[mythtv-users] High end, state of the art Myth Frontend

[Michael T. Dean]

On 09/18/2013 04:36 PM, Joseph Fry wrote:
>>> No, 1080i60 has exactly as many pixels as 1080p30.
>> I'm not talking about 1080p30.
>>
>>>   the number of pixels
>>> required for 1080p60 wouldn't fit into the 19.39Mbps bandwidth available
>>> with sufficient picture quality
>> Citation needed.
>>
>> This statement is extremely hard for me to accept.
> Because it's not entirely true.

And is not what I said.  What I actually said--before some over-zealous 
clipping--was:
>>> the number of pixels required for 1080p60 wouldn't fit into the 
>>> 19.39Mbps bandwidth available with sufficient picture quality (using 
>>> the MPEG-2 encoders available at the time the standard was made), 
>>> 1080p60 wasn't an option. 

Where the missing, "using the MPEG-2 encoders available at the time," 
part is a very important part, and seems to be pretty much what Joseph 
is saying, below, too.

> Within the limits that the ATSC allows, it's true.  Theoretically,
> compressing a 1080p/60 video would use twice the bandwidth of
> compressing a 1080i/60 video at the same level of quality.  In reality
> that's not true because a) file size is not directly related to
> resolution, b) the higher amount of detail would allow a greater
> percentage of compression without a perceptible difference quality.
>
> But the fact of the matter is, compressing a 1080p/60 signal will
> result in a larger bandwidth file than compressing 1080i/60 to the
> same perceptible quality level.  Your starting with double the data,
> and if you try to compress it into the same bandwidth using the same
> compression settings, you will introduce more artifacts.
>
> That said, by changing the compression used, and subsequently the
> capabilities of the decoder, you could definately compress a 1080p
> signal into the same bandwidth without perceptible loss of quality.
> But that would mean that the receiver would need to support
> compression outside what the ATSC allows.  Which is why ATSC 2 is
> being introduced.  It adds h264 compression and 1080p/60 to the
> standard (among other things).

Mike