On Sun, 29 Aug 2004 17:53:29 -0700, Ralph Giles wrote:> On Mon, Aug 30, 2004 at 03:03:28AM +0100, Andy Baxter wrote: > >> Is there any way to bring the bitrate in ices2 down below 32 kbps? > > Generally the trick for this is to downsample the audio before encoding. > You can ask ices to do this with a resample stanza in the config file: > > <resample> > <in-rate>44100</in-rate> > <out-rate>22050</out-rate> > </resample>Thanks, that does it.> >> Specifically, I have a machine with 2 versions of oggenc on it, one >> from debian woody, and one compiled from source. The woody version will >> encode mono wavs down to 16kbps, but the (later) hand compiled version >> will only go down to 32 kbps. The quality of the 16kbps files isn't that >> great, but it's still ok to listen to - no obvious distortion or spurious >> noises, just a loss of clarity. > > You don't tell us what compression options you tried, but hopefully the > resampling issue is the one you're missing. >The ones I've tried are: channels sample rate nominal bitrate 2 44100 65536 good stereo sound 2 44100 131072 probably better but I can't hear the difference. 1 44100 32768 streams at 35-40 kbps, good sound 1 44100 16384 encoder won't start. 1 22050 16384 streams at about 25 kbps 1 14700 16384 streams at about 21-23 kbps. starting to sound bad. 1 22050 16384 with managed bitrate, max=18000. works, but sounds weird and metallic. 1 11025 16384 streams at 19-20 kbps. sounds flat and dull. I reckon I should be able to find something that will do alright from these, so cheers. andy.
On Mon, Aug 30, 2004 at 03:03:28AM +0100, Andy Baxter wrote:> Is there any way to bring the bitrate in ices2 down below 32 kbps?Generally the trick for this is to downsample the audio before encoding. You can ask ices to do this with a resample stanza in the config file: <resample> <in-rate>44100</in-rate> <out-rate>22050</out-rate> </resample>> Specifically, I have a machine with 2 versions of oggenc on it, one > from debian woody, and one compiled from source. The woody version will > encode mono wavs down to 16kbps, but the (later) hand compiled version > will only go down to 32 kbps. The quality of the 16kbps files isn't that > great, but it's still ok to listen to - no obvious distortion or spurious > noises, just a loss of clarity.You don't tell us what compression options you tried, but hopefully the resampling issue is the one you're missing. -r
Is there any way to bring the bitrate in ices2 down below 32 kbps? I'm setting up a demo for someone of how to use linux to do net radio broadcasting. The setup I'm thinking of is to use ardour plus jack to mix two (maybe more) input sources (live audio and recorded tracks/programmes), then send the mixed audio to ices2 for streaming to icecast2, using the jackified version of ices2. This is all working OK. The problem is, I'm trying to set it up to use peercast peer to peer streaming, so as to cut down the amount of bandwidth that the server needs. This means every listener needs to have enough bandwidth to relay at least one stream out as well as in. What I was thinking of is to broadcast 2 ogg streams ; one at 64kbps stereo for broadband listeners, and another at 16kbps mono for dialup listeners, and maybe get a few people with good connections to have a permanent peercast relay for both these streams. But as far as I can see, ices2 won't encode at below 32 kbps, which won't work with peercast on 56k dialup links. I remember from the vorbis documentation that it's supposed to work down to 16 kbps per channel, and the old vorbis encoder for linux used to do this, so has something changed in the specification? Specifically, I have a machine with 2 versions of oggenc on it, one from debian woody, and one compiled from source. The woody version will encode mono wavs down to 16kbps, but the (later) hand compiled version will only go down to 32 kbps. The quality of the 16kbps files isn't that great, but it's still ok to listen to - no obvious distortion or spurious noises, just a loss of clarity. If there's any way to get ices2 to encode to 16kbps mono, could someone let me know how? -- Please don't send me html mail or un-notified attachments. These will be automatically filed under 'probable spam' unless I'm expecting an email which hasn't come. If you do need to send an attachment or html mail, put [attachment] or [html] in the subject line. Thanks, andy.
On Mon, 30 Aug 2004 03:03:28 +0100, Andy Baxter wrote:> Is there any way to bring the bitrate in ices2 down below 32 kbps? >Thanks for the replies to this - I'm getting there. One more question is whether the sample rates that are typically used (44100, 48000, 22050) are just conventions, or if there's any reason to stick to these. E.g. are there players which will only handle oggs at these rates?