Re: Musepack support
Christian HJ Wiesner <[email protected]> Wed, 06 Feb 2008 18:25:38 +0100
| Newsgroups | gmane.comp.multimedia.matroska.devel,gmane.comp.audio.mpc.devel |
|---|---|
| Message-ID | <[email protected]> |
--===============0326847745== Content-Type: text/html; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-15" http-equiv="Content-Type"> </head> <body bgcolor="#ffffff" text="#000000"> <br> <br> Dear Nicolas,<br> <br> sorry for not replying earlier, it was Liisachan pointing me to the fact that nobody from the team has replied to your request.<br> I dont know what happened, it is possible that your email did not catch our devs attention, for whatever reason. Once again, apologies for that.<br> <br> For muxing of Musepack into matroska, i recommend to have a close look at the <a href="http://www.matroska.org/technical/specs/codecid/index.html">specs</a> of how most other audio streams are being muxed into matroska, as we should definitely try to maintain this line of how the other audio codecs were being handled. Probably the most up-to-date version of the specs is available as a PDF from <a href="http://haali.cs.msu.ru/mkv/codecs.pdf">Haali's site</a>, but i guess the differences are mainly of interest for video codecs, not audio, so what you find on matroska.org should be OK.<br> <br> IIRC then musepack once was derived from MP2, so maybe it is possible to use a similar way to put the MPC audioblocks into MKV/MKA as was used for MP2 and MP3 ? This is of course a very simple way of doing things, as the MP 2/3 streams in matroska are directly taken out of the MPEG container, thats it.<br> <br> Should this not be feasible for MPC SV8, definitely the most advanced way to mux audio into matroska have been used for Vorbis, DTS and Wavpack. For Vorbis, this is described on the specs page as follows :<br> <br> ---------------------------------------------------------------------------------------------------------------------------------------<br> The private data contains the first three Vorbis packet in order. The lengths of the packets precedes them. The actual layout is:<br> Byte 1: number of distinct packets '<code>#p</code>' minus one inside the CodecPrivate block. This should be '2' for current Vorbis headers.<br> Bytes 2..n: lengths of the first '<code>#p</code>' packets, coded in <a href="http://www.matroska.org/technical/specs/index.html#lacing">Xiph-style lacing</a>. The length of the last packet is the length of the CodecPrivate block minus the lengths coded in these bytes minus one.<br> Bytes n+1..: The <a href="http://www.xiph.org/ogg/vorbis/doc/vorbis-spec-ref.html"> Vorbis identification header</a>, followed by the <a href="http://www.xiph.org/ogg/vorbis/doc/v-comment.html"> Vorbis comment header</a> followed by the <a href="http://www.xiph.org/ogg/vorbis/doc/vorbis-spec-ref.html"> codec setup header</a>.<br> ----------------------------------------------------------------------------------------------------------------------------------------<br> <br> We are completely open to your suggestions in this respect, you do know Musepack SV8 better than we do, and can compare it to other existing audio compression formats better than we could.<br> <br> Once you decided on a preferred way of muxing the musepack packets into matroska, we should fix a clear, unique identifier for it, like :<br> <br> A_Musepack_8<br> <br> or<br> <br> A_MPC_SV8<br> <br> or the like.<br> <br> Once this is done, the hard job will come :<br> <br> Now we need to convince Mosu and Alex Noe, the devs of the most important muxing tools for MKV, to implement musepack support into their muxing tools. To do so most easily, they need to be provided with the following :<br> <br> - a very clear spec of the format itself, and the way the audio packets should be muxed into matroska, including headers etc.<br> - if possible some example code for a demuxer and muxer (for mkvextract), preferably in C or C++<br> <br> If we will have this step accomplished, all the rest (getting playback support, updating the specs, etc.) will be quite easy ;-) ....<br> <br> Best Regards<br> <br> Christian<br> <br> Nicolas Botti schrieb: <blockquote cite="mid:[email protected]" type="cite">Hello, <br> <br> Musepack sv8 is in beta stage. One off the goals was to be able to mux it in another container. <br> So I would like to define how to mux it in Matroska. What needs to be done ? <br> Thanks for your help. <br> <br> Nicolas <br> </blockquote> </body> </html> --===============0326847745== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Matroska-devel mailing list [email protected] http://lists.matroska.org/cgi-bin/mailman/listinfo/matroska-devel Read Matroska-Devel on GMane: http://dir.gmane.org/gmane.comp.multimedia.matroska.devel --===============0326847745==--