[mythtv] [mythtv-commits] Ticket #1104: multi channel audio support

Sat Dec 22 16:41:23 UTC 2007

Paul Catchpole wrote:
> Mark Spieth wrote:
>   
>>>  Sorry, again I have to correct myself. I now know what you mean with
>>> "rumble". With FILTERED_LFE defined I do have rumble (only with watching
>>> TV, mythvideo and mythmusic are fine). The problem I noticed before
>>> (without FILTERED_LFE defined) is more like an echo in LFE or like LFE is
>>> not playing the correct data. I don't know how to describe this further.
>>> This is just happening while watching TV. mythvideo and mythmusic are
>>> fine.
>>>     
>>>       
>> the LFE delay can be played with by changing the starting value of k2.
>> the latency is supposedly N/2 which is 4096 samples, however this may not be 
>> correct.
>> whilst it cant be more than N/2 it may be N/4.
>> Without filtering some parts of male voices gets through into the LFE as 
>> this simple
>> method just uses all the input.
>> somehow the sliding windowed add is adding the rumble in LFE_FILTERED mode, 
>> and is so bad that it cant currently be used.
>> I will do some research into this as I added it to pro_optimizer's code. 
>> There is not much doco on this and the original code was for windows as a 
>> foobar filter.
>>
>> mark
>>
>> _______________________________________________
>> mythtv-dev mailing list
>> mythtv-dev at mythtv.org
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
>>   
>>     
> Hi Mark,
>
> I've just compiled today's SVN with the v35 patch...
>
> On gentoo, I had to emerge fftw-3.1.2 in order to provide a header file 
> required to compile.
>
> Source code version     : 15217M
> SVN Branch              : trunk
> Library API version     : 0.21.20071211-1
> Network Protocol Version: 36
> Options compiled in:
>  linux debug using_oss using_alsa using_backend using_dvb using_frontend 
> using_iptv using_lirc using_v4l using_x11 using_xrandr using_xv 
> using_xvmcw using_bindings_perl using_opengl using_live
>
> Using the ALSA:surround51 device, UK DVB-T, frontend CPU on playback: 55%.
>
> I'm getting constantly broken audio, with a noticable echo, and the 
> following in the logs:
>
> 2007-12-22 16:28:14.691 WriteAudio: buffer underrun
> 2007-12-22 16:28:14.875 WriteAudio: buffer underrun
> 2007-12-22 16:28:15.116 WriteAudio: buffer underrun
> 2007-12-22 16:28:15.330 WriteAudio: buffer underrun
> 2007-12-22 16:28:15.517 WriteAudio: buffer underrun
> 2007-12-22 16:28:15.728 WriteAudio: buffer underrun
> 2007-12-22 16:28:15.910 WriteAudio: buffer underrun
> 2007-12-22 16:28:16.169 WriteAudio: buffer underrun
> 2007-12-22 16:28:16.370 WriteAudio: buffer underrun
> 2007-12-22 16:28:16.686 WriteAudio: buffer underrun
> 2007-12-22 16:28:16.888 WriteAudio: buffer underrun
> 2007-12-22 16:28:17.087 WriteAudio: buffer underrun
> 2007-12-22 16:28:17.293 WriteAudio: buffer underrun
> 2007-12-22 16:28:17.477 WriteAudio: buffer underrun
> 2007-12-22 16:28:17.703 WriteAudio: buffer underrun
> 2007-12-22 16:28:17.904 WriteAudio: buffer underrun
>
> I will try and record a clip of the sound!
>
> Are there any parameters I can tune to try and help?
>
> Paul
>
>
>
>
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
>   
A more complete log with important,general,audio turned on, of starting 
live-tv in the UK with BBC News 24 via DVB-T is below...

