[mythtv-users] Capturing 5.1 audio

[Michael T. Dean]

On 11/12/05 19:05, Nathan Allen Stratton wrote:

>On Sat, 12 Nov 2005, Michael T. Dean wrote:
>
>>ATSC requires
>>the use of AC-3 for audio content (although they call it A/52), so no
>>extra work is required to get it.
>>
>Ok, so with my hdtv card I am stuck using ac-3 for audio vs mp3, how bad
>is this going to kill me on disk space?
>
Multi-channel AC-3 generally takes around 448kbps, which translates to 
about 3.25 MiB/min or 192.25 MiB/hr.  If you have a 192kbps 2-channel 
MP3 stream, it takes about 1.4MiB/min or 82.4MiB/hr.  So, even if you 
transcode the audio to a 2-channel MP3, you're only saving about 110MiB/hr.

However, in general, you can expect the already-encoded digital content 
(audio and video combined) to run you about 4-10 GiB/hr (probably 
averaging about 7 GiB/hr).  Therefore, the audio portion is negligible 
compared to the video.  Even on a 4GiB/hr video stream, the 110MiB we 
saved above is only 1min 30sec of video.

Mike