<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial,helvetica,sans-serif;font-size:10pt"><div>Hello,<br><br>I've also implemented it the way Silvia said. However, is there a better (or faster) way of finding the last Ogg page in a stream than scanning the last 64 K (which is the maximum possible page size) of the stream for a page header capture pattern?<br><br>Thanks,<br>Mathias K.<br><br></div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">Von:</span></b> Silvia Pfeiffer <silvia@silvia-pfeiffer.de><br><b><span style="font-weight: bold;">An:</span></b> Lucas Clemente Vella <lvella@gmail.com><br><b><span style="font-weight: bold;">CC:</span></b> vorbis-dev@xiph.org; 揭磊平
<jxren0626@163.com><br><b><span style="font-weight: bold;">Gesendet:</span></b> Dienstag, den 26. Januar 2010, 7:47:29 Uhr<br><b><span style="font-weight: bold;">Betreff:</span></b> Re: [Vorbis-dev] How to get the actual bitrate?<br></font><br>On Tue, Jan 26, 2010 at 2:17 PM, Lucas Clemente Vella <<a ymailto="mailto:lvella@gmail.com" href="mailto:lvella@gmail.com">lvella@gmail.com</a>> wrote:<br>> 揭磊平 escreveu:<br>>> Dear all:<br>>> I'm a developer in china, and i really want to know how to calculate a ogg audio file's bitrate and then i can get the duration by file size.<br>>> thanks very much for your answer.<br>><br>> See, most of ogg vorbis files have variable bitrate, so the way to<br>> calculate its mean bitrate -- the only significant bitrate when speaking<br>> of the whole stream -- is size/duration, what imply you must know the<br>> duration beforehand.<br>><br>> I'm
afraid you can't know the duration of the stream by just looking at<br>> the file size, since even libvorbis must be able to seek through the<br>> stream to be able to determine it's duration.<br><br>You can seek to the last page, decode the granulepos and calculate the<br>duration from that.<br><br>Cheers,<br>Silvia.<br>_______________________________________________<br>Vorbis-dev mailing list<br><a ymailto="mailto:Vorbis-dev@xiph.org" href="mailto:Vorbis-dev@xiph.org">Vorbis-dev@xiph.org</a><br><a href="http://lists.xiph.org/mailman/listinfo/vorbis-dev" target="_blank">http://lists.xiph.org/mailman/listinfo/vorbis-dev</a><br></div></div>
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