[vorbis-dev] getting playback length from ogg vorbis file

[Lourens Veen]

On Fri 11 July 2003 12:31, Lourens Veen wrote:
> On Fri 11 July 2003 12:06, Jack Angel wrote:
> > On Thu, 10 Jul 2003 17:39:36 -0600
> >
> > Jack Moffitt <jack at xiph.org> wrote:
> > > > I need to extract playback length from ogg vorbis file,
> > > > with 1/100th second precision. The ogginfo program tells
> > > > the playback length to 1 second precision. Why not to
> > > > change ogginfo? I suppose many automatic tools need
> > > > precision higher than 1 second.
> > >
> > > I think changing ogginfo is reaosnable.
> >
> > I think so too, because ogg123 reports play time / current time
> > to 1/100th second precision. Ogginfo should too. I need it
> > because I want to do queries to cddb based on several ogg
> > vorbis tracks, and cddb has got resolution of 75 cd frames per
> > second - for it to work, i've got know ogg length to pretty
> > high res. Will somebody do this, or maybe I've got to do it
> > myself (if I figure the sources ;)?.
>
> How is this patch (against ogginfo2.c in vorbis-tools-1.0):

Hold on, that seems to give incorrect results. There is something 
fishy there with the floor() construction. This seems to work 
better:

--- ogginfo2.c.old      Fri Jul 11 12:16:04 2003
+++ ogginfo2.c  Fri Jul 11 12:36:41 2003
@@ -373,19 +373,20 @@
 static void vorbis_end(stream_processor *stream)
 {
     misc_vorbis_info *inf = stream->data;
-    long minutes, seconds;
+    long minutes, seconds, seconds100;
     double bitrate, time;

     time = (double)inf->lastgranulepos / inf->vi.rate;
     minutes = (long)time / 60;
     seconds = (long)time - minutes*60;
+    seconds100 = (long)((time - minutes*60 - seconds)*100.0);
     bitrate = inf->bytes*8 / time / 1000.0;

     info(_("Vorbis stream %d:\n"
            "\tTotal data length: %ld bytes\n"
-           "\tPlayback length: %ldm:%02lds\n"
+           "\tPlayback length: %ldm:%02lds.%02ld\n"
            "\tAverage bitrate: %f kbps\n"),
-            stream->num,inf->bytes, minutes, seconds, bitrate);
+            stream->num,inf->bytes, minutes, seconds, seconds100, 
bitrate);

     vorbis_comment_clear(&inf->vc);
     vorbis_info_clear(&inf->vi);

<p>Also, I understand why this works :-). But I still don't see why
(long)((time - floor(time) * 100.0) doesn't work...

Lourens

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