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I have an SA4250HD, and I don't see any way to force the box to output
AC3 instead of AAC for stereo. However, you can set the HD-PVR to
encode AC3 (even for stereo channels) as follows:<br>
<br>
v4l2-ctl --device=/dev/video0 --set-ctrl=audio_encoding=4<br>
<br>
It appears to get reset on system boot (or back-end restart?), so you
may want to add it to rc.local. Experiment first, however. It would
be nice if we could set this in the MythTV recording profile for the
HD-PVR.<br>
<br>
I was trying to force the audio to AC3, as I noticed that the PS3
(DLNA front-end) doesn't seem to like stereo AAC stereo streamed from
MythTV - I get no sound at all. However, after setting the audio
encoding as above, I recorded three programs in a row that would
normally have been in stereo AAC, and the PS3 identified the audio as
AC3 and played it fine - making it a pretty nice front-end for HD-PVR
recordings.<br>
<br>
A caution though.... on my system (trunk 20737) the AC3 audio appears
to break the preview generating process and results in a debilitating
stream of messages on the back-end:<br>
<br>
2009-06-23 05:59:36.862 [libfaad @ 0x7ff6cc838460]faac: frame decoding
failed: Gain control not yet implemented<br>
2009-06-23 05:59:36.862 [libfaad @ 0x7ff6cc838460]faac: frame decoding
failed: Bitstream value not allowed by specification<br>
<br>
Anyone have any thoughts on how to fix this one?<br>
<br>
<br>
The other thing I haven't got to grips with is how to cut commercials
out of the H264 recording.... I don't want to have to manually skip
over commercials using the PS3 (ffd/rwd are a bit touchy anyway when
streaming) so I'd really like to find a solution to cutting them out
automatically. I've searched and it seems to simply be not supported
for H264.<br>
<br>
I'm on Rogers cable in Canada, and all channels are encrypted, so all
of my recordings are through the HD-PVR and in H264.<br>
<br>
Phil<br>
<br>
<blockquote type="cite"><font size="2" color="black"
face="Verdana,Arial,Helvetica"><font size="2" color="black"
face="Verdana,Arial,Helvetica">Yes, it is doing that for the 5.1 HD
channels. The problem is with the <br>
analog channels that only have stereo sound to begin with. I don't
think the <br>
SA3250HD can be set to output bitstream rather than PCM for analog
stereo <br>
sources. <br>
<br>
On Mon, Jun 15, 2009 at 6:11 PM, John P Poet
<jppoet[at]gmail.com> wrote: <br>
<br>
<font color="#660066">> On Mon, Jun 15, 2009 at 3:56 PM,
Christopher <br>
> Meredith<chmeredith[at]gmail.com> wrote: <br>
</font><font color="#007777">> > I don't seem to see a way to
do that on my SA3250HD. My problem was that <br>
</font><font color="#660066">> my <br>
</font><font color="#007777">> > commercial cutting script
doesn't like AAC audio. Fortunately, after lots <br>
</font><font color="#660066">> of <br>
</font><font color="#007777">> > trial and error, I got it to
work by converting the audio track to AC3 <br>
> > first. Ugly, yes. But it works. <br>
</font><font color="#660066">> <br>
> I am not at home, so I can't check at the moment, but the choice
of <br>
> AAC/AC3 for PCM input is probably under the recording profiles. <br>
> <br>
> It would be better to get the STB to pass-through Dolby Digital, <br>
> though. Having it downmix the AC3 to PCM, and then having the
HD-PVR <br>
> turn it back into AC3 is likely to incur noticeable loss. <br>
> <br>
> There has to be a way to set the SA3250HD to output dolby digital.
A <br>
> little googling, and I see people talking about a "Digital Out"
option <br>
> somewhere in it's settings. <br>
> <br>
> <br>
> John </font></font></font></blockquote>
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