2011/5/2 Martin Konečný <[email protected]>: > Hey Romain, Thanks for clarifying that up, so maybe we will have the ability > to jump to different positions in tracks for Liquidsoap 2.0 :). > I'm going to do some tests this week to see which is faster: Cutting off the > first 50 minutes of an mp3/ogg file, or having liquidsoap "process" all data > up to the 50 minute mark. I'll post my results here.
Well, don't spend too much time on that, I might have something to announce pretty soon concerning this issue :-) Romain > Thanks! > Martin > 2011/4/29 Romain Beauxis <[email protected]> >> >> Hi! >> >> 2011/4/29 Martin Konečný <[email protected]>: >> > Hi Samuel, >> > Regarding Ticket # LS-469: http://dev.sourcefabric.org/browse/LS-469 >> > Could you detail why Liquidsoap would have a very high CPU usage if I >> > were >> > to set a cue point more than a few seconds from the beginning of a >> > track? >> > One use-case we were hoping to address with this feature was restarting >> > playback from a specific point in a track after a power failure. One of >> > our >> > users has a radio station in an area where the power goes out a few >> > times a >> > day, and some of their tracks are pre-recorded shows up to an hour long. >> > We wanted to make it so that if the power goes out with 10 min left of a >> > one >> > hour show, they simply need to restart their system and we use >> > liquidsoap to >> > jump to the 50 min mark. >> >> That's a very interesting case! >> >> > I am curious why I can jump to any point in a track with media players >> > such >> > as Banshee and Rhythmbox instantaneously, but Liquidsoap cannot. >> >> The problem is that Liquidsoap has always been designed as a _stream_ >> processing "engine". It works chunk by chunk to generate a stream. >> This internal specification is very appropriate for many reasons but >> also entails some limitations (one of which being the skip vs. >> crossfade problem you mentioned and on which I still have to reply..) >> >> When decoding a file, liquidsoap processes data frame by frame until >> it ends. It has some limited view concerning the future, namely an >> estimation of the remaining time for files and, in the case of >> crossfade in conservative mode, a small buffer of data (which should >> be the solution for your skip and cross issue: pass conservative=true >> to the crossfade operator). >> >> So, for now, we do not have any notion of skiping data in file >> decoders. The cue point operator is implemented for now by decoding >> all the data to skip at once at the beginning of the track and that is >> what may cause high CPU usage. (the problem does not occur at the end >> of the track). >> >> Ideally, we should have a notion of skipping for file decoders. >> However, I am not so sure about how this could be implemented. I >> believe that it could be a source's property, that is only available >> when possible (i.e. the source is a playlist, single but not >> input.http etc..) >> However, this probably requires a fairly large amount of work and >> would also require the implementation of a skipping method for each >> format (and don't get me started on the mess concerning mp3 data..) >> (or the ogg muxing format also..) :-) >> >> All in all, I would say the following: >> * For now Sam's operator is nice for cue points that are close to the >> beginning of the file, which is usually the case for instance with >> crossfading. >> * For you specific case, a cut_file protocol would probably be enough >> (files are mp3 or ogg/vorbis?). >> >> In the long term, I would like to have a skiping data support in >> liquidsoap. However, I believe that is too much of a core change for >> now, because we are still working on the 1.0 stable release... >> >> >> Romain >> >> > Regards, >> > Martin >> > P.S. Thanks for the quick implementation of this feature. Even in its >> > current state we will have uses for it :) >> > >> > -- >> > Martin Konecny >> > Software Developer, Sourcefabric >> > [email protected] >> > >> > >> > ------------------------------------------------------------------------------ >> > WhatsUp Gold - Download Free Network Management Software >> > The most intuitive, comprehensive, and cost-effective network >> > management toolset available today. Delivers lowest initial >> > acquisition cost and overall TCO of any competing solution. >> > http://p.sf.net/sfu/whatsupgold-sd >> > _______________________________________________ >> > Savonet-users mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/savonet-users >> > >> > > > > > -- > Martin Konecny > Software Developer, Sourcefabric > [email protected] > > 720 Bathurst St. Suite 203 > M5S 2R4, Toronto, ON, Canada > +1 (416) 892-8420 (Cell) > Skype: martin.konecny15 > > http://www.sourcefabric.org > http://www.twitter.com/Sourcefabric > ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Savonet-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/savonet-users
