[mythtv-users] hdpvr audio question

glen glenb at glenb.us
Sun Nov 17 23:49:54 UTC 2013


On 11/17/2013 03:41 PM, Devin Heitmueller wrote:
> On Sun, Nov 17, 2013 at 6:36 PM, glen <glenb at glenb.us> wrote:
>> I use a hdpvr with a motorola dcx6200 box. it works well. i have only analog
>> audio through rca cables from box to hdpvr. i would like to change it from
>> ac3 to aac encoding to make transcoding easier. i set the recording profiles
>> to aac, but it always records 2 channel ac3.
>>
>> when i test the device (after changing audio encoding to 3) with cat
>> /dev/video0 > test.ts it will record aac no problem. looking in the log, i
>> get this:
>>
>>   E SignalMonitor recorders/analogsignalmonitor.cpp:95 (VerifyHDPVRaudio)
>> AnalogSigMon[6](/dev/video0): Changed audio encoding from 3 to 4
>>
>> which is changing the mode no matter what i set. i am on .27fixes, is there
>> any way to avoid this and get the aac setting to work ?
> Do you have the RCA audio input selected?  The HDPVR hardware can only
> record AC3 over optical since it doesn't actually have an AC3 encoder
> (it just stores the AC3 bitstream), and AC3 cannot be delivered over
> RCA.
>
> In short, it sounds like MythTV is configured to record on the optical
> input (and the settop box is putting out bitstream AC3 over optical).
>
> Devin
>
yes rca audio input is selected i am getting sound. the codec shows as 
ac3 2 channel; i want aac 2 channel. the setting is audio_encoding, it 
defaults to 3 (aac). outside of myth it does record as aac 2 channel. 
when in myth it changes the setting from 3 to 4 (ac3), regardless of the 
setting in recording profiles. the log indicates it is a process 
verifyhdpvraudio that is making the change. i would it left at the 
default which is 3. i am not using optical and myth is not setup for 
optical; there are 3 settings optical, rca front, rca back. mine are 
plugged to rca at the back and myth is set that way.


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