[mythtv-users] Capturing 5.1 audio

Bob spam at homeurl.co.uk
Tue Nov 15 03:09:30 EST 2005

Steve Adeff wrote:
> On Saturday 12 November 2005 23:41, Michael T. Dean wrote:
>>On 11/12/05 19:55, Nathan Allen Stratton wrote:
>>>On Sat, 12 Nov 2005, Michael T. Dean wrote:
>>>>Nope.  ATSC (US high-definition TV) is broadcast already encoded using
>>>>the MPEG-2 system.  The audio is encoded in an AC-3 stream within the
>>>>transport stream.  So, it's just there.
>>>Hmm so since I setup the mp3 audio encoding on the video profiles I would
>>>trash the AC-3 stream off my hdtv card. Yet, if I dont compress audio my
>>>hdtv card audio will be AC-3, but I will suck up huge space with the 44K
>>>audio off my 2 plextor boxes.
>>AIUI, those parameters (and bitrate, etc.) of the profile are not used
>>for HDTV capture cards since the stream is just dumped to disk.  So, you
>>can set the audio encoding to whatever you'd like.
> how much CPU would it take to capture and encode video from a non-PVR capture 
> card so that it can be muxed with the audio from a soundcard? I ask because I 
> happen to have an older WinTV card laying around. I'd even be willing to 
> accept a lossless capture format to allow for easy live TV with AC3, with the 
> ability to convert to XviD later if I decided to keep the recording.
> Steve

About a spoon full.

But seriously, lossless compression tends to be more cpu intensive than 
lossy, particularly if your aiming for respectable compression ratios, 
if your not even SD content is going to take up a *lot* of space very fast.

As for how much CPU to capture from a frame grabber look at

tveeprom: Hauppauge: model = 34132, rev = J158,
tveeprom: tuner = Philips FM1236 MK3 (idx = 58, type = 4)
tveeprom: audio_processor = MSP3416 (type = 14)
(new type Model 401)
model name      : mobile AMD Athlon(tm) XP Processor
cpu MHz         : 2277.214
cache size      : 512 KB
(Plenty o' grunt on an ECS k7s5a MB)
Knoppmyth R5A16 (unmodified)
<a href="http://mysettopbox.tv/CHANGELOG.txt">Knoppmyth Changelog</a>
MythTV 0.18.1

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