PC

2007-12-22 16:37:19.637 AFD: Opened codec 0x959d6c0, id(MPEG2VIDEO) 
type(Video)
2007-12-22 16:37:19.637 AVFD: codec MP3 has 2 channels
2007-12-22 16:37:19.637 AFD: Opened codec 0x8a21960, id(MP3) type(Audio)
2007-12-22 16:37:19.637 AFD: Audio Track #1 is A/V stream #1 and has 2 
channels in the English language(6647399).
2007-12-22 16:37:19.637 AFD: Opened codec 0x95b3550, id(DVB_SUBTITLE) 
type(Subtitle)
2007-12-22 16:37:19.759 AFD: Selected track 1: English MP2 2ch (A/V 
Stream #1)
2007-12-22 16:37:19.759 AFD: Initializing audio parms from audio track #1
2007-12-22 16:37:19.759 AFD: Audio format changed
                        from id(NONE)    -1Hz -1ch   0bps    ; 
id(NONE)    -1Hz -1ch   0bps  
                        to   id( MP3) 48000Hz  2ch  16bps    ; id( MP3) 
48000Hz  2ch  16bps  
2007-12-22 16:37:19.765 AO: Needs upmix
2007-12-22 16:37:19.765 AO: Killing AudioOutputDSP
2007-12-22 16:37:19.765 Opening audio device 'surround51'. ch 6(2) sr 48000
2007-12-22 16:37:19.765 Opening ALSA audio device 'surround51'.
2007-12-22 16:37:19.849 in SetParameters(format=2, channels=6, 
rate=48000, buffer_time=100000, period_time=25000)
2007-12-22 16:37:19.849 ALSA, Warning: mmap not available, attempting to 
fall back to slow writes.
2007-12-22 16:37:19.849 get_buffer_size returned 4800
2007-12-22 16:37:19.850 set_period_time_near returned 25000
2007-12-22 16:37:19.850 get_period_size returned 1200
2007-12-22 16:37:19.855 Opening mixer default
2007-12-22 16:37:19.866 Setting Master volume to 80
2007-12-22 16:37:19.866 Volume range is 0 to 31, mult=3.22581
2007-12-22 16:37:19.866 channel 0 vol set to 25
2007-12-22 16:37:19.866 Setting Master volume to 80
2007-12-22 16:37:19.866 Volume range is 0 to 31, mult=3.22581
2007-12-22 16:37:19.867 channel 1 vol set to 25
2007-12-22 16:37:19.870 Setting PCM volume to 100
2007-12-22 16:37:19.870 Volume range is 0 to 31, mult=3.22581
2007-12-22 16:37:19.870 channel 0 vol set to 31
2007-12-22 16:37:19.870 Setting PCM volume to 100
2007-12-22 16:37:19.870 Volume range is 0 to 31, mult=3.22581
2007-12-22 16:37:19.870 channel 1 vol set to 31
2007-12-22 16:37:19.870 Volume range is 0 to 255, mult=0.392157
2007-12-22 16:37:19.870 AO: Audio fragment size: 19200
2007-12-22 16:37:19.876 AO: create upmixer
2007-12-22 16:37:20.560 NVP: Prebuffer wait timed out 10 times.
2007-12-22 16:37:21.054 AO: create upmixer done
2007-12-22 16:37:21.054 AO: Audio Stretch Factor: 1
2007-12-22 16:37:21.054 Audio Codec Used: not set
2007-12-22 16:37:21.054 AO: Ending reconfigure
2007-12-22 16:37:21.054 NVP: Enabling Audio
2007-12-22 16:37:21.054 AO: Needs upmix
2007-12-22 16:37:21.054 AO: no change exiting
2007-12-22 16:37:21.055 AO: kickoffOutputAudioLoop: pid = 17678
2007-12-22 16:37:21.055 AO: OutputAudioLoop: Play Event
2007-12-22 16:37:21.065 AO: Pause 1
2007-12-22 16:37:21.065 AO: OutputAudioLoop: audio paused
2007-12-22 16:37:21.816 AO: Pause 0
2007-12-22 16:37:21.817 AO: OutputAudioLoop: Play Event
2007-12-22 16:37:21.946 WriteAudio: buffer underrun
2007-12-22 16:37:22.083 WriteAudio: buffer underrun
2007-12-22 16:37:22.231 WriteAudio: buffer underrun
2007-12-22 16:37:22.370 WriteAudio: buffer underrun
2007-12-22 16:37:22.515 WriteAudio: buffer underrun
2007-12-22 16:37:22.666 WriteAudio: buffer underrun
2007-12-22 16:37:22.821 WriteAudio: buffer underrun
2007-12-22 16:37:22.959 WriteAudio: buffer underrun
2007-12-22 16:37:23.088 WriteAudio: buffer underrun
2007-12-22 16:37:23.217 WriteAudio: buffer underrun
2007-12-22 16:37:23.442 WriteAudio: buffer underrun
2007-12-22 16:37:23.696 WriteAudio: buffer underrun