[pvrusb2] audio pops and cracks in the recordings

[Mike Isely]

On Sun, 21 Jan 2007, devsk wrote:

> Hi,
> 
> I am using 20061119 snapshot with 2.6.19.2 kernel. I get pops and cracks in the sound. My settings are as follows:
> 
> $ cat ctl_audio_layer/cur_val
> Layer II
> 
> $ cat /sys/class/pvrusb2/sn-*/ctl_volume/cur_val
> 53710
> 
> $ cat /sys/class/pvrusb2/sn-*/ctl_audio_bitrate/cur_val
> 224 kbps
> 
> $ cat ctl_audio_mode/cur_val
> Stereo
> 
> $ cat ctl_audio_emphasis/cur_val
> No Emphasis
> 
> $ cat ctl_audio_crc/cur_val
> No CRC
> 
> I have these put into the /etc/init.d/local.start:
>  
> echo "10485760" > /sys/class/pvrusb2/sn-*/ctl_video_bitrate_peak/cur_val
> echo "8388608" > /sys/class/pvrusb2/sn-*/ctl_video_bitrate/cur_val
> echo "Constant Bitrate" > /sys/class/pvrusb2/sn-*/ctl_video_bitrate_mode/cur_val
> echo "224 kbps" > /sys/class/pvrusb2/sn-*/ctl_audio_bitrate/cur_val
> echo "53738" > /sys/class/pvrusb2/sn-*/ctl_volume/cur_val
> 
> One thing I noticed is that most of the pops/cracks happen in the 
> shows which are telecast in HD 5.1 sound. I am using the regular 
> analog cable to record my shows using mythtv. All (mythtv mixer, 
> recorder, transcoder, pvrusb2) volume levels are set at 82%. I hear 
> the pops in the .mpg file, so its not the transcoder.
> 
> Does anybody have any idea about this problem? It has ruined most of 
> recordings because most of the content that I typical record is 
> telecast in HD 5.1.
> 

Do you know if you are getting a strong enough signal?

If you do NOT do those driver settings / tweaks, do you still see the 
problem?  If not, can you identify which key setting(s) influence this?

  -Mike

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