bitrate, Vorbis won't use more bits than it needs. So often you'll get streams that are less or more than what you picked. That's the nature of VBR. It tries to keep the average at 96. What was the average of the entire encoded piece?> If I try to set the same bitrate to a low 24, I never get a stream below > about 44 kb/s.In rc2 there are no modes below 64kbps. So this sounds correct.> Could anyone enlighten me on these strange behaviours? It would be quite > important to be able to produce a stream that still fits 33.6 kb/s modem > users...If you downsample to 22.05kHz, that mode will produce much smaller files. It will also get way smaller if you use mono input rather than stereo. Vorbis currently does not do this processing for you. I believe the lowest mode that 1.0 will support at 44.1kHz is 48kbps. In any case, you really should re-ask this question on the Vorbis list, where many more people can offer you input. Once more tunings are in, and the tools do things like downsampling and downmixing for you, you'll probably not notice a big difference from what you are used to, except now and then if a song is easy to encode, it'll use less bits than you asked. For streaming applications you'll also be able to specify how much the bitrate can vary, how low and high it can go, etc. That will be quite useful. And finally, you want VBR because it sounds better. People just aren't used to VBR yet. jack. --- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-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.
buggz wrote:> Oct 20 10:30:43 buggz1 kernel: Sound: Recording overrun > Oct 20 10:31:14 buggz1 last message repeated 345 times > Oct 20 10:32:11 buggz1 last message repeated 601 times > > Anyway to correct this ?yes, your system is too slow, and can not keep up with the sound card input. are you running darkice as root? what is the system load when you run darkice or liveice? --- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-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.
Hi,
Anyone get livestreaming to work w/ massive choppiness ?
I've tried both livecast & darkice.
xmms_livecast works, as do playlist.
But when I do live soundcard streaming, I see this:
Oct 20 10:30:43 buggz1 kernel: Sound: Recording overrun
Oct 20 10:31:14 buggz1 last message repeated 345 times
Oct 20 10:32:11 buggz1 last message repeated 601 times
Anyway to correct this ?
--
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Jack Moffitt wrote:> > vorbis_encode_init( &vorbisInfo, 2, 44100, 96, 96, 96); > > Currently min and max are ignored by the library, since bounded bitrates > aren't going in until rc3.Also, aNa|0Gue pointed it out that the values need to be in b/s, so 96000 instead of 96.> In rc2 there are no modes below 64kbps. So this sounds correct.Actually I found that the minimum for 44.1kHz is 32 kb/s. Thanks for the help. I think I'm gonna put some downsampling code into DarkIce soon.. Akos --- >8 ---- List archives: http://www.xiph.org/archives/ icecast project homepage: http://www.icecast.org/ To unsubscribe from this list, send a message to 'icecast-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.