[mythtv-commits] Ticket #8365: [BUG FIX] White noise on PulseAudio frontend output
MythTV
mythtv at cvs.mythtv.org
Sun Apr 18 18:05:34 UTC 2010
#8365: [BUG FIX] White noise on PulseAudio frontend output
-------------------------------------------------+--------------------------
Reporter: Carlos Azevedo <geral@…> | Owner: janne
Type: defect | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - Video Playback | Version: Trunk Head
Severity: medium | Mlocked: 0
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Problem:
When watching LiveTV audio plays for a bit then turns to white noise (like
a out-of-tune TV set).
Cause:
Line 558 of file libs/libmyth/audiooutputpulse.cpp reads as :
{{{
fragment_size = (float)sample_rate * 0.020f * // 20msec
(float)(audio_bits / 8 * audio_channels);
}}}
For whatever reason GCC compiles this and with values sample_rate=48000,
audio_bits=16 and audio_channels=2 the computed result is 3839 (should be
3840).
The result is not divisible by (audio_bits / 8 * audio_channels) so on
buffer resets the audio stream will get 'out of phase', playing white
noise instead.
Fix:
Change line 558 to :
{{{
fragment_size = (sample_rate * 20 * // 20
msec x 1000
(audio_bits / 8) * audio_channels) / 1000; // base
on msec ( div 1000 )
}}}
Since this is a two-liner and I'm still tracking other issues I didn't
write a proper patch. If that's a problem let me know.
--
Ticket URL: <http://svn.mythtv.org/trac/ticket/8365>
MythTV <http://www.mythtv.org/>
MythTV
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