[mythtv-users] Australian Program Streams

Hamish Moffatt hamish at cloud.net.au
Sun Jun 12 14:33:59 UTC 2005

On Sat, Jun 04, 2005 at 05:36:54PM +1000, Paul Andreassen wrote:
> Why would "ABC HD", "SC HD" and "7 HD" have lower bit rates then their 
> standard definition counterparts?
> I can't see the advantage of high definition if it is twice the frame rate but 
> at a lower bitrate like "7 HD".  "WIN HD" is four times the size but only 60% 
> large bit rate.
> Is high definition is a waste of time or what am I missing?
> ABC    VIDEO:MPEG2 720x576 (aspect 3) 25.000fps 15000.0kbps (1875.0kbyte/s)
> ABC HD Videostream:ASPECT: 16:9 Size=720x576   FRate:50fps BRate: 8.50Mbit/s
> ABC2   VIDEO:MPEG2 720x576 (aspect 3) 25.000fps 15000.0kbps (1875.0kbyte/s)

I don't think the bitrate numbers for ABC and ABC2 are correct there.
It's claiming 15Mbit/sec each for those two, plus another 8.5Mbit/sec
for ABC HD. However total DVB-T bandwidth in our 7MHz channels is only
19-23Mbit/sec (depending on the FEC parameters).

I think the HD number might be correct but the others wrong.
Try using dvbsnoop to get bandwidth data for each.

Also the SDTV streams often have both MPEG and AC3 audio streams, while
the HD streams have AC3 only.

Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>

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