[mythtv-users] AC3 audio problems

Eric Sharkey eric at lisaneric.org
Sun Jan 11 23:16:35 UTC 2009


On Sun, Jan 11, 2009 at 4:23 PM, Matthew <m.mythtv at grojguys.com> wrote:
> Erik, glad that worked for you.

I still haven't got it 100% working.  On some select HD recordings I'm
getting audio drop outs:

2009-01-11 18:04:37.463 AFD: Opened codec 0x833aa00, id(MPEG2VIDEO) type(Video)
2009-01-11 18:04:37.463 AFD: codec AC3 has 2 channels
No accelerated IMDCT transform found
2009-01-11 18:04:37.463 AFD: Opened codec 0x8310d90, id(AC3) type(Audio)
2009-01-11 18:04:39.150 AFD: Opened codec 0x833a0e0, id(MPEG2VIDEO) type(Video)
2009-01-11 18:04:39.150 AFD: codec AC3 has 6 channels
No accelerated IMDCT transform found
2009-01-11 18:04:39.150 AFD: Opened codec 0x8368f70, id(AC3) type(Audio)
2009-01-11 18:04:40.859 AFD: Opened codec 0x833a0e0, id(MPEG2VIDEO) type(Video)
2009-01-11 18:04:40.859 AFD: codec AC3 has 6 channels
No accelerated IMDCT transform found
2009-01-11 18:04:40.860 AFD: Opened codec 0x8368f70, id(AC3) type(Audio)
2009-01-11 18:04:40.989 TV: Attempting to change from None to
WatchingPreRecorded
2009-01-11 18:04:41.166 AFD: Opened codec 0x833b080, id(MPEG2VIDEO) type(Video)
2009-01-11 18:04:41.166 AFD: codec AC3 has 6 channels
No accelerated IMDCT transform found
2009-01-11 18:04:41.167 AFD: Opened codec 0x84ad450, id(AC3) type(Audio)
2009-01-11 18:04:41.168 Opening audio device 'default'. ch 2(2) sr 48000
2009-01-11 18:04:41.168 Opening ALSA audio device 'iec958:{ AES0 0x02 }'.
2009-01-11 18:04:41.178 Mixer unable to find control Master 1
2009-01-11 18:04:41.178 mixer unable to find control Master 1
2009-01-11 18:04:41.179 Opening audio device 'default'. ch 2(2) sr 48000
2009-01-11 18:04:41.179 Opening ALSA audio device 'iec958:{ AES0 0x02 }'.
2009-01-11 18:04:41.184 Mixer unable to find control Master 1
2009-01-11 18:04:41.184 mixer unable to find control Master 1
2009-01-11 18:04:41.190 VideoOutputXv: XVideo Adaptor Name: 'NV17 Video Texture'
2009-01-11 18:04:41.232 OSD Theme Dimensions W: 640 H: 480
2009-01-11 18:04:41.393 TV: Changing from None to WatchingPreRecorded
2009-01-11 18:04:41.394 Realtime priority would require SUID as root.
2009-01-11 18:04:41.496 Video sync method can't support double
framerate (refresh rate too low for bob deint)
2009-01-11 18:04:41.497 FilterManager: failed to load filter 'none',
no such filter exists
2009-01-11 18:04:41.497 Couldn't load deinterlace filter none
2009-01-11 18:04:41.497 Video timing method: USleep with busy wait
2009-01-11 18:04:41.667 AFD: Opened codec 0x9416e20, id(MPEG2VIDEO) type(Video)
2009-01-11 18:04:41.667 AFD: codec AC3 has 6 channels
No accelerated IMDCT transform found
2009-01-11 18:04:41.667 AFD: Opened codec 0x9415e10, id(AC3) type(Audio)
2009-01-11 18:04:42.572 WriteAudio: buffer underrun
2009-01-11 18:04:43.003 WriteAudio: buffer underrun
2009-01-11 18:04:43.257 WriteAudio: buffer underrun


Then there are a lot more of these WriteAudio buffer underrun
messages.  The hardware is capable of playing back the video smoothly.
 mplayer has no trouble with it.  I've run top remotely while the
video is playing through MythTV and the machine seems to be 60%-80%
idle on each core (Core 2 Duo).  I've tried multiple different CPU
playback profiles and it doesn't seem to make any difference.  I've
also toggled "aggressive sound card buffering" and other settings but
I haven't found any combination of settings to make it any better.

Eric


More information about the mythtv-users mailing list