[RDD] Ignoring End Markers?

Frederick Gleason fredg at paravelsystems.com
Mon Jan 12 17:33:25 EST 2015

On Jan 12, 2015, at 12:57 07, James L. Stewart <jstewart at paceaudio.com> wrote:

> The problem is when the setup is having the sound card hardware itself do the mixing of the two streams.  In this case you have to be careful that both streams are the same audio format (bit rate, sample rate, codec type, stereo/mono, etc.), especially the sample rate

Rivendell will happily mix together streams with different formats, bit rates and channel counts.  However, with different *sample* rates, things can get slightly more complicated.  Under normal circumstances, all of the material in a Rivendell library should be recorded using the same sample rate — the one configured in RDAdmin->SystemSettings.  However, it is possible (especially if the site in question was upgraded from an earlier 1.x setup) that it contains cuts with mixed sample rates.  If that happens, the symptoms will differ depending on the specific audio hardware framework in use:

1) ALSA — will often show up as noise or distortion a few seconds after starting playback when playing a cut with the ‘wrong’ sample rate —i.e. a rate different from that configured in RDAdmin->SystemSettings.

2) JACK — will show up as a play out who's audio is pitch shifted

3) ASI - ASI5xxx — will show up as a play out who's audio is pitch shifted

4) ASI - ASI6xxx — will play correctly.  (This is because ASI6xxx cards are natively capable of playing multiple streams with differing sample rates simultaneously).


| Frederick F. Gleason, Jr. |              Chief Developer             |
|                           |              Paravel Systems             |
|          A room without books is like a body without a soul.         |
|                                         -- Cicero                    |

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