[mythtv-users] Transcode from HD to SD, what settings?

[Jon Bishop]

On Nov 28, 2008, at 12:12 PM, Allen Edwards wrote:

> I have asked this before and been told basically to experiment.  Maybe
> if I ask it specifically someone knows the answer.
>
> I have an OTA ATSC system.  Every evening I record Jepordy in HD and
> transcode to the lowest quality setting.  This takes a 3.6GB recording
> down to 3.6GB, not much help.  I recode another show off a DT station
> (9.2 in San Francisco) and the same length show takes up only 0.8GB
> and looks just fine on the 37 inch CRT TV with S-Video input that we
> use for watching Jepordy.  We watch the shows about a month after
> broadcast so the time to transcode isn't an issue.  We have a 10 ft
> screen that we use for watching shows in HD, btw.
>
> What I want is to know the transcode settings that will take my 3.6GB
> Jepordy recording down to the same quality I get with the DT station
> and hopefully only use 0.8GB although that may be asking too much.
> But taking a 3.6GB show down to 3.6GB clearly isn't asking enough.


I believe that one of your problems is that you're using one of the  
'canned' settings. As far as I know, these are actually all the same,  
and waiting for the user to customize to their preferences.  
Personally, I have jeopardy set to keep a maximum of 5 recordings,  
expiring the old to record the new. Then, we don't bother with  
transcoding. Same with news (actually, I only keep a single days worth  
of news, but again, no transcoding).

I feel transcoding is useful for files that you intend to watch more  
than once, and want to make save space... but otherwise, it's just a  
waste of CPU cycles to transcode something that's just going to get  
deleted.

For shows that I do intend to keep, I have been transcoding them to  
720p resolution (which I need to change now that I have an HD TV, but  
I digress) as MPEG4 (xvid) with about 1200 for a bitrate. This nets me  
about a gig per hour. The real answer is going to be experimenting and  
finding what is suitable for you. Some people can tolerate a lot more  
picture degredation than others without noticing, or caring (depending  
on the viewer)

~Jon